struct io_context *ioc;
cgroup_taskset_for_each(task, cgrp, tset) {
- task_lock(task);
- ioc = task->io_context;
- if (ioc)
- ioc->cgroup_changed = 1;
- task_unlock(task);
+ /* we don't lose anything even if ioc allocation fails */
+ ioc = get_task_io_context(task, GFP_ATOMIC, NUMA_NO_NODE);
+ if (ioc) {
+ ioc_cgroup_changed(ioc);
+ put_io_context(ioc, NULL);
+ }
}
}
EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete);
+DEFINE_IDA(blk_queue_ida);
+
/*
* For the allocated request tables
*/
void blk_drain_queue(struct request_queue *q, bool drain_all)
{
while (true) {
- int nr_rqs;
+ bool drain = false;
+ int i;
spin_lock_irq(q->queue_lock);
if (!list_empty(&q->queue_head))
__blk_run_queue(q);
- if (drain_all)
- nr_rqs = q->rq.count[0] + q->rq.count[1];
- else
- nr_rqs = q->rq.elvpriv;
+ drain |= q->rq.elvpriv;
+
+ /*
+ * Unfortunately, requests are queued at and tracked from
+ * multiple places and there's no single counter which can
+ * be drained. Check all the queues and counters.
+ */
+ if (drain_all) {
+ drain |= !list_empty(&q->queue_head);
+ for (i = 0; i < 2; i++) {
+ drain |= q->rq.count[i];
+ drain |= q->in_flight[i];
+ drain |= !list_empty(&q->flush_queue[i]);
+ }
+ }
spin_unlock_irq(q->queue_lock);
- if (!nr_rqs)
+ if (!drain)
break;
msleep(10);
}
if (!q)
return NULL;
+ q->id = ida_simple_get(&blk_queue_ida, 0, 0, GFP_KERNEL);
+ if (q->id < 0)
+ goto fail_q;
+
q->backing_dev_info.ra_pages =
(VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
q->backing_dev_info.state = 0;
q->node = node_id;
err = bdi_init(&q->backing_dev_info);
- if (err) {
- kmem_cache_free(blk_requestq_cachep, q);
- return NULL;
- }
+ if (err)
+ goto fail_id;
- if (blk_throtl_init(q)) {
- kmem_cache_free(blk_requestq_cachep, q);
- return NULL;
- }
+ if (blk_throtl_init(q))
+ goto fail_id;
setup_timer(&q->backing_dev_info.laptop_mode_wb_timer,
laptop_mode_timer_fn, (unsigned long) q);
setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q);
INIT_LIST_HEAD(&q->timeout_list);
+ INIT_LIST_HEAD(&q->icq_list);
INIT_LIST_HEAD(&q->flush_queue[0]);
INIT_LIST_HEAD(&q->flush_queue[1]);
INIT_LIST_HEAD(&q->flush_data_in_flight);
q->queue_lock = &q->__queue_lock;
return q;
+
+fail_id:
+ ida_simple_remove(&blk_queue_ida, q->id);
+fail_q:
+ kmem_cache_free(blk_requestq_cachep, q);
+ return NULL;
}
EXPORT_SYMBOL(blk_alloc_queue_node);
}
EXPORT_SYMBOL(blk_init_allocated_queue);
-int blk_get_queue(struct request_queue *q)
+bool blk_get_queue(struct request_queue *q)
{
- if (likely(!test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) {
- kobject_get(&q->kobj);
- return 0;
+ if (likely(!blk_queue_dead(q))) {
+ __blk_get_queue(q);
+ return true;
}
- return 1;
+ return false;
}
EXPORT_SYMBOL(blk_get_queue);
static inline void blk_free_request(struct request_queue *q, struct request *rq)
{
- if (rq->cmd_flags & REQ_ELVPRIV)
+ if (rq->cmd_flags & REQ_ELVPRIV) {
elv_put_request(q, rq);
+ if (rq->elv.icq)
+ put_io_context(rq->elv.icq->ioc, q);
+ }
+
mempool_free(rq, q->rq.rq_pool);
}
static struct request *
-blk_alloc_request(struct request_queue *q, unsigned int flags, gfp_t gfp_mask)
+blk_alloc_request(struct request_queue *q, struct io_cq *icq,
+ unsigned int flags, gfp_t gfp_mask)
{
struct request *rq = mempool_alloc(q->rq.rq_pool, gfp_mask);
rq->cmd_flags = flags | REQ_ALLOCED;
- if ((flags & REQ_ELVPRIV) &&
- unlikely(elv_set_request(q, rq, gfp_mask))) {
- mempool_free(rq, q->rq.rq_pool);
- return NULL;
+ if (flags & REQ_ELVPRIV) {
+ rq->elv.icq = icq;
+ if (unlikely(elv_set_request(q, rq, gfp_mask))) {
+ mempool_free(rq, q->rq.rq_pool);
+ return NULL;
+ }
+ /* @rq->elv.icq holds on to io_context until @rq is freed */
+ if (icq)
+ get_io_context(icq->ioc);
}
return rq;
{
struct request *rq = NULL;
struct request_list *rl = &q->rq;
- struct io_context *ioc = NULL;
+ struct elevator_type *et;
+ struct io_context *ioc;
+ struct io_cq *icq = NULL;
const bool is_sync = rw_is_sync(rw_flags) != 0;
+ bool retried = false;
int may_queue;
+retry:
+ et = q->elevator->type;
+ ioc = current->io_context;
- if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)))
+ if (unlikely(blk_queue_dead(q)))
return NULL;
may_queue = elv_may_queue(q, rw_flags);
if (rl->count[is_sync]+1 >= queue_congestion_on_threshold(q)) {
if (rl->count[is_sync]+1 >= q->nr_requests) {
- ioc = current_io_context(GFP_ATOMIC, q->node);
+ /*
+ * We want ioc to record batching state. If it's
+ * not already there, creating a new one requires
+ * dropping queue_lock, which in turn requires
+ * retesting conditions to avoid queue hang.
+ */
+ if (!ioc && !retried) {
+ spin_unlock_irq(q->queue_lock);
+ create_io_context(current, gfp_mask, q->node);
+ spin_lock_irq(q->queue_lock);
+ retried = true;
+ goto retry;
+ }
+
/*
* The queue will fill after this allocation, so set
* it as full, and mark this process as "batching".
rl->count[is_sync]++;
rl->starved[is_sync] = 0;
+ /*
+ * Decide whether the new request will be managed by elevator. If
+ * so, mark @rw_flags and increment elvpriv. Non-zero elvpriv will
+ * prevent the current elevator from being destroyed until the new
+ * request is freed. This guarantees icq's won't be destroyed and
+ * makes creating new ones safe.
+ *
+ * Also, lookup icq while holding queue_lock. If it doesn't exist,
+ * it will be created after releasing queue_lock.
+ */
if (blk_rq_should_init_elevator(bio) &&
!test_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags)) {
rw_flags |= REQ_ELVPRIV;
rl->elvpriv++;
+ if (et->icq_cache && ioc)
+ icq = ioc_lookup_icq(ioc, q);
}
if (blk_queue_io_stat(q))
rw_flags |= REQ_IO_STAT;
spin_unlock_irq(q->queue_lock);
- rq = blk_alloc_request(q, rw_flags, gfp_mask);
+ /* create icq if missing */
+ if (unlikely(et->icq_cache && !icq))
+ icq = ioc_create_icq(q, gfp_mask);
+
+ /* rqs are guaranteed to have icq on elv_set_request() if requested */
+ if (likely(!et->icq_cache || icq))
+ rq = blk_alloc_request(q, icq, rw_flags, gfp_mask);
+
if (unlikely(!rq)) {
/*
* Allocation failed presumably due to memory. Undo anything
rq = get_request(q, rw_flags, bio, GFP_NOIO);
while (!rq) {
DEFINE_WAIT(wait);
- struct io_context *ioc;
struct request_list *rl = &q->rq;
- if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)))
+ if (unlikely(blk_queue_dead(q)))
return NULL;
prepare_to_wait_exclusive(&rl->wait[is_sync], &wait,
* up to a big batch of them for a small period time.
* See ioc_batching, ioc_set_batching
*/
- ioc = current_io_context(GFP_NOIO, q->node);
- ioc_set_batching(q, ioc);
+ create_io_context(current, GFP_NOIO, q->node);
+ ioc_set_batching(q, current->io_context);
spin_lock_irq(q->queue_lock);
finish_wait(&rl->wait[is_sync], &wait);
__elv_add_request(q, rq, where);
}
-/**
- * blk_insert_request - insert a special request into a request queue
- * @q: request queue where request should be inserted
- * @rq: request to be inserted
- * @at_head: insert request at head or tail of queue
- * @data: private data
- *
- * Description:
- * Many block devices need to execute commands asynchronously, so they don't
- * block the whole kernel from preemption during request execution. This is
- * accomplished normally by inserting aritficial requests tagged as
- * REQ_TYPE_SPECIAL in to the corresponding request queue, and letting them
- * be scheduled for actual execution by the request queue.
- *
- * We have the option of inserting the head or the tail of the queue.
- * Typically we use the tail for new ioctls and so forth. We use the head
- * of the queue for things like a QUEUE_FULL message from a device, or a
- * host that is unable to accept a particular command.
- */
-void blk_insert_request(struct request_queue *q, struct request *rq,
- int at_head, void *data)
-{
- int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;
- unsigned long flags;
-
- /*
- * tell I/O scheduler that this isn't a regular read/write (ie it
- * must not attempt merges on this) and that it acts as a soft
- * barrier
- */
- rq->cmd_type = REQ_TYPE_SPECIAL;
-
- rq->special = data;
-
- spin_lock_irqsave(q->queue_lock, flags);
-
- /*
- * If command is tagged, release the tag
- */
- if (blk_rq_tagged(rq))
- blk_queue_end_tag(q, rq);
-
- add_acct_request(q, rq, where);
- __blk_run_queue(q);
- spin_unlock_irqrestore(q->queue_lock, flags);
-}
-EXPORT_SYMBOL(blk_insert_request);
-
static void part_round_stats_single(int cpu, struct hd_struct *part,
unsigned long now)
{
return -EIO;
spin_lock_irqsave(q->queue_lock, flags);
+ if (unlikely(blk_queue_dead(q))) {
+ spin_unlock_irqrestore(q->queue_lock, flags);
+ return -ENODEV;
+ }
/*
* Submitting request must be dequeued before calling this function
{
trace_block_unplug(q, depth, !from_schedule);
+ /*
+ * Don't mess with dead queue.
+ */
+ if (unlikely(blk_queue_dead(q))) {
+ spin_unlock(q->queue_lock);
+ return;
+ }
+
/*
* If we are punting this to kblockd, then we can safely drop
* the queue_lock before waking kblockd (which needs to take
depth = 0;
spin_lock(q->queue_lock);
}
+
+ /*
+ * Short-circuit if @q is dead
+ */
+ if (unlikely(blk_queue_dead(q))) {
+ __blk_end_request_all(rq, -ENODEV);
+ continue;
+ }
+
/*
* rq is already accounted, so use raw insert
*/
{
int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;
- if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) {
+ WARN_ON(irqs_disabled());
+ spin_lock_irq(q->queue_lock);
+
+ if (unlikely(blk_queue_dead(q))) {
+ spin_unlock_irq(q->queue_lock);
rq->errors = -ENXIO;
if (rq->end_io)
rq->end_io(rq, rq->errors);
rq->rq_disk = bd_disk;
rq->end_io = done;
- WARN_ON(irqs_disabled());
- spin_lock_irq(q->queue_lock);
__elv_add_request(q, rq, where);
__blk_run_queue(q);
/* the queue is stopped so it won't be run */
*/
static struct kmem_cache *iocontext_cachep;
-static void cfq_dtor(struct io_context *ioc)
+/**
+ * get_io_context - increment reference count to io_context
+ * @ioc: io_context to get
+ *
+ * Increment reference count to @ioc.
+ */
+void get_io_context(struct io_context *ioc)
+{
+ BUG_ON(atomic_long_read(&ioc->refcount) <= 0);
+ atomic_long_inc(&ioc->refcount);
+}
+EXPORT_SYMBOL(get_io_context);
+
+/*
+ * Releasing ioc may nest into another put_io_context() leading to nested
+ * fast path release. As the ioc's can't be the same, this is okay but
+ * makes lockdep whine. Keep track of nesting and use it as subclass.
+ */
+#ifdef CONFIG_LOCKDEP
+#define ioc_release_depth(q) ((q) ? (q)->ioc_release_depth : 0)
+#define ioc_release_depth_inc(q) (q)->ioc_release_depth++
+#define ioc_release_depth_dec(q) (q)->ioc_release_depth--
+#else
+#define ioc_release_depth(q) 0
+#define ioc_release_depth_inc(q) do { } while (0)
+#define ioc_release_depth_dec(q) do { } while (0)
+#endif
+
+static void icq_free_icq_rcu(struct rcu_head *head)
+{
+ struct io_cq *icq = container_of(head, struct io_cq, __rcu_head);
+
+ kmem_cache_free(icq->__rcu_icq_cache, icq);
+}
+
+/*
+ * Exit and free an icq. Called with both ioc and q locked.
