#include "internal.h"
-#define IORING_MAX_ENTRIES 4096
+#define IORING_MAX_ENTRIES 32768
#define IORING_MAX_FIXED_FILES 1024
struct io_uring {
};
/*
- * This data is shared with the application through the mmap at offset
- * IORING_OFF_SQ_RING.
+ * This data is shared with the application through the mmap at offsets
+ * IORING_OFF_SQ_RING and IORING_OFF_CQ_RING.
*
* The offsets to the member fields are published through struct
* io_sqring_offsets when calling io_uring_setup.
*/
-struct io_sq_ring {
+struct io_rings {
/*
* Head and tail offsets into the ring; the offsets need to be
* masked to get valid indices.
*
- * The kernel controls head and the application controls tail.
+ * The kernel controls head of the sq ring and the tail of the cq ring,
+ * and the application controls tail of the sq ring and the head of the
+ * cq ring.
*/
- struct io_uring r;
+ struct io_uring sq, cq;
/*
- * Bitmask to apply to head and tail offsets (constant, equals
+ * Bitmasks to apply to head and tail offsets (constant, equals
* ring_entries - 1)
*/
- u32 ring_mask;
- /* Ring size (constant, power of 2) */
- u32 ring_entries;
+ u32 sq_ring_mask, cq_ring_mask;
+ /* Ring sizes (constant, power of 2) */
+ u32 sq_ring_entries, cq_ring_entries;
/*
* Number of invalid entries dropped by the kernel due to
* invalid index stored in array
* counter includes all submissions that were dropped reaching
* the new SQ head (and possibly more).
*/
- u32 dropped;
+ u32 sq_dropped;
/*
* Runtime flags
*
* The application needs a full memory barrier before checking
* for IORING_SQ_NEED_WAKEUP after updating the sq tail.
*/
- u32 flags;
- /*
- * Ring buffer of indices into array of io_uring_sqe, which is
- * mmapped by the application using the IORING_OFF_SQES offset.
- *
- * This indirection could e.g. be used to assign fixed
- * io_uring_sqe entries to operations and only submit them to
- * the queue when needed.
- *
- * The kernel modifies neither the indices array nor the entries
- * array.
- */
- u32 array[];
-};
-
-/*
- * This data is shared with the application through the mmap at offset
- * IORING_OFF_CQ_RING.
- *
- * The offsets to the member fields are published through struct
- * io_cqring_offsets when calling io_uring_setup.
- */
-struct io_cq_ring {
- /*
- * Head and tail offsets into the ring; the offsets need to be
- * masked to get valid indices.
- *
- * The application controls head and the kernel tail.
- */
- struct io_uring r;
- /*
- * Bitmask to apply to head and tail offsets (constant, equals
- * ring_entries - 1)
- */
- u32 ring_mask;
- /* Ring size (constant, power of 2) */
- u32 ring_entries;
+ u32 sq_flags;
/*
* Number of completion events lost because the queue was full;
* this should be avoided by the application by making sure
* As completion events come in out of order this counter is not
* ordered with any other data.
*/
- u32 overflow;
+ u32 cq_overflow;
/*
* Ring buffer of completion events.
*
* produced, so the application is allowed to modify pending
* entries.
*/
- struct io_uring_cqe cqes[];
+ struct io_uring_cqe cqes[] ____cacheline_aligned_in_smp;
};
struct io_mapped_ubuf {
struct list_head list;
struct file *file;
- off_t io_end;
+ off_t io_start;
size_t io_len;
};
bool compat;
bool account_mem;
- /* SQ ring */
- struct io_sq_ring *sq_ring;
+ /*
+ * Ring buffer of indices into array of io_uring_sqe, which is
+ * mmapped by the application using the IORING_OFF_SQES offset.
+ *
+ * This indirection could e.g. be used to assign fixed
+ * io_uring_sqe entries to operations and only submit them to
+ * the queue when needed.
+ *
+ * The kernel modifies neither the indices array nor the entries
+ * array.