+ */
+static void ioc_exit_icq(struct io_cq *icq)
{
- if (!hlist_empty(&ioc->cic_list)) {
- struct cfq_io_context *cic;
+ struct io_context *ioc = icq->ioc;
+ struct request_queue *q = icq->q;
+ struct elevator_type *et = q->elevator->type;
+
+ lockdep_assert_held(&ioc->lock);
+ lockdep_assert_held(q->queue_lock);
+
+ radix_tree_delete(&ioc->icq_tree, icq->q->id);
+ hlist_del_init(&icq->ioc_node);
+ list_del_init(&icq->q_node);
+
+ /*
+ * Both setting lookup hint to and clearing it from @icq are done
+ * under queue_lock. If it's not pointing to @icq now, it never
+ * will. Hint assignment itself can race safely.
+ */
+ if (rcu_dereference_raw(ioc->icq_hint) == icq)
+ rcu_assign_pointer(ioc->icq_hint, NULL);
- cic = hlist_entry(ioc->cic_list.first, struct cfq_io_context,
- cic_list);
- cic->dtor(ioc);
+ if (et->ops.elevator_exit_icq_fn) {
+ ioc_release_depth_inc(q);
+ et->ops.elevator_exit_icq_fn(icq);
+ ioc_release_depth_dec(q);
}
+
+ /*
+ * @icq->q might have gone away by the time RCU callback runs
+ * making it impossible to determine icq_cache. Record it in @icq.
+ */
+ icq->__rcu_icq_cache = et->icq_cache;
+ call_rcu(&icq->__rcu_head, icq_free_icq_rcu);
}
/*
- * IO Context helper functions. put_io_context() returns 1 if there are no
- * more users of this io context, 0 otherwise.
+ * Slow path for ioc release in put_io_context(). Performs double-lock
+ * dancing to unlink all icq's and then frees ioc.
*/
-int put_io_context(struct io_context *ioc)
+static void ioc_release_fn(struct work_struct *work)
{
- if (ioc == NULL)
- return 1;
+ struct io_context *ioc = container_of(work, struct io_context,
+ release_work);
+ struct request_queue *last_q = NULL;
- BUG_ON(atomic_long_read(&ioc->refcount) == 0);
+ spin_lock_irq(&ioc->lock);
- if (atomic_long_dec_and_test(&ioc->refcount)) {
- rcu_read_lock();
- cfq_dtor(ioc);
- rcu_read_unlock();
+ while (!hlist_empty(&ioc->icq_list)) {
+ struct io_cq *icq = hlist_entry(ioc->icq_list.first,
+ struct io_cq, ioc_node);
+ struct request_queue *this_q = icq->q;
- kmem_cache_free(iocontext_cachep, ioc);
- return 1;
+ if (this_q != last_q) {
+ /*
+ * Need to switch to @this_q. Once we release
+ * @ioc->lock, it can go away along with @cic.
+ * Hold on to it.
+ */
+ __blk_get_queue(this_q);
+
+ /*
+ * blk_put_queue() might sleep thanks to kobject
+ * idiocy. Always release both locks, put and
+ * restart.
+ */
+ if (last_q) {
+ spin_unlock(last_q->queue_lock);
+ spin_unlock_irq(&ioc->lock);
+ blk_put_queue(last_q);
+ } else {
+ spin_unlock_irq(&ioc->lock);
+ }
+
+ last_q = this_q;
+ spin_lock_irq(this_q->queue_lock);
+ spin_lock(&ioc->lock);
+ continue;
+ }
+ ioc_exit_icq(icq);
}
- return 0;
+
+ if (last_q) {
+ spin_unlock(last_q->queue_lock);
+ spin_unlock_irq(&ioc->lock);
+ blk_put_queue(last_q);
+ } else {
+ spin_unlock_irq(&ioc->lock);
+ }
+
+ kmem_cache_free(iocontext_cachep, ioc);
}
-EXPORT_SYMBOL(put_io_context);
-static void cfq_exit(struct io_context *ioc)
+/**
+ * put_io_context - put a reference of io_context
+ * @ioc: io_context to put
+ * @locked_q: request_queue the caller is holding queue_lock of (hint)
+ *
+ * Decrement reference count of @ioc and release it if the count reaches
+ * zero. If the caller is holding queue_lock of a queue, it can indicate
+ * that with @locked_q. This is an optimization hint and the caller is
+ * allowed to pass in %NULL even when it's holding a queue_lock.
+ */
+void put_io_context(struct io_context *ioc, struct request_queue *locked_q)
{
- rcu_read_lock();
+ struct request_queue *last_q = locked_q;
+ unsigned long flags;
+
+ if (ioc == NULL)
+ return;
+
+ BUG_ON(atomic_long_read(&ioc->refcount) <= 0);
+ if (locked_q)
+ lockdep_assert_held(locked_q->queue_lock);
- if (!hlist_empty(&ioc->cic_list)) {
- struct cfq_io_context *cic;
+ if (!atomic_long_dec_and_test(&ioc->refcount))
+ return;
+
+ /*
+ * Destroy @ioc. This is a bit messy because icq's are chained
+ * from both ioc and queue, and ioc->lock nests inside queue_lock.
+ * The inner ioc->lock should be held to walk our icq_list and then
+ * for each icq the outer matching queue_lock should be grabbed.
+ * ie. We need to do reverse-order double lock dancing.
+ *
+ * Another twist is that we are often called with one of the
+ * matching queue_locks held as indicated by @locked_q, which
+ * prevents performing double-lock dance for other queues.
+ *
+ * So, we do it in two stages. The fast path uses the queue_lock
+ * the caller is holding and, if other queues need to be accessed,
+ * uses trylock to avoid introducing locking dependency. This can
+ * handle most cases, especially if @ioc was performing IO on only
+ * single device.
+ *
+ * If trylock doesn't cut it, we defer to @ioc->release_work which
+ * can do all the double-locking dancing.
+ */
+ spin_lock_irqsave_nested(&ioc->lock, flags,
+ ioc_release_depth(locked_q));
- cic = hlist_entry(ioc->cic_list.first, struct cfq_io_context,
- cic_list);
- cic->exit(ioc);
+ while (!hlist_empty(&ioc->icq_list)) {
+ struct io_cq *icq = hlist_entry(ioc->icq_list.first,
+ struct io_cq, ioc_node);
+ struct request_queue *this_q = icq->q;
+
+ if (this_q != last_q) {
+ if (last_q && last_q != locked_q)
+ spin_unlock(last_q->queue_lock);
+ last_q = NULL;
+
+ if (!spin_trylock(this_q->queue_lock))
+ break;
+ last_q = this_q;
+ continue;
+ }
+ ioc_exit_icq(icq);
}
- rcu_read_unlock();
+
+ if (last_q && last_q != locked_q)
+ spin_unlock(last_q->queue_lock);
+
+ spin_unlock_irqrestore(&ioc->lock, flags);
+
+ /* if no icq is left, we're done; otherwise, kick release_work */
+ if (hlist_empty(&ioc->icq_list))
+ kmem_cache_free(iocontext_cachep, ioc);
+ else
+ schedule_work(&ioc->release_work);
}
+EXPORT_SYMBOL(put_io_context);
/* Called by the exiting task */
void exit_io_context(struct task_struct *task)
task->io_context = NULL;
task_unlock(task);
- if (atomic_dec_and_test(&ioc->nr_tasks))
- cfq_exit(ioc);
+ atomic_dec(&ioc->nr_tasks);
+ put_io_context(ioc, NULL);
+}
+
+/**
+ * ioc_clear_queue - break any ioc association with the specified queue
+ * @q: request_queue being cleared
+ *
+ * Walk @q->icq_list and exit all io_cq's. Must be called with @q locked.
+ */
+void ioc_clear_queue(struct request_queue *q)
+{
+ lockdep_assert_held(q->queue_lock);
+
+ while (!list_empty(&q->icq_list)) {
+ struct io_cq *icq = list_entry(q->icq_list.next,
+ struct io_cq, q_node);
+ struct io_context *ioc = icq->ioc;
- put_io_context(ioc);
+ spin_lock(&ioc->lock);
+ ioc_exit_icq(icq);
+ spin_unlock(&ioc->lock);
+ }
}
-struct io_context *alloc_io_context(gfp_t gfp_flags, int node)
+void create_io_context_slowpath(struct task_struct *task, gfp_t gfp_flags,
+ int node)
{
struct io_context *ioc;
- ioc = kmem_cache_alloc_node(iocontext_cachep, gfp_flags, node);
- if (ioc) {
- atomic_long_set(&ioc->refcount, 1);
- atomic_set(&ioc->nr_tasks, 1);
- spin_lock_init(&ioc->lock);
- ioc->ioprio_changed = 0;
- ioc->ioprio = 0;
- ioc->last_waited = 0; /* doesn't matter... */
- ioc->nr_batch_requests = 0; /* because this is 0 */
- INIT_RADIX_TREE(&ioc->radix_root, GFP_ATOMIC | __GFP_HIGH);
- INIT_HLIST_HEAD(&ioc->cic_list);
- ioc->ioc_data = NULL;
-#if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)
- ioc->cgroup_changed = 0;
-#endif
- }
+ ioc = kmem_cache_alloc_node(iocontext_cachep, gfp_flags | __GFP_ZERO,
+ node);
+ if (unlikely(!ioc))
+ return;
- return ioc;
+ /* initialize */
+ atomic_long_set(&ioc->refcount, 1);
+ atomic_set(&ioc->nr_tasks, 1);
+ spin_lock_init(&ioc->lock);
+ INIT_RADIX_TREE(&ioc->icq_tree, GFP_ATOMIC | __GFP_HIGH);
+ INIT_HLIST_HEAD(&ioc->icq_list);
+ INIT_WORK(&ioc->release_work, ioc_release_fn);
+
+ /*
+ * Try to install. ioc shouldn't be installed if someone else
+ * already did or @task, which isn't %current, is exiting. Note
+ * that we need to allow ioc creation on exiting %current as exit
+ * path may issue IOs from e.g. exit_files(). The exit path is
+ * responsible for not issuing IO after exit_io_context().
+ */
+ task_lock(task);
+ if (!task->io_context &&
+ (task == current || !(task->flags & PF_EXITING)))
+ task->io_context = ioc;
+ else
+ kmem_cache_free(iocontext_cachep, ioc);
+ task_unlock(task);
}
-/*
- * If the current task has no IO context then create one and initialise it.
- * Otherwise, return its existing IO context.
+/**
+ * get_task_io_context - get io_context of a task
+ * @task: task of interest
+ * @gfp_flags: allocation flags, used if allocation is necessary
+ * @node: allocation node, used if allocation is necessary
*
- * This returned IO context doesn't have a specifically elevated refcount,
- * but since the current task itself holds a reference, the context can be
- * used in general code, so long as it stays within `current` context.
+ * Return io_context of @task. If it doesn't exist, it is created with
+ * @gfp_flags and @node. The returned io_context has its reference count
+ * incremented.
+ *
+ * This function always goes through task_lock() and it's better to use
+ * %current->io_context + get_io_context() for %current.
*/
-struct io_context *current_io_context(gfp_t gfp_flags, int node)
+struct io_context *get_task_io_context(struct task_struct *task,
+ gfp_t gfp_flags, int node)
{
- struct task_struct *tsk = current;
- struct io_context *ret;
-
- ret = tsk->io_context;
- if (likely(ret))
- return ret;
-
- ret = alloc_io_context(gfp_flags, node);
- if (ret) {
- /* make sure set_task_ioprio() sees the settings above */
- smp_wmb();
- tsk->io_context = ret;
- }
+ struct io_context *ioc;
- return ret;
+ might_sleep_if(gfp_flags & __GFP_WAIT);
+
+ do {
+ task_lock(task);
+ ioc = task->io_context;
+ if (likely(ioc)) {
+ get_io_context(ioc);
+ task_unlock(task);
+ return ioc;
+ }
+ task_unlock(task);
+ } while (create_io_context(task, gfp_flags, node));
+
+ return NULL;
}
+EXPORT_SYMBOL(get_task_io_context);
-/*
- * If the current task has no IO context then create one and initialise it.
- * If it does have a context, take a ref on it.
+/**
+ * ioc_lookup_icq - lookup io_cq from ioc
+ * @ioc: the associated io_context
+ * @q: the associated request_queue
*
- * This is always called in the context of the task which submitted the I/O.
+ * Look up io_cq associated with @ioc - @q pair from @ioc. Must be called
+ * with @q->queue_lock held.
*/
-struct io_context *get_io_context(gfp_t gfp_flags, int node)
+struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q)
{
- struct io_context *ioc = NULL;
+ struct io_cq *icq;
+
+ lockdep_assert_held(q->queue_lock);
/*
- * Check for unlikely race with exiting task. ioc ref count is
- * zero when ioc is being detached.
+ * icq's are indexed from @ioc using radix tree and hint pointer,
+ * both of which are protected with RCU. All removals are done
+ * holding both q and ioc locks, and we're holding q lock - if we
+ * find a icq which points to us, it's guaranteed to be valid.
*/
- do {
- ioc = current_io_context(gfp_flags, node);
- if (unlikely(!ioc))
- break;
- } while (!atomic_long_inc_not_zero(&ioc->refcount));
+ rcu_read_lock();
+ icq = rcu_dereference(ioc->icq_hint);
+ if (icq && icq->q == q)
+ goto out;
- return ioc;
+ icq = radix_tree_lookup(&ioc->icq_tree, q->id);
+ if (icq && icq->q == q)
+ rcu_assign_pointer(ioc->icq_hint, icq); /* allowed to race */
+ else
+ icq = NULL;
+out:
+ rcu_read_unlock();
+ return icq;
}
-EXPORT_SYMBOL(get_io_context);
+EXPORT_SYMBOL(ioc_lookup_icq);
+
+/**
+ * ioc_create_icq - create and link io_cq
+ * @q: request_queue of interest
+ * @gfp_mask: allocation mask
+ *
+ * Make sure io_cq linking %current->io_context and @q exists. If either
+ * io_context and/or icq don't exist, they will be created using @gfp_mask.
+ *
+ * The caller is responsible for ensuring @ioc won't go away and @q is
+ * alive and will stay alive until this function returns.
+ */
+struct io_cq *ioc_create_icq(struct request_queue *q, gfp_t gfp_mask)
+{
+ struct elevator_type *et = q->elevator->type;
+ struct io_context *ioc;
+ struct io_cq *icq;
+
+ /* allocate stuff */
+ ioc = create_io_context(current, gfp_mask, q->node);
+ if (!ioc)
+ return NULL;
+
+ icq = kmem_cache_alloc_node(et->icq_cache, gfp_mask | __GFP_ZERO,
+ q->node);
+ if (!icq)
+ return NULL;
+
+ if (radix_tree_preload(gfp_mask) < 0) {
+ kmem_cache_free(et->icq_cache, icq);
+ return NULL;
+ }
+
+ icq->ioc = ioc;
+ icq->q = q;
+ INIT_LIST_HEAD(&icq->q_node);
+ INIT_HLIST_NODE(&icq->ioc_node);
+
+ /* lock both q and ioc and try to link @icq */
+ spin_lock_irq(q->queue_lock);
+ spin_lock(&ioc->lock);
+
+ if (likely(!radix_tree_insert(&ioc->icq_tree, q->id, icq))) {
+ hlist_add_head(&icq->ioc_node, &ioc->icq_list);
+ list_add(&icq->q_node, &q->icq_list);
+ if (et->ops.elevator_init_icq_fn)
+ et->ops.elevator_init_icq_fn(icq);
+ } else {
+ kmem_cache_free(et->icq_cache, icq);
+ icq = ioc_lookup_icq(ioc, q);
+ if (!icq)
+ printk(KERN_ERR "cfq: icq link failed!\n");
+ }
+
+ spin_unlock(&ioc->lock);
+ spin_unlock_irq(q->queue_lock);
+ radix_tree_preload_end();
+ return icq;
+}
+
+void ioc_set_changed(struct io_context *ioc, int which)
+{
+ struct io_cq *icq;
+ struct hlist_node *n;
+
+ hlist_for_each_entry(icq, n, &ioc->icq_list, ioc_node)
+ set_bit(which, &icq->changed);
+}
+
+/**
+ * ioc_ioprio_changed - notify ioprio change
+ * @ioc: io_context of interest
+ * @ioprio: new ioprio
+ *
+ * @ioc's ioprio has changed to @ioprio. Set %ICQ_IOPRIO_CHANGED for all
+ * icq's. iosched is responsible for checking the bit and applying it on
+ * request issue path.
+ */
+void ioc_ioprio_changed(struct io_context *ioc, int ioprio)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&ioc->lock, flags);
+ ioc->ioprio = ioprio;
+ ioc_set_changed(ioc, ICQ_IOPRIO_CHANGED);
+ spin_unlock_irqrestore(&ioc->lock, flags);
+}
+
+/**
+ * ioc_cgroup_changed - notify cgroup change
+ * @ioc: io_context of interest
+ *
+ * @ioc's cgroup has changed. Set %ICQ_CGROUP_CHANGED for all icq's.
+ * iosched is responsible for checking the bit and applying it on request
+ * issue path.
+ */
+void ioc_cgroup_changed(struct io_context *ioc)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&ioc->lock, flags);
+ ioc_set_changed(ioc, ICQ_CGROUP_CHANGED);
+ spin_unlock_irqrestore(&ioc->lock, flags);
+}
+EXPORT_SYMBOL(ioc_cgroup_changed);
static int __init blk_ioc_init(void)
{
* @lim: the queue_limits structure to reset
*
* Description:
- * Returns a queue_limit struct to its default state. Can be used by
- * stacking drivers like DM that stage table swaps and reuse an
- * existing device queue.
+ * Returns a queue_limit struct to its default state.
*/
void blk_set_default_limits(struct queue_limits *lim)
{
lim->max_integrity_segments = 0;
lim->seg_boundary_mask = BLK_SEG_BOUNDARY_MASK;
lim->max_segment_size = BLK_MAX_SEGMENT_SIZE;
- lim->max_sectors = BLK_DEF_MAX_SECTORS;
- lim->max_hw_sectors = INT_MAX;
+ lim->max_sectors = lim->max_hw_sectors = BLK_SAFE_MAX_SECTORS;
lim->max_discard_sectors = 0;
lim->discard_granularity = 0;
lim->discard_alignment = 0;
lim->discard_misaligned = 0;
- lim->discard_zeroes_data = 1;
+ lim->discard_zeroes_data = 0;
lim->logical_block_size = lim->physical_block_size = lim->io_min = 512;
lim->bounce_pfn = (unsigned long)(BLK_BOUNCE_ANY >> PAGE_SHIFT);
lim->alignment_offset = 0;
}
EXPORT_SYMBOL(blk_set_default_limits);
+/**
+ * blk_set_stacking_limits - set default limits for stacking devices
+ * @lim: the queue_limits structure to reset
+ *
+ * Description:
+ * Returns a queue_limit struct to its default state. Should be used
+ * by stacking drivers like DM that have no internal limits.
+ */
+void blk_set_stacking_limits(struct queue_limits *lim)
+{
+ blk_set_default_limits(lim);
+
+ /* Inherit limits from component devices */
+ lim->discard_zeroes_data = 1;
+ lim->max_segments = USHRT_MAX;
+ lim->max_hw_sectors = UINT_MAX;
+
+ lim->max_sectors = BLK_DEF_MAX_SECTORS;
+}
+EXPORT_SYMBOL(blk_set_stacking_limits);
+
/**
* blk_queue_make_request - define an alternate make_request function for a device
* @q: the request queue for the device to be affected
q->nr_batching = BLK_BATCH_REQ;
blk_set_default_limits(&q->limits);
- blk_queue_max_hw_sectors(q, BLK_SAFE_MAX_SECTORS);
- q->limits.discard_zeroes_data = 0;
/*
* by default assume old behaviour and bounce for any highmem page
if (!entry->show)
return -EIO;
mutex_lock(&q->sysfs_lock);
- if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
+ if (blk_queue_dead(q)) {
mutex_unlock(&q->sysfs_lock);
return -ENOENT;
}
q = container_of(kobj, struct request_queue, kobj);
mutex_lock(&q->sysfs_lock);
- if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)) {
+ if (blk_queue_dead(q)) {
mutex_unlock(&q->sysfs_lock);
return -ENOENT;
}
blk_sync_queue(q);
- if (q->elevator)
+ if (q->elevator) {
+ spin_lock_irq(q->queue_lock);
+ ioc_clear_queue(q);
+ spin_unlock_irq(q->queue_lock);
elevator_exit(q->elevator);
+ }
blk_throtl_exit(q);
blk_trace_shutdown(q);
bdi_destroy(&q->backing_dev_info);
+
+ ida_simple_remove(&blk_queue_ida, q->id);
kmem_cache_free(blk_requestq_cachep, q);
}
struct request_queue *q = td->queue;
/* no throttling for dead queue */
- if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)))
+ if (unlikely(blk_queue_dead(q)))
return NULL;
rcu_read_lock();
spin_lock_irq(q->queue_lock);
/* Make sure @q is still alive */
- if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) {
+ if (unlikely(blk_queue_dead(q))) {
kfree(tg);
return NULL;
}
#ifndef BLK_INTERNAL_H
#define BLK_INTERNAL_H
+#include <linux/idr.h>
+
/* Amount of time in which a process may batch requests */
#define BLK_BATCH_TIME (HZ/50UL)
extern struct kmem_cache *blk_requestq_cachep;
extern struct kobj_type blk_queue_ktype;
+extern struct ida blk_queue_ida;
+
+static inline void __blk_get_queue(struct request_queue *q)
+{
+ kobject_get(&q->kobj);
+}
void init_request_from_bio(struct request *req, struct bio *bio);
void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
q->flush_queue_delayed = 1;
return NULL;
}
- if (test_bit(QUEUE_FLAG_DEAD, &q->queue_flags) ||
- !q->elevator->ops->elevator_dispatch_fn(q, 0))
+ if (unlikely(blk_queue_dead(q)) ||
+ !q->elevator->type->ops.elevator_dispatch_fn(q, 0))
return NULL;
}
}
{
struct elevator_queue *e = q->elevator;
- if (e->ops->elevator_activate_req_fn)
- e->ops->elevator_activate_req_fn(q, rq);
+ if (e->type->ops.elevator_activate_req_fn)
+ e->type->ops.elevator_activate_req_fn(q, rq);
}
static inline void elv_deactivate_rq(struct request_queue *q, struct request *rq)
{
struct elevator_queue *e = q->elevator;
- if (e->ops->elevator_deactivate_req_fn)
- e->ops->elevator_deactivate_req_fn(q, rq);
+ if (e->type->ops.elevator_deactivate_req_fn)
+ e->type->ops.elevator_deactivate_req_fn(q, rq);
}
#ifdef CONFIG_FAIL_IO_TIMEOUT
}
#endif
-struct io_context *current_io_context(gfp_t gfp_flags, int node);
-
int ll_back_merge_fn(struct request_queue *q, struct request *req,
struct bio *bio);
int ll_front_merge_fn(struct request_queue *q, struct request *req,
(rq->cmd_flags & REQ_DISCARD));
}
+/*
+ * Internal io_context interface
+ */
+void get_io_context(struct io_context *ioc);
+struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);
+struct io_cq *ioc_create_icq(struct request_queue *q, gfp_t gfp_mask);
+void ioc_clear_queue(struct request_queue *q);
+
+void create_io_context_slowpath(struct task_struct *task, gfp_t gfp_mask,
+ int node);
+
+/**
+ * create_io_context - try to create task->io_context
+ * @task: target task
+ * @gfp_mask: allocation mask
+ * @node: allocation node
+ *
+ * If @task->io_context is %NULL, allocate a new io_context and install it.
+ * Returns the current @task->io_context which may be %NULL if allocation
+ * failed.
+ *
+ * Note that this function can't be called with IRQ disabled because
+ * task_lock which protects @task->io_context is IRQ-unsafe.