+ */
+ u32 *sq_array;
unsigned cached_sq_head;
unsigned sq_entries;
unsigned sq_mask;
} ____cacheline_aligned_in_smp;
/* IO offload */
- struct workqueue_struct *sqo_wq;
+ struct workqueue_struct *sqo_wq[2];
struct task_struct *sqo_thread; /* if using sq thread polling */
struct mm_struct *sqo_mm;
wait_queue_head_t sqo_wait;
struct completion sqo_thread_started;
struct {
- /* CQ ring */
- struct io_cq_ring *cq_ring;
unsigned cached_cq_tail;
unsigned cq_entries;
unsigned cq_mask;
struct eventfd_ctx *cq_ev_fd;
} ____cacheline_aligned_in_smp;
+ struct io_rings *rings;
+
/*
* If used, fixed file set. Writers must ensure that ->refs is dead,
* readers must ensure that ->refs is alive as long as the file* is
struct sqe_submit {
const struct io_uring_sqe *sqe;
unsigned short index;
+ u32 sequence;
bool has_user;
bool needs_lock;
bool needs_fixed_file;
#define REQ_F_LINK 64 /* linked sqes */
#define REQ_F_LINK_DONE 128 /* linked sqes done */
#define REQ_F_FAIL_LINK 256 /* fail rest of links */
+#define REQ_F_SHADOW_DRAIN 512 /* link-drain shadow req */
u64 user_data;
u32 result;
u32 sequence;
};
static void io_sq_wq_submit_work(struct work_struct *work);
+static void __io_free_req(struct io_kiocb *req);
static struct kmem_cache *req_cachep;
if ((req->flags & (REQ_F_IO_DRAIN|REQ_F_IO_DRAINED)) != REQ_F_IO_DRAIN)
return false;
- return req->sequence != ctx->cached_cq_tail + ctx->sq_ring->dropped;
+ return req->sequence != ctx->cached_cq_tail + ctx->rings->sq_dropped;
}
static struct io_kiocb *io_get_deferred_req(struct io_ring_ctx *ctx)
static void __io_commit_cqring(struct io_ring_ctx *ctx)
{
- struct io_cq_ring *ring = ctx->cq_ring;
+ struct io_rings *rings = ctx->rings;
- if (ctx->cached_cq_tail != READ_ONCE(ring->r.tail)) {
+ if (ctx->cached_cq_tail != READ_ONCE(rings->cq.tail)) {
/* order cqe stores with ring update */
- smp_store_release(&ring->r.tail, ctx->cached_cq_tail);
+ smp_store_release(&rings->cq.tail, ctx->cached_cq_tail);
if (wq_has_sleeper(&ctx->cq_wait)) {
wake_up_interruptible(&ctx->cq_wait);
}
}
+static inline void io_queue_async_work(struct io_ring_ctx *ctx,
+ struct io_kiocb *req)
+{
+ int rw;
+
+ switch (req->submit.sqe->opcode) {
+ case IORING_OP_WRITEV:
+ case IORING_OP_WRITE_FIXED:
+ rw = !(req->rw.ki_flags & IOCB_DIRECT);
+ break;
+ default:
+ rw = 0;
+ break;
+ }
+
+ queue_work(ctx->sqo_wq[rw], &req->work);
+}
+
static void io_commit_cqring(struct io_ring_ctx *ctx)
{
struct io_kiocb *req;
__io_commit_cqring(ctx);
while ((req = io_get_deferred_req(ctx)) != NULL) {
+ if (req->flags & REQ_F_SHADOW_DRAIN) {
+ /* Just for drain, free it. */
+ __io_free_req(req);
+ continue;
+ }
req->flags |= REQ_F_IO_DRAINED;
- queue_work(ctx->sqo_wq, &req->work);
+ io_queue_async_work(ctx, req);
}
}
static struct io_uring_cqe *io_get_cqring(struct io_ring_ctx *ctx)
{
- struct io_cq_ring *ring = ctx->cq_ring;
+ struct io_rings *rings = ctx->rings;
unsigned tail;
tail = ctx->cached_cq_tail;
* control dependency is enough as we're using WRITE_ONCE to
* fill the cq entry
*/
- if (tail - READ_ONCE(ring->r.head) == ring->ring_entries)
+ if (tail - READ_ONCE(rings->cq.head) == rings->cq_ring_entries)
return NULL;
ctx->cached_cq_tail++;
- return &ring->cqes[tail & ctx->cq_mask];
+ return &rings->cqes[tail & ctx->cq_mask];
}