+ */
+static inline struct io_context *create_io_context(struct task_struct *task,
+ gfp_t gfp_mask, int node)
+{
+ WARN_ON_ONCE(irqs_disabled());
+ if (unlikely(!task->io_context))
+ create_io_context_slowpath(task, gfp_mask, node);
+ return task->io_context;
+}
+
+/*
+ * Internal throttling interface
+ */
#ifdef CONFIG_BLK_DEV_THROTTLING
extern bool blk_throtl_bio(struct request_queue *q, struct bio *bio);
extern void blk_throtl_drain(struct request_queue *q);
struct file *file)
{
struct bsg_device *bd;
- int ret;
#ifdef BSG_DEBUG
unsigned char buf[32];
#endif
- ret = blk_get_queue(rq);
- if (ret)
+ if (!blk_get_queue(rq))
return ERR_PTR(-ENXIO);
bd = bsg_alloc_device();
#include <linux/rbtree.h>
#include <linux/ioprio.h>
#include <linux/blktrace_api.h>
+#include "blk.h"
#include "cfq.h"
/*
#define CFQQ_SECT_THR_NONROT (sector_t)(2 * 32)
#define CFQQ_SEEKY(cfqq) (hweight32(cfqq->seek_history) > 32/8)
-#define RQ_CIC(rq) \
- ((struct cfq_io_context *) (rq)->elevator_private[0])
-#define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elevator_private[1])
-#define RQ_CFQG(rq) (struct cfq_group *) ((rq)->elevator_private[2])
+#define RQ_CIC(rq) icq_to_cic((rq)->elv.icq)
+#define RQ_CFQQ(rq) (struct cfq_queue *) ((rq)->elv.priv[0])
+#define RQ_CFQG(rq) (struct cfq_group *) ((rq)->elv.priv[1])
static struct kmem_cache *cfq_pool;
-static struct kmem_cache *cfq_ioc_pool;
-
-static DEFINE_PER_CPU(unsigned long, cfq_ioc_count);
-static struct completion *ioc_gone;
-static DEFINE_SPINLOCK(ioc_gone_lock);
-
-static DEFINE_SPINLOCK(cic_index_lock);
-static DEFINE_IDA(cic_index_ida);
#define CFQ_PRIO_LISTS IOPRIO_BE_NR
#define cfq_class_idle(cfqq) ((cfqq)->ioprio_class == IOPRIO_CLASS_IDLE)
#define sample_valid(samples) ((samples) > 80)
#define rb_entry_cfqg(node) rb_entry((node), struct cfq_group, rb_node)
+struct cfq_ttime {
+ unsigned long last_end_request;
+
+ unsigned long ttime_total;
+ unsigned long ttime_samples;
+ unsigned long ttime_mean;
+};
+
/*
* Most of our rbtree usage is for sorting with min extraction, so
* if we cache the leftmost node we don't have to walk down the tree
struct cfq_ttime ttime;
};
+struct cfq_io_cq {
+ struct io_cq icq; /* must be the first member */
+ struct cfq_queue *cfqq[2];
+ struct cfq_ttime ttime;
+};
+
/*
* Per block device queue structure
*/
struct work_struct unplug_work;
struct cfq_queue *active_queue;
- struct cfq_io_context *active_cic;
+ struct cfq_io_cq *active_cic;
/*
* async queue for each priority case
unsigned int cfq_group_idle;
unsigned int cfq_latency;
- unsigned int cic_index;
- struct list_head cic_list;
-
/*
* Fallback dummy cfqq for extreme OOM conditions
*/
static void cfq_dispatch_insert(struct request_queue *, struct request *);
static struct cfq_queue *cfq_get_queue(struct cfq_data *, bool,
struct io_context *, gfp_t);
-static struct cfq_io_context *cfq_cic_lookup(struct cfq_data *,
- struct io_context *);
-static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_context *cic,
- bool is_sync)
+static inline struct cfq_io_cq *icq_to_cic(struct io_cq *icq)
{
- return cic->cfqq[is_sync];
+ /* cic->icq is the first member, %NULL will convert to %NULL */
+ return container_of(icq, struct cfq_io_cq, icq);
}
-static inline void cic_set_cfqq(struct cfq_io_context *cic,
- struct cfq_queue *cfqq, bool is_sync)
+static inline struct cfq_io_cq *cfq_cic_lookup(struct cfq_data *cfqd,
+ struct io_context *ioc)
{
- cic->cfqq[is_sync] = cfqq;
+ if (ioc)
+ return icq_to_cic(ioc_lookup_icq(ioc, cfqd->queue));
+ return NULL;
}
-#define CIC_DEAD_KEY 1ul
-#define CIC_DEAD_INDEX_SHIFT 1
-
-static inline void *cfqd_dead_key(struct cfq_data *cfqd)
+static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_cq *cic, bool is_sync)
{
- return (void *)(cfqd->cic_index << CIC_DEAD_INDEX_SHIFT | CIC_DEAD_KEY);
+ return cic->cfqq[is_sync];
}
-static inline struct cfq_data *cic_to_cfqd(struct cfq_io_context *cic)
+static inline void cic_set_cfqq(struct cfq_io_cq *cic, struct cfq_queue *cfqq,
+ bool is_sync)
{
- struct cfq_data *cfqd = cic->key;
-
- if (unlikely((unsigned long) cfqd & CIC_DEAD_KEY))
- return NULL;
+ cic->cfqq[is_sync] = cfqq;
+}
- return cfqd;
+static inline struct cfq_data *cic_to_cfqd(struct cfq_io_cq *cic)
+{
+ return cic->icq.q->elevator->elevator_data;
}
/*
cfq_find_rq_fmerge(struct cfq_data *cfqd, struct bio *bio)
{
struct task_struct *tsk = current;
- struct cfq_io_context *cic;
+ struct cfq_io_cq *cic;
struct cfq_queue *cfqq;
cic = cfq_cic_lookup(cfqd, tsk->io_context);
struct bio *bio)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
- struct cfq_io_context *cic;
+ struct cfq_io_cq *cic;
struct cfq_queue *cfqq;
/*
return false;
/*
- * Lookup the cfqq that this bio will be queued with. Allow
- * merge only if rq is queued there.
+ * Lookup the cfqq that this bio will be queued with and allow
+ * merge only if rq is queued there. This function can be called
+ * from plug merge without queue_lock. In such cases, ioc of @rq
+ * and %current are guaranteed to be equal. Avoid lookup which
+ * requires queue_lock by using @rq's cic.
*/
- cic = cfq_cic_lookup(cfqd, current->io_context);
- if (!cic)
- return false;
+ if (current->io_context == RQ_CIC(rq)->icq.ioc) {
+ cic = RQ_CIC(rq);
+ } else {
+ cic = cfq_cic_lookup(cfqd, current->io_context);
+ if (!cic)
+ return false;
+ }
cfqq = cic_to_cfqq(cic, cfq_bio_sync(bio));
return cfqq == RQ_CFQQ(rq);
cfqd->active_queue = NULL;
if (cfqd->active_cic) {
- put_io_context(cfqd->active_cic->ioc);
+ put_io_context(cfqd->active_cic->icq.ioc, cfqd->queue);
cfqd->active_cic = NULL;
}
}
static void cfq_arm_slice_timer(struct cfq_data *cfqd)
{
struct cfq_queue *cfqq = cfqd->active_queue;
- struct cfq_io_context *cic;
+ struct cfq_io_cq *cic;
unsigned long sl, group_idle = 0;
/*
* task has exited, don't wait
*/
cic = cfqd->active_cic;
- if (!cic || !atomic_read(&cic->ioc->nr_tasks))
+ if (!cic || !atomic_read(&cic->icq.ioc->nr_tasks))
return;
/*
cfq_dispatch_insert(cfqd->queue, rq);
if (!cfqd->active_cic) {
- struct cfq_io_context *cic = RQ_CIC(rq);
+ struct cfq_io_cq *cic = RQ_CIC(rq);
- atomic_long_inc(&cic->ioc->refcount);
+ atomic_long_inc(&cic->icq.ioc->refcount);
cfqd->active_cic = cic;
}
cfq_put_cfqg(cfqg);
}
-/*
- * Call func for each cic attached to this ioc.
- */
-static void
-call_for_each_cic(struct io_context *ioc,
- void (*func)(struct io_context *, struct cfq_io_context *))
-{
- struct cfq_io_context *cic;
- struct hlist_node *n;
-
- rcu_read_lock();
-
- hlist_for_each_entry_rcu(cic, n, &ioc->cic_list, cic_list)
- func(ioc, cic);
-
- rcu_read_unlock();
-}
-
-static void cfq_cic_free_rcu(struct rcu_head *head)
-{
- struct cfq_io_context *cic;
-
- cic = container_of(head, struct cfq_io_context, rcu_head);
-
- kmem_cache_free(cfq_ioc_pool, cic);
- elv_ioc_count_dec(cfq_ioc_count);
-
- if (ioc_gone) {
- /*
- * CFQ scheduler is exiting, grab exit lock and check
- * the pending io context count. If it hits zero,
- * complete ioc_gone and set it back to NULL
- */
- spin_lock(&ioc_gone_lock);
- if (ioc_gone && !elv_ioc_count_read(cfq_ioc_count)) {
- complete(ioc_gone);
- ioc_gone = NULL;
- }
- spin_unlock(&ioc_gone_lock);
- }
-}
-
-static void cfq_cic_free(struct cfq_io_context *cic)
-{
- call_rcu(&cic->rcu_head, cfq_cic_free_rcu);
-}
-
-static void cic_free_func(struct io_context *ioc, struct cfq_io_context *cic)
-{
- unsigned long flags;
- unsigned long dead_key = (unsigned long) cic->key;
-
- BUG_ON(!(dead_key & CIC_DEAD_KEY));
-
- spin_lock_irqsave(&ioc->lock, flags);
- radix_tree_delete(&ioc->radix_root, dead_key >> CIC_DEAD_INDEX_SHIFT);
- hlist_del_rcu(&cic->cic_list);
- spin_unlock_irqrestore(&ioc->lock, flags);
-
- cfq_cic_free(cic);
-}
-
-/*
- * Must be called with rcu_read_lock() held or preemption otherwise disabled.
- * Only two callers of this - ->dtor() which is called with the rcu_read_lock(),
- * and ->trim() which is called with the task lock held
- */
-static void cfq_free_io_context(struct io_context *ioc)
-{
- /*
- * ioc->refcount is zero here, or we are called from elv_unregister(),
- * so no more cic's are allowed to be linked into this ioc. So it
- * should be ok to iterate over the known list, we will see all cic's
- * since no new ones are added.
- */
- call_for_each_cic(ioc, cic_free_func);
-}
-
static void cfq_put_cooperator(struct cfq_queue *cfqq)
{
struct cfq_queue *__cfqq, *next;
cfq_put_queue(cfqq);
}
-static void __cfq_exit_single_io_context(struct cfq_data *cfqd,
- struct cfq_io_context *cic)
+static void cfq_init_icq(struct io_cq *icq)
{
- struct io_context *ioc = cic->ioc;
-
- list_del_init(&cic->queue_list);
+ struct cfq_io_cq *cic = icq_to_cic(icq);
- /*
- * Make sure dead mark is seen for dead queues
- */
- smp_wmb();
- cic->key = cfqd_dead_key(cfqd);
+ cic->ttime.last_end_request = jiffies;
+}
- rcu_read_lock();
- if (rcu_dereference(ioc->ioc_data) == cic) {
- rcu_read_unlock();
- spin_lock(&ioc->lock);
- rcu_assign_pointer(ioc->ioc_data, NULL);
- spin_unlock(&ioc->lock);
- } else
- rcu_read_unlock();
+static void cfq_exit_icq(struct io_cq *icq)
+{
+ struct cfq_io_cq *cic = icq_to_cic(icq);
+ struct cfq_data *cfqd = cic_to_cfqd(cic);
if (cic->cfqq[BLK_RW_ASYNC]) {
cfq_exit_cfqq(cfqd, cic->cfqq[BLK_RW_ASYNC]);
}
}
-static void cfq_exit_single_io_context(struct io_context *ioc,
- struct cfq_io_context *cic)
-{
- struct cfq_data *cfqd = cic_to_cfqd(cic);
-
- if (cfqd) {
- struct request_queue *q = cfqd->queue;
- unsigned long flags;
-
- spin_lock_irqsave(q->queue_lock, flags);
-
- /*
- * Ensure we get a fresh copy of the ->key to prevent
- * race between exiting task and queue
- */
- smp_read_barrier_depends();
- if (cic->key == cfqd)
- __cfq_exit_single_io_context(cfqd, cic);
-
- spin_unlock_irqrestore(q->queue_lock, flags);
- }
-}
-
-/*
- * The process that ioc belongs to has exited, we need to clean up
- * and put the internal structures we have that belongs to that process.
- */
-static void cfq_exit_io_context(struct io_context *ioc)
-{
- call_for_each_cic(ioc, cfq_exit_single_io_context);
-}
-
-static struct cfq_io_context *
-cfq_alloc_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
-{
- struct cfq_io_context *cic;
-
- cic = kmem_cache_alloc_node(cfq_ioc_pool, gfp_mask | __GFP_ZERO,
- cfqd->queue->node);
- if (cic) {
- cic->ttime.last_end_request = jiffies;
- INIT_LIST_HEAD(&cic->queue_list);
- INIT_HLIST_NODE(&cic->cic_list);
- cic->dtor = cfq_free_io_context;
- cic->exit = cfq_exit_io_context;
- elv_ioc_count_inc(cfq_ioc_count);
- }
-
- return cic;
-}
-
static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc)
{
struct task_struct *tsk = current;
cfq_clear_cfqq_prio_changed(cfqq);
}
-static void changed_ioprio(struct io_context *ioc, struct cfq_io_context *cic)
+static void changed_ioprio(struct cfq_io_cq *cic)
{
struct cfq_data *cfqd = cic_to_cfqd(cic);
struct cfq_queue *cfqq;
- unsigned long flags;
if (unlikely(!cfqd))
return;
- spin_lock_irqsave(cfqd->queue->queue_lock, flags);
-
cfqq = cic->cfqq[BLK_RW_ASYNC];
if (cfqq) {
struct cfq_queue *new_cfqq;
- new_cfqq = cfq_get_queue(cfqd, BLK_RW_ASYNC, cic->ioc,
+ new_cfqq = cfq_get_queue(cfqd, BLK_RW_ASYNC, cic->icq.ioc,
GFP_ATOMIC);
if (new_cfqq) {
cic->cfqq[BLK_RW_ASYNC] = new_cfqq;
cfqq = cic->cfqq[BLK_RW_SYNC];
if (cfqq)
cfq_mark_cfqq_prio_changed(cfqq);
-
- spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
-}
-
-static void cfq_ioc_set_ioprio(struct io_context *ioc)
-{
- call_for_each_cic(ioc, changed_ioprio);
- ioc->ioprio_changed = 0;
}
static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
}
#ifdef CONFIG_CFQ_GROUP_IOSCHED
-static void changed_cgroup(struct io_context *ioc, struct cfq_io_context *cic)
+static void changed_cgroup(struct cfq_io_cq *cic)
{
struct cfq_queue *sync_cfqq = cic_to_cfqq(cic, 1);
struct cfq_data *cfqd = cic_to_cfqd(cic);
- unsigned long flags;
struct request_queue *q;
if (unlikely(!cfqd))
q = cfqd->queue;
- spin_lock_irqsave(q->queue_lock, flags);
-
if (sync_cfqq) {
/*
* Drop reference to sync queue. A new sync queue will be
cic_set_cfqq(cic, NULL, 1);
cfq_put_queue(sync_cfqq);
}
-
- spin_unlock_irqrestore(q->queue_lock, flags);
-}
-
-static void cfq_ioc_set_cgroup(struct io_context *ioc)
-{
- call_for_each_cic(ioc, changed_cgroup);
- ioc->cgroup_changed = 0;
}
#endif /* CONFIG_CFQ_GROUP_IOSCHED */
struct io_context *ioc, gfp_t gfp_mask)
{
struct cfq_queue *cfqq, *new_cfqq = NULL;
- struct cfq_io_context *cic;
+ struct cfq_io_cq *cic;
struct cfq_group *cfqg;
retry:
return cfqq;
}
-/*
- * We drop cfq io contexts lazily, so we may find a dead one.
- */
-static void
-cfq_drop_dead_cic(struct cfq_data *cfqd, struct io_context *ioc,
- struct cfq_io_context *cic)
-{
- unsigned long flags;
-
- WARN_ON(!list_empty(&cic->queue_list));
- BUG_ON(cic->key != cfqd_dead_key(cfqd));
-
- spin_lock_irqsave(&ioc->lock, flags);
-
- BUG_ON(rcu_dereference_check(ioc->ioc_data,
- lockdep_is_held(&ioc->lock)) == cic);
-
- radix_tree_delete(&ioc->radix_root, cfqd->cic_index);
- hlist_del_rcu(&cic->cic_list);
- spin_unlock_irqrestore(&ioc->lock, flags);
-
- cfq_cic_free(cic);
-}
-
-static struct cfq_io_context *
-cfq_cic_lookup(struct cfq_data *cfqd, struct io_context *ioc)
-{
- struct cfq_io_context *cic;
- unsigned long flags;
-
- if (unlikely(!ioc))
- return NULL;
-
- rcu_read_lock();
-
- /*
- * we maintain a last-hit cache, to avoid browsing over the tree
- */
- cic = rcu_dereference(ioc->ioc_data);
- if (cic && cic->key == cfqd) {
- rcu_read_unlock();
- return cic;
- }
-
- do {
- cic = radix_tree_lookup(&ioc->radix_root, cfqd->cic_index);
- rcu_read_unlock();
- if (!cic)
- break;
- if (unlikely(cic->key != cfqd)) {
- cfq_drop_dead_cic(cfqd, ioc, cic);
- rcu_read_lock();
- continue;
- }
-
- spin_lock_irqsave(&ioc->lock, flags);
- rcu_assign_pointer(ioc->ioc_data, cic);
- spin_unlock_irqrestore(&ioc->lock, flags);
- break;
- } while (1);
-
- return cic;
-}
-
-/*
- * Add cic into ioc, using cfqd as the search key. This enables us to lookup
- * the process specific cfq io context when entered from the block layer.
- * Also adds the cic to a per-cfqd list, used when this queue is removed.
- */
-static int cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc,
- struct cfq_io_context *cic, gfp_t gfp_mask)
-{
- unsigned long flags;
- int ret;
-
- ret = radix_tree_preload(gfp_mask);
- if (!ret) {
- cic->ioc = ioc;
- cic->key = cfqd;
-
- spin_lock_irqsave(&ioc->lock, flags);
- ret = radix_tree_insert(&ioc->radix_root,
- cfqd->cic_index, cic);
- if (!ret)
- hlist_add_head_rcu(&cic->cic_list, &ioc->cic_list);
- spin_unlock_irqrestore(&ioc->lock, flags);
-
- radix_tree_preload_end();
-
- if (!ret) {
- spin_lock_irqsave(cfqd->queue->queue_lock, flags);
- list_add(&cic->queue_list, &cfqd->cic_list);
- spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
- }
- }
-
- if (ret && ret != -EEXIST)
- printk(KERN_ERR "cfq: cic link failed!\n");
-
- return ret;
-}
-
-/*
- * Setup general io context and cfq io context. There can be several cfq
- * io contexts per general io context, if this process is doing io to more
- * than one device managed by cfq.
- */
-static struct cfq_io_context *
-cfq_get_io_context(struct cfq_data *cfqd, gfp_t gfp_mask)
-{
- struct io_context *ioc = NULL;
- struct cfq_io_context *cic;
- int ret;
-
- might_sleep_if(gfp_mask & __GFP_WAIT);
-
- ioc = get_io_context(gfp_mask, cfqd->queue->node);
- if (!ioc)
- return NULL;
-
-retry:
- cic = cfq_cic_lookup(cfqd, ioc);
- if (cic)
- goto out;
-
- cic = cfq_alloc_io_context(cfqd, gfp_mask);
- if (cic == NULL)
- goto err;
-
- ret = cfq_cic_link(cfqd, ioc, cic, gfp_mask);
- if (ret == -EEXIST) {
- /* someone has linked cic to ioc already */
- cfq_cic_free(cic);
- goto retry;
- } else if (ret)
- goto err_free;
-
-out:
- smp_read_barrier_depends();
- if (unlikely(ioc->ioprio_changed))
- cfq_ioc_set_ioprio(ioc);
-
-#ifdef CONFIG_CFQ_GROUP_IOSCHED
- if (unlikely(ioc->cgroup_changed))
- cfq_ioc_set_cgroup(ioc);
-#endif
- return cic;
-err_free:
- cfq_cic_free(cic);
-err:
- put_io_context(ioc);
- return NULL;
-}
-
static void
__cfq_update_io_thinktime(struct cfq_ttime *ttime, unsigned long slice_idle)
{
static void
cfq_update_io_thinktime(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- struct cfq_io_context *cic)
+ struct cfq_io_cq *cic)
{
if (cfq_cfqq_sync(cfqq)) {
__cfq_update_io_thinktime(&cic->ttime, cfqd->cfq_slice_idle);
*/
static void
cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
- struct cfq_io_context *cic)
+ struct cfq_io_cq *cic)
{
int old_idle, enable_idle;
if (cfqq->next_rq && (cfqq->next_rq->cmd_flags & REQ_NOIDLE))
enable_idle = 0;
- else if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle ||
- (!cfq_cfqq_deep(cfqq) && CFQQ_SEEKY(cfqq)))
+ else if (!atomic_read(&cic->icq.ioc->nr_tasks) ||
+ !cfqd->cfq_slice_idle ||
+ (!cfq_cfqq_deep(cfqq) && CFQQ_SEEKY(cfqq)))
enable_idle = 0;
else if (sample_valid(cic->ttime.ttime_samples)) {
if (cic->ttime.ttime_mean > cfqd->cfq_slice_idle)
cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
struct request *rq)
{
- struct cfq_io_context *cic = RQ_CIC(rq);
+ struct cfq_io_cq *cic = RQ_CIC(rq);
cfqd->rq_queued++;
if (rq->cmd_flags & REQ_PRIO)
struct cfq_queue *cfqq = RQ_CFQQ(rq);
cfq_log_cfqq(cfqd, cfqq, "insert_request");
- cfq_init_prio_data(cfqq, RQ_CIC(rq)->ioc);
+ cfq_init_prio_data(cfqq, RQ_CIC(rq)->icq.ioc);
rq_set_fifo_time(rq, jiffies + cfqd->cfq_fifo_expire[rq_is_sync(rq)]);
list_add_tail(&rq->queuelist, &cfqq->fifo);
static bool cfq_should_wait_busy(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
- struct cfq_io_context *cic = cfqd->active_cic;
+ struct cfq_io_cq *cic = cfqd->active_cic;
/* If the queue already has requests, don't wait */
if (!RB_EMPTY_ROOT(&cfqq->sort_list))
{
struct cfq_data *cfqd = q->elevator->elevator_data;
struct task_struct *tsk = current;
- struct cfq_io_context *cic;
+ struct cfq_io_cq *cic;
struct cfq_queue *cfqq;
/*
cfqq = cic_to_cfqq(cic, rw_is_sync(rw));
if (cfqq) {
- cfq_init_prio_data(cfqq, cic->ioc);
+ cfq_init_prio_data(cfqq, cic->icq.ioc);
return __cfq_may_queue(cfqq);
}
BUG_ON(!cfqq->allocated[rw]);
cfqq->allocated[rw]--;
- put_io_context(RQ_CIC(rq)->ioc);
-
- rq->elevator_private[0] = NULL;
- rq->elevator_private[1] = NULL;
-
/* Put down rq reference on cfqg */
cfq_put_cfqg(RQ_CFQG(rq));
- rq->elevator_private[2] = NULL;
+ rq->elv.priv[0] = NULL;
+ rq->elv.priv[1] = NULL;
cfq_put_queue(cfqq);
}
}
static struct cfq_queue *
-cfq_merge_cfqqs(struct cfq_data *cfqd, struct cfq_io_context *cic,
+cfq_merge_cfqqs(struct cfq_data *cfqd, struct cfq_io_cq *cic,
struct cfq_queue *cfqq)
{
cfq_log_cfqq(cfqd, cfqq, "merging with queue %p", cfqq->new_cfqq);
* was the last process referring to said cfqq.
*/
static struct cfq_queue *
-split_cfqq(struct cfq_io_context *cic, struct cfq_queue *cfqq)
+split_cfqq(struct cfq_io_cq *cic, struct cfq_queue *cfqq)
{
if (cfqq_process_refs(cfqq) == 1) {
cfqq->pid = current->pid;
cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
- struct cfq_io_context *cic;
+ struct cfq_io_cq *cic = icq_to_cic(rq->elv.icq);
const int rw = rq_data_dir(rq);
const bool is_sync = rq_is_sync(rq);
struct cfq_queue *cfqq;
- unsigned long flags;
might_sleep_if(gfp_mask & __GFP_WAIT);
- cic = cfq_get_io_context(cfqd, gfp_mask);
-
- spin_lock_irqsave(q->queue_lock, flags);
+ spin_lock_irq(q->queue_lock);
- if (!cic)
- goto queue_fail;
+ /* handle changed notifications */
+ if (unlikely(cic->icq.changed)) {
+ if (test_and_clear_bit(ICQ_IOPRIO_CHANGED, &cic->icq.changed))
+ changed_ioprio(cic);
+#ifdef CONFIG_CFQ_GROUP_IOSCHED
+ if (test_and_clear_bit(ICQ_CGROUP_CHANGED, &cic->icq.changed))
+ changed_cgroup(cic);
+#endif
+ }
new_queue:
cfqq = cic_to_cfqq(cic, is_sync);
if (!cfqq || cfqq == &cfqd->oom_cfqq) {
- cfqq = cfq_get_queue(cfqd, is_sync, cic->ioc, gfp_mask);
+ cfqq = cfq_get_queue(cfqd, is_sync, cic->icq.ioc, gfp_mask);
cic_set_cfqq(cic, cfqq, is_sync);
} else {
/*
cfqq->allocated[rw]++;
cfqq->ref++;
- rq->elevator_private[0] = cic;
- rq->elevator_private[1] = cfqq;
- rq->elevator_private[2] = cfq_ref_get_cfqg(cfqq->cfqg);
- spin_unlock_irqrestore(q->queue_lock, flags);
+ rq->elv.priv[0] = cfqq;
+ rq->elv.priv[1] = cfq_ref_get_cfqg(cfqq->cfqg);
+ spin_unlock_irq(q->queue_lock);
return 0;
-
-queue_fail:
- cfq_schedule_dispatch(cfqd);
- spin_unlock_irqrestore(q->queue_lock, flags);
- cfq_log(cfqd, "set_request fail");
- return 1;
}
static void cfq_kick_queue(struct work_struct *work)
if (cfqd->active_queue)
__cfq_slice_expired(cfqd, cfqd->active_queue, 0);
- while (!list_empty(&cfqd->cic_list)) {
- struct cfq_io_context *cic = list_entry(cfqd->cic_list.next,
- struct cfq_io_context,
- queue_list);
-
- __cfq_exit_single_io_context(cfqd, cic);
- }
-
cfq_put_async_queues(cfqd);
cfq_release_cfq_groups(cfqd);
cfq_shutdown_timer_wq(cfqd);
- spin_lock(&cic_index_lock);
- ida_remove(&cic_index_ida, cfqd->cic_index);
- spin_unlock(&cic_index_lock);
-
/*
* Wait for cfqg->blkg->key accessors to exit their grace periods.