static void io_cqring_fill_event(struct io_ring_ctx *ctx, u64 ki_user_data,
WRITE_ONCE(cqe->res, res);
WRITE_ONCE(cqe->flags, 0);
} else {
- unsigned overflow = READ_ONCE(ctx->cq_ring->overflow);
+ unsigned overflow = READ_ONCE(ctx->rings->cq_overflow);
- WRITE_ONCE(ctx->cq_ring->overflow, overflow + 1);
+ WRITE_ONCE(ctx->rings->cq_overflow, overflow + 1);
}
}
nxt->flags |= REQ_F_LINK_DONE;
INIT_WORK(&nxt->work, io_sq_wq_submit_work);
- queue_work(req->ctx->sqo_wq, &nxt->work);
+ io_queue_async_work(req->ctx, nxt);
}
}
io_free_req(req);
}
+static unsigned io_cqring_events(struct io_rings *rings)
+{
+ /* See comment at the top of this file */
+ smp_rmb();
+ return READ_ONCE(rings->cq.tail) - READ_ONCE(rings->cq.head);
+}
+
/*
* Find and free completed poll iocbs
*/
static int io_iopoll_getevents(struct io_ring_ctx *ctx, unsigned int *nr_events,
long min)
{
- while (!list_empty(&ctx->poll_list)) {
+ while (!list_empty(&ctx->poll_list) && !need_resched()) {
int ret;
ret = io_do_iopoll(ctx, nr_events, min);
unsigned int nr_events = 0;
io_iopoll_getevents(ctx, &nr_events, 1);
+
+ /*
+ * Ensure we allow local-to-the-cpu processing to take place,
+ * in this case we need to ensure that we reap all events.
+ */
+ cond_resched();
}
mutex_unlock(&ctx->uring_lock);
}
static int io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events,
long min)
{
- int ret = 0;
+ int iters, ret = 0;
+ /*
+ * We disallow the app entering submit/complete with polling, but we
+ * still need to lock the ring to prevent racing with polled issue
+ * that got punted to a workqueue.
+ */
+ mutex_lock(&ctx->uring_lock);
+
+ iters = 0;
do {
int tmin = 0;
+ /*
+ * Don't enter poll loop if we already have events pending.
+ * If we do, we can potentially be spinning for commands that
+ * already triggered a CQE (eg in error).
+ */
+ if (io_cqring_events(ctx->rings))
+ break;
+
+ /*
+ * If a submit got punted to a workqueue, we can have the
+ * application entering polling for a command before it gets
+ * issued. That app will hold the uring_lock for the duration
+ * of the poll right here, so we need to take a breather every
+ * now and then to ensure that the issue has a chance to add
+ * the poll to the issued list. Otherwise we can spin here
+ * forever, while the workqueue is stuck trying to acquire the
+ * very same mutex.
+ */
+ if (!(++iters & 7)) {
+ mutex_unlock(&ctx->uring_lock);
+ mutex_lock(&ctx->uring_lock);
+ }
+
if (*nr_events < min)
tmin = min - *nr_events;
ret = 0;
} while (min && !*nr_events && !need_resched());
+ mutex_unlock(&ctx->uring_lock);
return ret;
}
iter->bvec = bvec + seg_skip;
iter->nr_segs -= seg_skip;
- iter->count -= (seg_skip << PAGE_SHIFT);
+ iter->count -= bvec->bv_len + offset;
iter->iov_offset = offset & ~PAGE_MASK;
- if (iter->iov_offset)
- iter->count -= iter->iov_offset;
}
}
return import_iovec(rw, buf, sqe_len, UIO_FASTIOV, iovec, iter);
}
+static inline bool io_should_merge(struct async_list *al, struct kiocb *kiocb)
+{
+ if (al->file == kiocb->ki_filp) {
+ off_t start, end;
+
+ /*
+ * Allow merging if we're anywhere in the range of the same
+ * page. Generally this happens for sub-page reads or writes,
+ * and it's beneficial to allow the first worker to bring the
+ * page in and the piggy backed work can then work on the
+ * cached page.
+ */
+ start = al->io_start & PAGE_MASK;
+ end = (al->io_start + al->io_len + PAGE_SIZE - 1) & PAGE_MASK;
+ if (kiocb->ki_pos >= start && kiocb->ki_pos <= end)
+ return true;
+ }
+
+ al->file = NULL;
+ return false;
+}
+
/*
* Make a note of the last file/offset/direction we punted to async
* context. We'll use this information to see if we can piggy back a
struct async_list *async_list = &req->ctx->pending_async[rw];
struct kiocb *kiocb = &req->rw;
struct file *filp = kiocb->ki_filp;
- off_t io_end = kiocb->ki_pos + len;
- if (filp == async_list->file && kiocb->ki_pos == async_list->io_end) {
+ if (io_should_merge(async_list, kiocb)) {
unsigned long max_bytes;
/* Use 8x RA size as a decent limiter for both reads/writes */
req->flags |= REQ_F_SEQ_PREV;
async_list->io_len += len;
} else {
- io_end = 0;
- async_list->io_len = 0;
+ async_list->file = NULL;
}
}
/* New file? Reset state. */
if (async_list->file != filp) {
- async_list->io_len = 0;
+ async_list->io_start = kiocb->ki_pos;
+ async_list->io_len = len;
async_list->file = filp;
}
- async_list->io_end = io_end;
}
static int io_read(struct io_kiocb *req, const struct sqe_submit *s,
WRITE_ONCE(poll->canceled, true);
if (!list_empty(&poll->wait.entry)) {
list_del_init(&poll->wait.entry);
- queue_work(req->ctx->sqo_wq, &req->work);
+ io_queue_async_work(req->ctx, req);
}
spin_unlock(&poll->head->lock);
io_cqring_ev_posted(ctx);
io_put_req(req);
} else {
- queue_work(ctx->sqo_wq, &req->work);
+ io_queue_async_work(ctx, req);
}
return 1;
*/
static bool io_add_to_prev_work(struct async_list *list, struct io_kiocb *req)
{
- bool ret = false;
+ bool ret;
if (!list)
return false;
flags = READ_ONCE(s->sqe->flags);
fd = READ_ONCE(s->sqe->fd);
- if (flags & IOSQE_IO_DRAIN) {
+ if (flags & IOSQE_IO_DRAIN)
req->flags |= REQ_F_IO_DRAIN;
- req->sequence = ctx->cached_sq_head - 1;
- }
+ /*
+ * All io need record the previous position, if LINK vs DARIN,
+ * it can be used to mark the position of the first IO in the
+ * link list.
+ */
+ req->sequence = s->sequence;
if (!io_op_needs_file(s->sqe))
return 0;
return 0;
}
-static int io_queue_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
- struct sqe_submit *s)
+static int __io_queue_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
+ struct sqe_submit *s, bool force_nonblock)
{
int ret;
- ret = __io_submit_sqe(ctx, req, s, true);
+ ret = __io_submit_sqe(ctx, req, s, force_nonblock);
if (ret == -EAGAIN && !(req->flags & REQ_F_NOWAIT)) {
struct io_uring_sqe *sqe_copy;
if (list)
atomic_inc(&list->cnt);
INIT_WORK(&req->work, io_sq_wq_submit_work);
- queue_work(ctx->sqo_wq, &req->work);
+ io_queue_async_work(ctx, req);
}
/*
return ret;
}
+static int io_queue_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
+ struct sqe_submit *s, bool force_nonblock)
+{
+ int ret;
+
+ ret = io_req_defer(ctx, req, s->sqe);
+ if (ret) {
+ if (ret != -EIOCBQUEUED) {
+ io_free_req(req);
+ io_cqring_add_event(ctx, s->sqe->user_data, ret);
+ }
+ return 0;
+ }
+
+ return __io_queue_sqe(ctx, req, s, force_nonblock);
+}
+
+static int io_queue_link_head(struct io_ring_ctx *ctx, struct io_kiocb *req,
+ struct sqe_submit *s, struct io_kiocb *shadow,
+ bool force_nonblock)
+{
+ int ret;
+ int need_submit = false;
+
+ if (!shadow)
+ return io_queue_sqe(ctx, req, s, force_nonblock);
+
+ /*
+ * Mark the first IO in link list as DRAIN, let all the following
+ * IOs enter the defer list. all IO needs to be completed before link
+ * list.