* Do this wait only if there are other unlinked groups out
kfree(cfqd);
}
-static int cfq_alloc_cic_index(void)
-{
- int index, error;
-
- do {
- if (!ida_pre_get(&cic_index_ida, GFP_KERNEL))
- return -ENOMEM;
-
- spin_lock(&cic_index_lock);
- error = ida_get_new(&cic_index_ida, &index);
- spin_unlock(&cic_index_lock);
- if (error && error != -EAGAIN)
- return error;
- } while (error);
-
- return index;
-}
-
static void *cfq_init_queue(struct request_queue *q)
{
struct cfq_data *cfqd;
struct cfq_group *cfqg;
struct cfq_rb_root *st;
- i = cfq_alloc_cic_index();
- if (i < 0)
- return NULL;
-
cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node);
- if (!cfqd) {
- spin_lock(&cic_index_lock);
- ida_remove(&cic_index_ida, i);
- spin_unlock(&cic_index_lock);
+ if (!cfqd)
return NULL;
- }
-
- /*
- * Don't need take queue_lock in the routine, since we are
- * initializing the ioscheduler, and nobody is using cfqd
- */
- cfqd->cic_index = i;
/* Init root service tree */
cfqd->grp_service_tree = CFQ_RB_ROOT;
if (blkio_alloc_blkg_stats(&cfqg->blkg)) {
kfree(cfqg);
-
- spin_lock(&cic_index_lock);
- ida_remove(&cic_index_ida, cfqd->cic_index);
- spin_unlock(&cic_index_lock);
-
kfree(cfqd);
return NULL;
}
cfqd->oom_cfqq.ref++;
cfq_link_cfqq_cfqg(&cfqd->oom_cfqq, &cfqd->root_group);
- INIT_LIST_HEAD(&cfqd->cic_list);
-
cfqd->queue = q;
init_timer(&cfqd->idle_slice_timer);
return cfqd;
}
-static void cfq_slab_kill(void)
-{
- /*
- * Caller already ensured that pending RCU callbacks are completed,
- * so we should have no busy allocations at this point.
- */
- if (cfq_pool)
- kmem_cache_destroy(cfq_pool);
- if (cfq_ioc_pool)
- kmem_cache_destroy(cfq_ioc_pool);
-}
-
-static int __init cfq_slab_setup(void)
-{
- cfq_pool = KMEM_CACHE(cfq_queue, 0);
- if (!cfq_pool)
- goto fail;
-
- cfq_ioc_pool = KMEM_CACHE(cfq_io_context, 0);
- if (!cfq_ioc_pool)
- goto fail;
-
- return 0;
-fail:
- cfq_slab_kill();
- return -ENOMEM;
-}
-
/*
* sysfs parts below -->
*/
.elevator_completed_req_fn = cfq_completed_request,
.elevator_former_req_fn = elv_rb_former_request,
.elevator_latter_req_fn = elv_rb_latter_request,
+ .elevator_init_icq_fn = cfq_init_icq,
+ .elevator_exit_icq_fn = cfq_exit_icq,
.elevator_set_req_fn = cfq_set_request,
.elevator_put_req_fn = cfq_put_request,
.elevator_may_queue_fn = cfq_may_queue,
.elevator_init_fn = cfq_init_queue,
.elevator_exit_fn = cfq_exit_queue,
- .trim = cfq_free_io_context,
},
+ .icq_size = sizeof(struct cfq_io_cq),
+ .icq_align = __alignof__(struct cfq_io_cq),
.elevator_attrs = cfq_attrs,
- .elevator_name = "cfq",
+ .elevator_name = "cfq",
.elevator_owner = THIS_MODULE,
};
static int __init cfq_init(void)
{
+ int ret;
+
/*
* could be 0 on HZ < 1000 setups
*/
#else
cfq_group_idle = 0;
#endif
- if (cfq_slab_setup())
+ cfq_pool = KMEM_CACHE(cfq_queue, 0);
+ if (!cfq_pool)
return -ENOMEM;
- elv_register(&iosched_cfq);
+ ret = elv_register(&iosched_cfq);
+ if (ret) {
+ kmem_cache_destroy(cfq_pool);
+ return ret;
+ }
+
blkio_policy_register(&blkio_policy_cfq);
return 0;
static void __exit cfq_exit(void)
{
- DECLARE_COMPLETION_ONSTACK(all_gone);
blkio_policy_unregister(&blkio_policy_cfq);
elv_unregister(&iosched_cfq);
- ioc_gone = &all_gone;
- /* ioc_gone's update must be visible before reading ioc_count */
- smp_wmb();
-
- /*
- * this also protects us from entering cfq_slab_kill() with
- * pending RCU callbacks
- */
- if (elv_ioc_count_read(cfq_ioc_count))
- wait_for_completion(&all_gone);
- ida_destroy(&cic_index_ida);
- cfq_slab_kill();
+ kmem_cache_destroy(cfq_pool);
}
module_init(cfq_init);
case BLKSECTGET:
return compat_put_ushort(arg,
queue_max_sectors(bdev_get_queue(bdev)));
+ case BLKROTATIONAL:
+ return compat_put_ushort(arg,
+ !blk_queue_nonrot(bdev_get_queue(bdev)));
case BLKRASET: /* compatible, but no compat_ptr (!) */
case BLKFRASET:
if (!capable(CAP_SYS_ADMIN))
static int __init deadline_init(void)
{
- elv_register(&iosched_deadline);
-
- return 0;
+ return elv_register(&iosched_deadline);
}
static void __exit deadline_exit(void)
struct request_queue *q = rq->q;
struct elevator_queue *e = q->elevator;
- if (e->ops->elevator_allow_merge_fn)
- return e->ops->elevator_allow_merge_fn(q, rq, bio);
+ if (e->type->ops.elevator_allow_merge_fn)
+ return e->type->ops.elevator_allow_merge_fn(q, rq, bio);
return 1;
}
return e;
}
-static void *elevator_init_queue(struct request_queue *q,
- struct elevator_queue *eq)
+static int elevator_init_queue(struct request_queue *q,
+ struct elevator_queue *eq)
{
- return eq->ops->elevator_init_fn(q);
-}
-
-static void elevator_attach(struct request_queue *q, struct elevator_queue *eq,
- void *data)
-{
- q->elevator = eq;
- eq->elevator_data = data;
+ eq->elevator_data = eq->type->ops.elevator_init_fn(q);
+ if (eq->elevator_data)
+ return 0;
+ return -ENOMEM;
}
static char chosen_elevator[ELV_NAME_MAX];
if (unlikely(!eq))
goto err;
- eq->ops = &e->ops;
- eq->elevator_type = e;
+ eq->type = e;
kobject_init(&eq->kobj, &elv_ktype);
mutex_init(&eq->sysfs_lock);
struct elevator_queue *e;
e = container_of(kobj, struct elevator_queue, kobj);
- elevator_put(e->elevator_type);
+ elevator_put(e->type);
kfree(e->hash);
kfree(e);
}
{
struct elevator_type *e = NULL;
struct elevator_queue *eq;
- void *data;
+ int err;
if (unlikely(q->elevator))
return 0;
if (!eq)
return -ENOMEM;
- data = elevator_init_queue(q, eq);
- if (!data) {
+ err = elevator_init_queue(q, eq);
+ if (err) {
kobject_put(&eq->kobj);
- return -ENOMEM;
+ return err;
}
- elevator_attach(q, eq, data);
+ q->elevator = eq;
return 0;
}
EXPORT_SYMBOL(elevator_init);
void elevator_exit(struct elevator_queue *e)
{
mutex_lock(&e->sysfs_lock);
- if (e->ops->elevator_exit_fn)
- e->ops->elevator_exit_fn(e);
- e->ops = NULL;
+ if (e->type->ops.elevator_exit_fn)
+ e->type->ops.elevator_exit_fn(e);
mutex_unlock(&e->sysfs_lock);
kobject_put(&e->kobj);
return ELEVATOR_BACK_MERGE;
}
- if (e->ops->elevator_merge_fn)
- return e->ops->elevator_merge_fn(q, req, bio);
+ if (e->type->ops.elevator_merge_fn)
+ return e->type->ops.elevator_merge_fn(q, req, bio);
return ELEVATOR_NO_MERGE;
}
{
struct elevator_queue *e = q->elevator;
- if (e->ops->elevator_merged_fn)
- e->ops->elevator_merged_fn(q, rq, type);
+ if (e->type->ops.elevator_merged_fn)
+ e->type->ops.elevator_merged_fn(q, rq, type);
if (type == ELEVATOR_BACK_MERGE)
elv_rqhash_reposition(q, rq);
struct elevator_queue *e = q->elevator;
const int next_sorted = next->cmd_flags & REQ_SORTED;
- if (next_sorted && e->ops->elevator_merge_req_fn)
- e->ops->elevator_merge_req_fn(q, rq, next);
+ if (next_sorted && e->type->ops.elevator_merge_req_fn)
+ e->type->ops.elevator_merge_req_fn(q, rq, next);
elv_rqhash_reposition(q, rq);
{
struct elevator_queue *e = q->elevator;
- if (e->ops->elevator_bio_merged_fn)
- e->ops->elevator_bio_merged_fn(q, rq, bio);
+ if (e->type->ops.elevator_bio_merged_fn)
+ e->type->ops.elevator_bio_merged_fn(q, rq, bio);
}
void elv_requeue_request(struct request_queue *q, struct request *rq)
lockdep_assert_held(q->queue_lock);
- while (q->elevator->ops->elevator_dispatch_fn(q, 1))
+ while (q->elevator->type->ops.elevator_dispatch_fn(q, 1))
;
if (q->nr_sorted && printed++ < 10) {
printk(KERN_ERR "%s: forced dispatching is broken "
"(nr_sorted=%u), please report this\n",
- q->elevator->elevator_type->elevator_name, q->nr_sorted);
+ q->elevator->type->elevator_name, q->nr_sorted);
}
}
* rq cannot be accessed after calling
* elevator_add_req_fn.
*/
- q->elevator->ops->elevator_add_req_fn(q, rq);
+ q->elevator->type->ops.elevator_add_req_fn(q, rq);
break;
case ELEVATOR_INSERT_FLUSH:
{
struct elevator_queue *e = q->elevator;
- if (e->ops->elevator_latter_req_fn)
- return e->ops->elevator_latter_req_fn(q, rq);
+ if (e->type->ops.elevator_latter_req_fn)
+ return e->type->ops.elevator_latter_req_fn(q, rq);
return NULL;
}
{
struct elevator_queue *e = q->elevator;
- if (e->ops->elevator_former_req_fn)
- return e->ops->elevator_former_req_fn(q, rq);
+ if (e->type->ops.elevator_former_req_fn)
+ return e->type->ops.elevator_former_req_fn(q, rq);
return NULL;
}
{
struct elevator_queue *e = q->elevator;
- if (e->ops->elevator_set_req_fn)
- return e->ops->elevator_set_req_fn(q, rq, gfp_mask);
-
- rq->elevator_private[0] = NULL;
+ if (e->type->ops.elevator_set_req_fn)
+ return e->type->ops.elevator_set_req_fn(q, rq, gfp_mask);
return 0;
}
{
struct elevator_queue *e = q->elevator;
- if (e->ops->elevator_put_req_fn)
- e->ops->elevator_put_req_fn(rq);
+ if (e->type->ops.elevator_put_req_fn)
+ e->type->ops.elevator_put_req_fn(rq);
}
int elv_may_queue(struct request_queue *q, int rw)
{
struct elevator_queue *e = q->elevator;
- if (e->ops->elevator_may_queue_fn)
- return e->ops->elevator_may_queue_fn(q, rw);
+ if (e->type->ops.elevator_may_queue_fn)
+ return e->type->ops.elevator_may_queue_fn(q, rw);
return ELV_MQUEUE_MAY;
}
if (blk_account_rq(rq)) {
q->in_flight[rq_is_sync(rq)]--;
if ((rq->cmd_flags & REQ_SORTED) &&
- e->ops->elevator_completed_req_fn)
- e->ops->elevator_completed_req_fn(q, rq);
+ e->type->ops.elevator_completed_req_fn)
+ e->type->ops.elevator_completed_req_fn(q, rq);
}
}
e = container_of(kobj, struct elevator_queue, kobj);
mutex_lock(&e->sysfs_lock);
- error = e->ops ? entry->show(e, page) : -ENOENT;
+ error = e->type ? entry->show(e, page) : -ENOENT;
mutex_unlock(&e->sysfs_lock);
return error;
}
e = container_of(kobj, struct elevator_queue, kobj);
mutex_lock(&e->sysfs_lock);
- error = e->ops ? entry->store(e, page, length) : -ENOENT;
+ error = e->type ? entry->store(e, page, length) : -ENOENT;
mutex_unlock(&e->sysfs_lock);
return error;
}
.release = elevator_release,
};
-int elv_register_queue(struct request_queue *q)
+int __elv_register_queue(struct request_queue *q, struct elevator_queue *e)
{
- struct elevator_queue *e = q->elevator;
int error;
error = kobject_add(&e->kobj, &q->kobj, "%s", "iosched");
if (!error) {
- struct elv_fs_entry *attr = e->elevator_type->elevator_attrs;
+ struct elv_fs_entry *attr = e->type->elevator_attrs;
if (attr) {
while (attr->attr.name) {
if (sysfs_create_file(&e->kobj, &attr->attr))
}
return error;
}
-EXPORT_SYMBOL(elv_register_queue);
-static void __elv_unregister_queue(struct elevator_queue *e)
+int elv_register_queue(struct request_queue *q)
{
- kobject_uevent(&e->kobj, KOBJ_REMOVE);
- kobject_del(&e->kobj);
- e->registered = 0;
+ return __elv_register_queue(q, q->elevator);
}
+EXPORT_SYMBOL(elv_register_queue);
void elv_unregister_queue(struct request_queue *q)
{
- if (q)
- __elv_unregister_queue(q->elevator);
+ if (q) {
+ struct elevator_queue *e = q->elevator;
+
+ kobject_uevent(&e->kobj, KOBJ_REMOVE);
+ kobject_del(&e->kobj);
+ e->registered = 0;
+ }
}
EXPORT_SYMBOL(elv_unregister_queue);
-void elv_register(struct elevator_type *e)
+int elv_register(struct elevator_type *e)
{
char *def = "";
+ /* create icq_cache if requested */
+ if (e->icq_size) {
+ if (WARN_ON(e->icq_size < sizeof(struct io_cq)) ||
+ WARN_ON(e->icq_align < __alignof__(struct io_cq)))
+ return -EINVAL;
+
+ snprintf(e->icq_cache_name, sizeof(e->icq_cache_name),
+ "%s_io_cq", e->elevator_name);
+ e->icq_cache = kmem_cache_create(e->icq_cache_name, e->icq_size,
+ e->icq_align, 0, NULL);
+ if (!e->icq_cache)
+ return -ENOMEM;
+ }
+
+ /* register, don't allow duplicate names */
spin_lock(&elv_list_lock);
- BUG_ON(elevator_find(e->elevator_name));
+ if (elevator_find(e->elevator_name)) {
+ spin_unlock(&elv_list_lock);
+ if (e->icq_cache)
+ kmem_cache_destroy(e->icq_cache);
+ return -EBUSY;
+ }
list_add_tail(&e->list, &elv_list);
spin_unlock(&elv_list_lock);
+ /* print pretty message */
if (!strcmp(e->elevator_name, chosen_elevator) ||
(!*chosen_elevator &&
!strcmp(e->elevator_name, CONFIG_DEFAULT_IOSCHED)))
printk(KERN_INFO "io scheduler %s registered%s\n", e->elevator_name,
def);
+ return 0;
}
EXPORT_SYMBOL_GPL(elv_register);
void elv_unregister(struct elevator_type *e)
{
- struct task_struct *g, *p;
+ /* unregister */
+ spin_lock(&elv_list_lock);
+ list_del_init(&e->list);
+ spin_unlock(&elv_list_lock);
/*
- * Iterate every thread in the process to remove the io contexts.