+ */
+ req->flags |= REQ_F_IO_DRAIN;
+ ret = io_req_defer(ctx, req, s->sqe);
+ if (ret) {
+ if (ret != -EIOCBQUEUED) {
+ io_free_req(req);
+ io_cqring_add_event(ctx, s->sqe->user_data, ret);
+ return 0;
+ }
+ } else {
+ /*
+ * If ret == 0 means that all IOs in front of link io are
+ * running done. let's queue link head.
+ */
+ need_submit = true;
+ }
+
+ /* Insert shadow req to defer_list, blocking next IOs */
+ spin_lock_irq(&ctx->completion_lock);
+ list_add_tail(&shadow->list, &ctx->defer_list);
+ spin_unlock_irq(&ctx->completion_lock);
+
+ if (need_submit)
+ return __io_queue_sqe(ctx, req, s, force_nonblock);
+
+ return 0;
+}
+
#define SQE_VALID_FLAGS (IOSQE_FIXED_FILE|IOSQE_IO_DRAIN|IOSQE_IO_LINK)
static void io_submit_sqe(struct io_ring_ctx *ctx, struct sqe_submit *s,
- struct io_submit_state *state, struct io_kiocb **link)
+ struct io_submit_state *state, struct io_kiocb **link,
+ bool force_nonblock)
{
struct io_uring_sqe *sqe_copy;
struct io_kiocb *req;
return;
}
- ret = io_req_defer(ctx, req, s->sqe);
- if (ret) {
- if (ret != -EIOCBQUEUED)
- goto err_req;
- return;
- }
-
/*
* If we already have a head request, queue this one for async
* submittal once the head completes. If we don't have a head but
INIT_LIST_HEAD(&req->link_list);
*link = req;
} else {
- io_queue_sqe(ctx, req, s);
+ io_queue_sqe(ctx, req, s, force_nonblock);
}
}
static void io_commit_sqring(struct io_ring_ctx *ctx)
{
- struct io_sq_ring *ring = ctx->sq_ring;
+ struct io_rings *rings = ctx->rings;
- if (ctx->cached_sq_head != READ_ONCE(ring->r.head)) {
+ if (ctx->cached_sq_head != READ_ONCE(rings->sq.head)) {
/*
* Ensure any loads from the SQEs are done at this point,
* since once we write the new head, the application could
* write new data to them.
*/
- smp_store_release(&ring->r.head, ctx->cached_sq_head);
+ smp_store_release(&rings->sq.head, ctx->cached_sq_head);
}
}
*/
static bool io_get_sqring(struct io_ring_ctx *ctx, struct sqe_submit *s)
{
- struct io_sq_ring *ring = ctx->sq_ring;
+ struct io_rings *rings = ctx->rings;
+ u32 *sq_array = ctx->sq_array;
unsigned head;
/*
*/
head = ctx->cached_sq_head;
/* make sure SQ entry isn't read before tail */
- if (head == smp_load_acquire(&ring->r.tail))
+ if (head == smp_load_acquire(&rings->sq.tail))
return false;
- head = READ_ONCE(ring->array[head & ctx->sq_mask]);
+ head = READ_ONCE(sq_array[head & ctx->sq_mask]);
if (head < ctx->sq_entries) {
s->index = head;
s->sqe = &ctx->sq_sqes[head];
+ s->sequence = ctx->cached_sq_head;
ctx->cached_sq_head++;
return true;
}
/* drop invalid entries */
ctx->cached_sq_head++;
- ring->dropped++;
+ rings->sq_dropped++;
return false;
}
{
struct io_submit_state state, *statep = NULL;
struct io_kiocb *link = NULL;
+ struct io_kiocb *shadow_req = NULL;
bool prev_was_link = false;
int i, submitted = 0;
* that's the end of the chain. Submit the previous link.