+ * Destroy icq_cache if it exists. icq's are RCU managed. Make
+ * sure all RCU operations are complete before proceeding.
*/
- if (e->ops.trim) {
- read_lock(&tasklist_lock);
- do_each_thread(g, p) {
- task_lock(p);
- if (p->io_context)
- e->ops.trim(p->io_context);
- task_unlock(p);
- } while_each_thread(g, p);
- read_unlock(&tasklist_lock);
+ if (e->icq_cache) {
+ rcu_barrier();
+ kmem_cache_destroy(e->icq_cache);
+ e->icq_cache = NULL;
}
-
- spin_lock(&elv_list_lock);
- list_del_init(&e->list);
- spin_unlock(&elv_list_lock);
}
EXPORT_SYMBOL_GPL(elv_unregister);
static int elevator_switch(struct request_queue *q, struct elevator_type *new_e)
{
struct elevator_queue *old_elevator, *e;
- void *data;
int err;
- /*
- * Allocate new elevator
- */
+ /* allocate new elevator */
e = elevator_alloc(q, new_e);
if (!e)
return -ENOMEM;
- data = elevator_init_queue(q, e);
- if (!data) {
+ err = elevator_init_queue(q, e);
+ if (err) {
kobject_put(&e->kobj);
- return -ENOMEM;
+ return err;
}
- /*
- * Turn on BYPASS and drain all requests w/ elevator private data
- */
+ /* turn on BYPASS and drain all requests w/ elevator private data */
elv_quiesce_start(q);
- /*
- * Remember old elevator.
- */
- old_elevator = q->elevator;
-
- /*
- * attach and start new elevator
- */
- spin_lock_irq(q->queue_lock);
- elevator_attach(q, e, data);
- spin_unlock_irq(q->queue_lock);
-
- if (old_elevator->registered) {
- __elv_unregister_queue(old_elevator);
-
- err = elv_register_queue(q);
+ /* unregister old queue, register new one and kill old elevator */
+ if (q->elevator->registered) {
+ elv_unregister_queue(q);
+ err = __elv_register_queue(q, e);
if (err)
goto fail_register;
}
- /*
- * finally exit old elevator and turn off BYPASS.
- */
+ /* done, clear io_cq's, switch elevators and turn off BYPASS */
+ spin_lock_irq(q->queue_lock);
+ ioc_clear_queue(q);
+ old_elevator = q->elevator;
+ q->elevator = e;
+ spin_unlock_irq(q->queue_lock);
+
elevator_exit(old_elevator);
elv_quiesce_end(q);
- blk_add_trace_msg(q, "elv switch: %s", e->elevator_type->elevator_name);
+ blk_add_trace_msg(q, "elv switch: %s", e->type->elevator_name);
return 0;
* one again (along with re-adding the sysfs dir)
*/
elevator_exit(e);
- q->elevator = old_elevator;
elv_register_queue(q);
elv_quiesce_end(q);
return -EINVAL;
}
- if (!strcmp(elevator_name, q->elevator->elevator_type->elevator_name)) {
+ if (!strcmp(elevator_name, q->elevator->type->elevator_name)) {
elevator_put(e);
return 0;
}
if (!q->elevator || !blk_queue_stackable(q))
return sprintf(name, "none\n");
- elv = e->elevator_type;
+ elv = e->type;
spin_lock(&elv_list_lock);
list_for_each_entry(__e, &elv_list, list) {
* Take an extra ref on queue which will be put on disk_release()
* so that it sticks around as long as @disk is there.
*/
- WARN_ON_ONCE(blk_get_queue(disk->queue));
+ WARN_ON_ONCE(!blk_get_queue(disk->queue));
retval = sysfs_create_link(&disk_to_dev(disk)->kobj, &bdi->dev->kobj,
"bdi");
return put_uint(arg, bdev_discard_zeroes_data(bdev));
case BLKSECTGET:
return put_ushort(arg, queue_max_sectors(bdev_get_queue(bdev)));
+ case BLKROTATIONAL:
+ return put_ushort(arg, !blk_queue_nonrot(bdev_get_queue(bdev)));
case BLKRASET:
case BLKFRASET:
if(!capable(CAP_SYS_ADMIN))
static int __init noop_init(void)
{
- elv_register(&elevator_noop);
-
- return 0;
+ return elv_register(&elevator_noop);
}
static void __exit noop_exit(void)
host->state == HST_DEV_SCAN);
spin_unlock_irq(&host->lock);
- DPRINTK("blk_insert_request, tag == %u\n", idx);
- blk_insert_request(host->oob_q, crq->rq, 1, crq);
+ DPRINTK("blk_execute_rq_nowait, tag == %u\n", idx);
+ crq->rq->cmd_type = REQ_TYPE_SPECIAL;
+ crq->rq->special = crq;
+ blk_execute_rq_nowait(host->oob_q, NULL, crq->rq, true, NULL);
return 0;
BUG_ON(rc < 0);
crq->msg_bucket = (u32) rc;
- DPRINTK("blk_insert_request, tag == %u\n", idx);
- blk_insert_request(host->oob_q, crq->rq, 1, crq);
+ DPRINTK("blk_execute_rq_nowait, tag == %u\n", idx);
+ crq->rq->cmd_type = REQ_TYPE_SPECIAL;
+ crq->rq->special = crq;
+ blk_execute_rq_nowait(host->oob_q, NULL, crq->rq, true, NULL);
return 0;
}
while (i < dm_table_get_num_targets(table)) {
ti = dm_table_get_target(table, i++);
- blk_set_default_limits(&ti_limits);
+ blk_set_stacking_limits(&ti_limits);
/* combine all target devices' limits */
if (ti->type->iterate_devices)
struct queue_limits ti_limits;
unsigned i = 0;
- blk_set_default_limits(limits);
+ blk_set_stacking_limits(limits);
while (i < dm_table_get_num_targets(table)) {
- blk_set_default_limits(&ti_limits);
+ blk_set_stacking_limits(&ti_limits);
ti = dm_table_get_target(table, i++);
mddev->queue->queuedata = mddev;
blk_queue_make_request(mddev->queue, md_make_request);
+ blk_set_stacking_limits(&mddev->queue->limits);
disk = alloc_disk(1 << shift);
if (!disk) {
kfree(sdev);
goto out;
}
- blk_get_queue(sdev->request_queue);
+ WARN_ON_ONCE(!blk_get_queue(sdev->request_queue));
sdev->request_queue->queuedata = sdev;
scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
if (err)
return err;
- task_lock(task);
- do {
- ioc = task->io_context;
- /* see wmb() in current_io_context() */
- smp_read_barrier_depends();
- if (ioc)
- break;
-
- ioc = alloc_io_context(GFP_ATOMIC, -1);
- if (!ioc) {
- err = -ENOMEM;
- break;
- }
- task->io_context = ioc;
- } while (1);
-
- if (!err) {
- ioc->ioprio = ioprio;
- ioc->ioprio_changed = 1;
+ ioc = get_task_io_context(task, GFP_ATOMIC, NUMA_NO_NODE);
+ if (ioc) {
+ ioc_ioprio_changed(ioc, ioprio);
+ put_io_context(ioc, NULL);
}
- task_unlock(task);
return err;
}
EXPORT_SYMBOL_GPL(set_task_ioprio);
sector_t last_block_in_bio = 0;
struct buffer_head map_bh;
unsigned long first_logical_block = 0;
- struct blk_plug plug;
-
- blk_start_plug(&plug);
map_bh.b_state = 0;
map_bh.b_size = 0;
BUG_ON(!list_empty(pages));
if (bio)
mpage_bio_submit(READ, bio);
- blk_finish_plug(&plug);
return 0;
}
EXPORT_SYMBOL(mpage_readpages);
#else /* CONFIG_BLK_DEV_INTEGRITY */
-#define bio_integrity(a) (0)
-#define bioset_integrity_create(a, b) (0)
-#define bio_integrity_prep(a) (0)
-#define bio_integrity_enabled(a) (0)
+static inline int bio_integrity(struct bio *bio)
+{
+ return 0;
+}
+
+static inline int bio_integrity_enabled(struct bio *bio)
+{
+ return 0;
+}
+
+static inline int bioset_integrity_create(struct bio_set *bs, int pool_size)
+{
+ return 0;
+}
+
+static inline void bioset_integrity_free (struct bio_set *bs)
+{
+ return;
+}
+
+static inline int bio_integrity_prep(struct bio *bio)
+{
+ return 0;
+}
+
+static inline void bio_integrity_free(struct bio *bio, struct bio_set *bs)
+{
+ return;
+}
+
static inline int bio_integrity_clone(struct bio *bio, struct bio *bio_src,
gfp_t gfp_mask, struct bio_set *bs)
{
return 0;
}
-#define bioset_integrity_free(a) do { } while (0)
-#define bio_integrity_free(a, b) do { } while (0)
-#define bio_integrity_endio(a, b) do { } while (0)
-#define bio_integrity_advance(a, b) do { } while (0)
-#define bio_integrity_trim(a, b, c) do { } while (0)
-#define bio_integrity_split(a, b, c) do { } while (0)
-#define bio_integrity_set_tag(a, b, c) do { } while (0)
-#define bio_integrity_get_tag(a, b, c) do { } while (0)
-#define bio_integrity_init(a) do { } while (0)
+
+static inline void bio_integrity_split(struct bio *bio, struct bio_pair *bp,
+ int sectors)
+{
+ return;
+}
+
+static inline void bio_integrity_advance(struct bio *bio,
+ unsigned int bytes_done)
+{
+ return;
+}
+
+static inline void bio_integrity_trim(struct bio *bio, unsigned int offset,
+ unsigned int sectors)
+{
+ return;
+}
+
+static inline void bio_integrity_init(void)
+{
+ return;
+}
#endif /* CONFIG_BLK_DEV_INTEGRITY */
* Three pointers are available for the IO schedulers, if they need
* more they have to dynamically allocate it. Flush requests are
* never put on the IO scheduler. So let the flush fields share
- * space with the three elevator_private pointers.
+ * space with the elevator data.
*/
union {
- void *elevator_private[3];
+ struct {
+ struct io_cq *icq;
+ void *priv[2];
+ } elv;
+
struct {
unsigned int seq;
struct list_head list;
*/
unsigned long queue_flags;
+ /*
+ * ida allocated id for this queue. Used to index queues from
+ * ioctx.