*/
if (!prev_was_link && link) {
- io_queue_sqe(ctx, link, &link->submit);
+ io_queue_link_head(ctx, link, &link->submit, shadow_req,
+ true);
link = NULL;
}
prev_was_link = (sqes[i].sqe->flags & IOSQE_IO_LINK) != 0;
+ if (link && (sqes[i].sqe->flags & IOSQE_IO_DRAIN)) {
+ if (!shadow_req) {
+ shadow_req = io_get_req(ctx, NULL);
+ shadow_req->flags |= (REQ_F_IO_DRAIN | REQ_F_SHADOW_DRAIN);
+ refcount_dec(&shadow_req->refs);
+ }
+ shadow_req->sequence = sqes[i].sequence;
+ }
+
if (unlikely(mm_fault)) {
io_cqring_add_event(ctx, sqes[i].sqe->user_data,
-EFAULT);
sqes[i].has_user = has_user;
sqes[i].needs_lock = true;
sqes[i].needs_fixed_file = true;
- io_submit_sqe(ctx, &sqes[i], statep, &link);
+ io_submit_sqe(ctx, &sqes[i], statep, &link, true);
submitted++;
}
}
if (link)
- io_queue_sqe(ctx, link, &link->submit);
+ io_queue_link_head(ctx, link, &link->submit, shadow_req, true);
if (statep)
io_submit_state_end(&state);
unsigned nr_events = 0;
if (ctx->flags & IORING_SETUP_IOPOLL) {
- /*
- * We disallow the app entering submit/complete
- * with polling, but we still need to lock the
- * ring to prevent racing with polled issue
- * that got punted to a workqueue.
- */
- mutex_lock(&ctx->uring_lock);
io_iopoll_check(ctx, &nr_events, 0);
- mutex_unlock(&ctx->uring_lock);
} else {
/*
* Normal IO, just pretend everything completed.
TASK_INTERRUPTIBLE);
/* Tell userspace we may need a wakeup call */
- ctx->sq_ring->flags |= IORING_SQ_NEED_WAKEUP;
+ ctx->rings->sq_flags |= IORING_SQ_NEED_WAKEUP;
/* make sure to read SQ tail after writing flags */
smp_mb();
schedule();
finish_wait(&ctx->sqo_wait, &wait);
- ctx->sq_ring->flags &= ~IORING_SQ_NEED_WAKEUP;
+ ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP;
continue;
}
finish_wait(&ctx->sqo_wait, &wait);
- ctx->sq_ring->flags &= ~IORING_SQ_NEED_WAKEUP;
+ ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP;
}
i = 0;
return 0;
}
-static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit)
+static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit,
+ bool block_for_last)
{
struct io_submit_state state, *statep = NULL;
struct io_kiocb *link = NULL;
+ struct io_kiocb *shadow_req = NULL;
bool prev_was_link = false;
int i, submit = 0;
}
for (i = 0; i < to_submit; i++) {
+ bool force_nonblock = true;
struct sqe_submit s;
if (!io_get_sqring(ctx, &s))
* that's the end of the chain. Submit the previous link.
*/
if (!prev_was_link && link) {
- io_queue_sqe(ctx, link, &link->submit);
+ io_queue_link_head(ctx, link, &link->submit, shadow_req,
+ force_nonblock);
link = NULL;
}
prev_was_link = (s.sqe->flags & IOSQE_IO_LINK) != 0;
+ if (link && (s.sqe->flags & IOSQE_IO_DRAIN)) {
+ if (!shadow_req) {
+ shadow_req = io_get_req(ctx, NULL);
+ shadow_req->flags |= (REQ_F_IO_DRAIN | REQ_F_SHADOW_DRAIN);
+ refcount_dec(&shadow_req->refs);
+ }
+ shadow_req->sequence = s.sequence;
+ }
+
s.has_user = true;
s.needs_lock = false;
s.needs_fixed_file = false;
submit++;
- io_submit_sqe(ctx, &s, statep, &link);
+
+ /*
+ * The caller will block for events after submit, submit the
+ * last IO non-blocking. This is either the only IO it's
+ * submitting, or it already submitted the previous ones. This
+ * improves performance by avoiding an async punt that we don't
+ * need to do.
+ */
+ if (block_for_last && submit == to_submit)
+ force_nonblock = false;
+
+ io_submit_sqe(ctx, &s, statep, &link, force_nonblock);
}
io_commit_sqring(ctx);
if (link)
- io_queue_sqe(ctx, link, &link->submit);
+ io_queue_link_head(ctx, link, &link->submit, shadow_req,
+ block_for_last);
if (statep)
io_submit_state_end(statep);
return submit;
}
-static unsigned io_cqring_events(struct io_cq_ring *ring)
-{
- /* See comment at the top of this file */
- smp_rmb();
- return READ_ONCE(ring->r.tail) - READ_ONCE(ring->r.head);
-}
-
/*
* Wait until events become available, if we don't already have some. The
* application must reap them itself, as they reside on the shared cq ring.
static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
const sigset_t __user *sig, size_t sigsz)
{
- struct io_cq_ring *ring = ctx->cq_ring;
+ struct io_rings *rings = ctx->rings;
int ret;
- if (io_cqring_events(ring) >= min_events)
+ if (io_cqring_events(rings) >= min_events)
return 0;
if (sig) {
return ret;
}
- ret = wait_event_interruptible(ctx->wait, io_cqring_events(ring) >= min_events);
+ ret = wait_event_interruptible(ctx->wait, io_cqring_events(rings) >= min_events);
restore_saved_sigmask_unless(ret == -ERESTARTSYS);
if (ret == -ERESTARTSYS)
ret = -EINTR;
- return READ_ONCE(ring->r.head) == READ_ONCE(ring->r.tail) ? ret : 0;
+ return READ_ONCE(rings->cq.head) == READ_ONCE(rings->cq.tail) ? ret : 0;
}
static void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
static void io_finish_async(struct io_ring_ctx *ctx)
{
+ int i;
+
io_sq_thread_stop(ctx);
- if (ctx->sqo_wq) {
- destroy_workqueue(ctx->sqo_wq);
- ctx->sqo_wq = NULL;
+ for (i = 0; i < ARRAY_SIZE(ctx->sqo_wq); i++) {
+ if (ctx->sqo_wq[i]) {
+ destroy_workqueue(ctx->sqo_wq[i]);
+ ctx->sqo_wq[i] = NULL;
+ }
}
}
}
/* Do QD, or 2 * CPUS, whatever is smallest */
- ctx->sqo_wq = alloc_workqueue("io_ring-wq", WQ_UNBOUND | WQ_FREEZABLE,
+ ctx->sqo_wq[0] = alloc_workqueue("io_ring-wq",
+ WQ_UNBOUND | WQ_FREEZABLE,
min(ctx->sq_entries - 1, 2 * num_online_cpus()));
- if (!ctx->sqo_wq) {
+ if (!ctx->sqo_wq[0]) {
+ ret = -ENOMEM;
+ goto err;
+ }
+
+ /*
+ * This is for buffered writes, where we want to limit the parallelism
+ * due to file locking in file systems. As "normal" buffered writes
+ * should parellelize on writeout quite nicely, limit us to having 2
+ * pending. This avoids massive contention on the inode when doing
+ * buffered async writes.
+ */
+ ctx->sqo_wq[1] = alloc_workqueue("io_ring-write-wq",
+ WQ_UNBOUND | WQ_FREEZABLE, 2);
+ if (!ctx->sqo_wq[1]) {
ret = -ENOMEM;
goto err;
}
return 0;
err:
- io_sq_thread_stop(ctx);
+ io_finish_async(ctx);
mmdrop(ctx->sqo_mm);
ctx->sqo_mm = NULL;
return ret;
return (void *) __get_free_pages(gfp_flags, get_order(size));
}
+static unsigned long rings_size(unsigned sq_entries, unsigned cq_entries,
+ size_t *sq_offset)
+{
+ struct io_rings *rings;
+ size_t off, sq_array_size;
+
+ off = struct_size(rings, cqes, cq_entries);
+ if (off == SIZE_MAX)
+ return SIZE_MAX;
+
+#ifdef CONFIG_SMP
+ off = ALIGN(off, SMP_CACHE_BYTES);
+ if (off == 0)
+ return SIZE_MAX;
+#endif
+
+ sq_array_size = array_size(sizeof(u32), sq_entries);
+ if (sq_array_size == SIZE_MAX)
+ return SIZE_MAX;
+
+ if (check_add_overflow(off, sq_array_size, &off))
+ return SIZE_MAX;
+
+ if (sq_offset)
+ *sq_offset = off;
+
+ return off;
+}
+
static unsigned long ring_pages(unsigned sq_entries, unsigned cq_entries)
{
- struct io_sq_ring *sq_ring;
- struct io_cq_ring *cq_ring;
- size_t bytes;
+ size_t pages;
- bytes = struct_size(sq_ring, array, sq_entries);
- bytes += array_size(sizeof(struct io_uring_sqe), sq_entries);
- bytes += struct_size(cq_ring, cqes, cq_entries);