+ */
+ int id;
+
/*
* queue needs bounce pages for pages above this limit
*/
struct timer_list timeout;
struct list_head timeout_list;
+ struct list_head icq_list;
+
struct queue_limits limits;
/*
/* Throttle data */
struct throtl_data *td;
#endif
+#ifdef CONFIG_LOCKDEP
+ int ioc_release_depth;
+#endif
};
#define QUEUE_FLAG_QUEUED 1 /* uses generic tag queueing */
#define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
#define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
+#define blk_queue_dead(q) test_bit(QUEUE_FLAG_DEAD, &(q)->queue_flags)
#define blk_queue_nomerges(q) test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
#define blk_queue_noxmerges(q) \
test_bit(QUEUE_FLAG_NOXMERGES, &(q)->queue_flags)
extern struct request *blk_get_request(struct request_queue *, int, gfp_t);
extern struct request *blk_make_request(struct request_queue *, struct bio *,
gfp_t);
-extern void blk_insert_request(struct request_queue *, struct request *, int, void *);
extern void blk_requeue_request(struct request_queue *, struct request *);
extern void blk_add_request_payload(struct request *rq, struct page *page,
unsigned int len);
extern void blk_limits_io_opt(struct queue_limits *limits, unsigned int opt);
extern void blk_queue_io_opt(struct request_queue *q, unsigned int opt);
extern void blk_set_default_limits(struct queue_limits *lim);
+extern void blk_set_stacking_limits(struct queue_limits *lim);
extern int blk_stack_limits(struct queue_limits *t, struct queue_limits *b,
sector_t offset);
extern int bdev_stack_limits(struct queue_limits *t, struct block_device *bdev,
extern void blk_dump_rq_flags(struct request *, char *);
extern long nr_blockdev_pages(void);
-int blk_get_queue(struct request_queue *);
+bool __must_check blk_get_queue(struct request_queue *);
struct request_queue *blk_alloc_queue(gfp_t);
struct request_queue *blk_alloc_queue_node(gfp_t, int);
extern void blk_put_queue(struct request_queue *);
#else /* CONFIG_BLK_DEV_INTEGRITY */
-#define blk_integrity_rq(rq) (0)
-#define blk_rq_count_integrity_sg(a, b) (0)
-#define blk_rq_map_integrity_sg(a, b, c) (0)
-#define bdev_get_integrity(a) (0)
-#define blk_get_integrity(a) (0)
-#define blk_integrity_compare(a, b) (0)
-#define blk_integrity_register(a, b) (0)
-#define blk_integrity_unregister(a) do { } while (0)
-#define blk_queue_max_integrity_segments(a, b) do { } while (0)
-#define queue_max_integrity_segments(a) (0)
-#define blk_integrity_merge_rq(a, b, c) (0)
-#define blk_integrity_merge_bio(a, b, c) (0)
-#define blk_integrity_is_initialized(a) (0)
+struct bio;
+struct block_device;
+struct gendisk;
+struct blk_integrity;
+
+static inline int blk_integrity_rq(struct request *rq)
+{
+ return 0;
+}
+static inline int blk_rq_count_integrity_sg(struct request_queue *q,
+ struct bio *b)
+{
+ return 0;
+}
+static inline int blk_rq_map_integrity_sg(struct request_queue *q,
+ struct bio *b,
+ struct scatterlist *s)
+{
+ return 0;
+}
+static inline struct blk_integrity *bdev_get_integrity(struct block_device *b)
+{
+ return 0;
+}
+static inline struct blk_integrity *blk_get_integrity(struct gendisk *disk)
+{
+ return NULL;
+}
+static inline int blk_integrity_compare(struct gendisk *a, struct gendisk *b)
+{
+ return 0;
+}
+static inline int blk_integrity_register(struct gendisk *d,
+ struct blk_integrity *b)
+{
+ return 0;
+}
+static inline void blk_integrity_unregister(struct gendisk *d)
+{
+}
+static inline void blk_queue_max_integrity_segments(struct request_queue *q,
+ unsigned int segs)
+{
+}
+static inline unsigned short queue_max_integrity_segments(struct request_queue *q)
+{
+ return 0;
+}
+static inline int blk_integrity_merge_rq(struct request_queue *rq,
+ struct request *r1,
+ struct request *r2)
+{
+ return 0;
+}
+static inline int blk_integrity_merge_bio(struct request_queue *rq,
+ struct request *r,
+ struct bio *b)
+{
+ return 0;
+}
+static inline bool blk_integrity_is_initialized(struct gendisk *g)
+{
+ return 0;
+}
#endif /* CONFIG_BLK_DEV_INTEGRITY */
#ifdef CONFIG_BLOCK
+struct io_cq;
+
typedef int (elevator_merge_fn) (struct request_queue *, struct request **,
struct bio *);
typedef void (elevator_completed_req_fn) (struct request_queue *, struct request *);
typedef int (elevator_may_queue_fn) (struct request_queue *, int);
+typedef void (elevator_init_icq_fn) (struct io_cq *);
+typedef void (elevator_exit_icq_fn) (struct io_cq *);
typedef int (elevator_set_req_fn) (struct request_queue *, struct request *, gfp_t);
typedef void (elevator_put_req_fn) (struct request *);
typedef void (elevator_activate_req_fn) (struct request_queue *, struct request *);
elevator_request_list_fn *elevator_former_req_fn;
elevator_request_list_fn *elevator_latter_req_fn;
+ elevator_init_icq_fn *elevator_init_icq_fn; /* see iocontext.h */
+ elevator_exit_icq_fn *elevator_exit_icq_fn; /* ditto */
+
elevator_set_req_fn *elevator_set_req_fn;
elevator_put_req_fn *elevator_put_req_fn;
elevator_init_fn *elevator_init_fn;
elevator_exit_fn *elevator_exit_fn;
- void (*trim)(struct io_context *);
};
#define ELV_NAME_MAX (16)
*/
struct elevator_type
{
- struct list_head list;
+ /* managed by elevator core */
+ struct kmem_cache *icq_cache;
+
+ /* fields provided by elevator implementation */
struct elevator_ops ops;
+ size_t icq_size; /* see iocontext.h */
+ size_t icq_align; /* ditto */
struct elv_fs_entry *elevator_attrs;
char elevator_name[ELV_NAME_MAX];
struct module *elevator_owner;
+
+ /* managed by elevator core */
+ char icq_cache_name[ELV_NAME_MAX + 5]; /* elvname + "_io_cq" */
+ struct list_head list;
};
/*
*/
struct elevator_queue
{
- struct elevator_ops *ops;
+ struct elevator_type *type;
void *elevator_data;
struct kobject kobj;
- struct elevator_type *elevator_type;
struct mutex sysfs_lock;
struct hlist_head *hash;
unsigned int registered:1;
/*
* io scheduler registration
*/
-extern void elv_register(struct elevator_type *);
+extern int elv_register(struct elevator_type *);
extern void elv_unregister(struct elevator_type *);
/*
INIT_LIST_HEAD(&(rq)->csd.list); \
} while (0)
-/*
- * io context count accounting
- */
-#define elv_ioc_count_mod(name, __val) this_cpu_add(name, __val)
-#define elv_ioc_count_inc(name) this_cpu_inc(name)
-#define elv_ioc_count_dec(name) this_cpu_dec(name)
-
-#define elv_ioc_count_read(name) \
-({ \
- unsigned long __val = 0; \
- int __cpu; \
- smp_wmb(); \
- for_each_possible_cpu(__cpu) \
- __val += per_cpu(name, __cpu); \
- __val; \
-})
-
#endif /* CONFIG_BLOCK */
#endif
#define BLKPBSZGET _IO(0x12,123)
#define BLKDISCARDZEROES _IO(0x12,124)
#define BLKSECDISCARD _IO(0x12,125)
+#define BLKROTATIONAL _IO(0x12,126)
#define BMAP_IOCTL 1 /* obsolete - kept for compatibility */
#define FIBMAP _IO(0x00,1) /* bmap access */
#include <linux/radix-tree.h>
#include <linux/rcupdate.h>
+#include <linux/workqueue.h>
-struct cfq_queue;
-struct cfq_ttime {
- unsigned long last_end_request;
-
- unsigned long ttime_total;
- unsigned long ttime_samples;
- unsigned long ttime_mean;
+enum {
+ ICQ_IOPRIO_CHANGED,
+ ICQ_CGROUP_CHANGED,
};
-struct cfq_io_context {
- void *key;
-
- struct cfq_queue *cfqq[2];
-
- struct io_context *ioc;
-
- struct cfq_ttime ttime;
-
- struct list_head queue_list;
- struct hlist_node cic_list;
-
- void (*dtor)(struct io_context *); /* destructor */
- void (*exit)(struct io_context *); /* called on task exit */
+/*
+ * An io_cq (icq) is association between an io_context (ioc) and a
+ * request_queue (q). This is used by elevators which need to track
+ * information per ioc - q pair.
+ *
+ * Elevator can request use of icq by setting elevator_type->icq_size and
+ * ->icq_align. Both size and align must be larger than that of struct
+ * io_cq and elevator can use the tail area for private information. The
+ * recommended way to do this is defining a struct which contains io_cq as
+ * the first member followed by private members and using its size and
+ * align. For example,
+ *
+ * struct snail_io_cq {
+ * struct io_cq icq;
+ * int poke_snail;
+ * int feed_snail;
+ * };
+ *
+ * struct elevator_type snail_elv_type {
+ * .ops = { ... },
+ * .icq_size = sizeof(struct snail_io_cq),
+ * .icq_align = __alignof__(struct snail_io_cq),
+ * ...
+ * };
+ *
+ * If icq_size is set, block core will manage icq's. All requests will
+ * have its ->elv.icq field set before elevator_ops->elevator_set_req_fn()
+ * is called and be holding a reference to the associated io_context.
+ *
+ * Whenever a new icq is created, elevator_ops->elevator_init_icq_fn() is
+ * called and, on destruction, ->elevator_exit_icq_fn(). Both functions
+ * are called with both the associated io_context and queue locks held.
+ *
+ * Elevator is allowed to lookup icq using ioc_lookup_icq() while holding
+ * queue lock but the returned icq is valid only until the queue lock is
+ * released. Elevators can not and should not try to create or destroy
+ * icq's.
+ *
+ * As icq's are linked from both ioc and q, the locking rules are a bit
+ * complex.
+ *
+ * - ioc lock nests inside q lock.
+ *
+ * - ioc->icq_list and icq->ioc_node are protected by ioc lock.
+ * q->icq_list and icq->q_node by q lock.
+ *
+ * - ioc->icq_tree and ioc->icq_hint are protected by ioc lock, while icq
+ * itself is protected by q lock. However, both the indexes and icq
+ * itself are also RCU managed and lookup can be performed holding only
+ * the q lock.
+ *
+ * - icq's are not reference counted. They are destroyed when either the
+ * ioc or q goes away. Each request with icq set holds an extra
+ * reference to ioc to ensure it stays until the request is completed.
+ *
+ * - Linking and unlinking icq's are performed while holding both ioc and q
+ * locks. Due to the lock ordering, q exit is simple but ioc exit
+ * requires reverse-order double lock dance.
+ */
+struct io_cq {
+ struct request_queue *q;
+ struct io_context *ioc;
- struct rcu_head rcu_head;
+ /*
+ * q_node and ioc_node link io_cq through icq_list of q and ioc
+ * respectively. Both fields are unused once ioc_exit_icq() is
+ * called and shared with __rcu_icq_cache and __rcu_head which are
+ * used for RCU free of io_cq.
+ */
+ union {
+ struct list_head q_node;
+ struct kmem_cache *__rcu_icq_cache;
+ };
+ union {
+ struct hlist_node ioc_node;
+ struct rcu_head __rcu_head;
+ };
+
+ unsigned long changed;
};
/*
spinlock_t lock;
unsigned short ioprio;
- unsigned short ioprio_changed;
-
-#if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)
- unsigned short cgroup_changed;
-#endif
/*
* For request batching
int nr_batch_requests; /* Number of requests left in the batch */
unsigned long last_waited; /* Time last woken after wait for request */
- struct radix_tree_root radix_root;
- struct hlist_head cic_list;
- void __rcu *ioc_data;
+ struct radix_tree_root icq_tree;
+ struct io_cq __rcu *icq_hint;
+ struct hlist_head icq_list;
+
+ struct work_struct release_work;
};
static inline struct io_context *ioc_task_link(struct io_context *ioc)
struct task_struct;
#ifdef CONFIG_BLOCK
-int put_io_context(struct io_context *ioc);
+void put_io_context(struct io_context *ioc, struct request_queue *locked_q);
void exit_io_context(struct task_struct *task);
-struct io_context *get_io_context(gfp_t gfp_flags, int node);
-struct io_context *alloc_io_context(gfp_t gfp_flags, int node);
+struct io_context *get_task_io_context(struct task_struct *task,
+ gfp_t gfp_flags, int node);
+void ioc_ioprio_changed(struct io_context *ioc, int ioprio);
+void ioc_cgroup_changed(struct io_context *ioc);
#else
-static inline void exit_io_context(struct task_struct *task)
-{
-}
-
struct io_context;
-static inline int put_io_context(struct io_context *ioc)
-{
- return 1;
-}
+static inline void put_io_context(struct io_context *ioc,
+ struct request_queue *locked_q) { }
+static inline void exit_io_context(struct task_struct *task) { }
#endif
#endif
{
#ifdef CONFIG_BLOCK
struct io_context *ioc = current->io_context;
+ struct io_context *new_ioc;
if (!ioc)
return 0;
if (unlikely(!tsk->io_context))
return -ENOMEM;
} else if (ioprio_valid(ioc->ioprio)) {
- tsk->io_context = alloc_io_context(GFP_KERNEL, -1);
- if (unlikely(!tsk->io_context))
+ new_ioc = get_task_io_context(tsk, GFP_KERNEL, NUMA_NO_NODE);
+ if (unlikely(!new_ioc))
return -ENOMEM;
- tsk->io_context->ioprio = ioc->ioprio;
+ new_ioc->ioprio = ioc->ioprio;
+ put_io_context(new_ioc, NULL);
}
#endif
return 0;
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