+ pages = (size_t)1 << get_order(
+ rings_size(sq_entries, cq_entries, NULL));
+ pages += (size_t)1 << get_order(
+ array_size(sizeof(struct io_uring_sqe), sq_entries));
- return (bytes + PAGE_SIZE - 1) / PAGE_SIZE;
+ return pages;
}
static int io_sqe_buffer_unregister(struct io_ring_ctx *ctx)
struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
for (j = 0; j < imu->nr_bvecs; j++)
- put_page(imu->bvec[j].bv_page);
+ put_user_page(imu->bvec[j].bv_page);
if (ctx->account_mem)
io_unaccount_mem(ctx->user, imu->nr_bvecs);
* if we did partial map, or found file backed vmas,
* release any pages we did get
*/
- if (pret > 0) {
- for (j = 0; j < pret; j++)
- put_page(pages[j]);
- }
+ if (pret > 0)
+ put_user_pages(pages, pret);
if (ctx->account_mem)
io_unaccount_mem(ctx->user, nr_pages);
kvfree(imu->bvec);
}
#endif
- io_mem_free(ctx->sq_ring);
+ io_mem_free(ctx->rings);
io_mem_free(ctx->sq_sqes);
- io_mem_free(ctx->cq_ring);
percpu_ref_exit(&ctx->refs);
if (ctx->account_mem)
* io_commit_cqring
*/
smp_rmb();
- if (READ_ONCE(ctx->sq_ring->r.tail) - ctx->cached_sq_head !=
- ctx->sq_ring->ring_entries)
+ if (READ_ONCE(ctx->rings->sq.tail) - ctx->cached_sq_head !=
+ ctx->rings->sq_ring_entries)
mask |= EPOLLOUT | EPOLLWRNORM;
- if (READ_ONCE(ctx->cq_ring->r.head) != ctx->cached_cq_tail)
+ if (READ_ONCE(ctx->rings->sq.head) != ctx->cached_cq_tail)
mask |= EPOLLIN | EPOLLRDNORM;
return mask;
switch (offset) {
case IORING_OFF_SQ_RING:
- ptr = ctx->sq_ring;
+ case IORING_OFF_CQ_RING:
+ ptr = ctx->rings;
break;
case IORING_OFF_SQES:
ptr = ctx->sq_sqes;
break;
- case IORING_OFF_CQ_RING:
- ptr = ctx->cq_ring;
- break;
default:
return -EINVAL;
}
* Just return the requested submit count, and wake the thread if
* we were asked to.
*/
+ ret = 0;
if (ctx->flags & IORING_SETUP_SQPOLL) {
if (flags & IORING_ENTER_SQ_WAKEUP)
wake_up(&ctx->sqo_wait);
submitted = to_submit;
- goto out_ctx;
- }
+ } else if (to_submit) {
+ bool block_for_last = false;
- ret = 0;
- if (to_submit) {
to_submit = min(to_submit, ctx->sq_entries);
+ /*
+ * Allow last submission to block in a series, IFF the caller
+ * asked to wait for events and we don't currently have
+ * enough. This potentially avoids an async punt.
+ */
+ if (to_submit == min_complete &&
+ io_cqring_events(ctx->rings) < min_complete)
+ block_for_last = true;
+
mutex_lock(&ctx->uring_lock);
- submitted = io_ring_submit(ctx, to_submit);
+ submitted = io_ring_submit(ctx, to_submit, block_for_last);
mutex_unlock(&ctx->uring_lock);
}
if (flags & IORING_ENTER_GETEVENTS) {
min_complete = min(min_complete, ctx->cq_entries);
if (ctx->flags & IORING_SETUP_IOPOLL) {
- mutex_lock(&ctx->uring_lock);
ret = io_iopoll_check(ctx, &nr_events, min_complete);
- mutex_unlock(&ctx->uring_lock);
} else {
ret = io_cqring_wait(ctx, min_complete, sig, sigsz);
}
}
-out_ctx:
io_ring_drop_ctx_refs(ctx, 1);
out_fput:
fdput(f);
static int io_allocate_scq_urings(struct io_ring_ctx *ctx,
struct io_uring_params *p)
{
- struct io_sq_ring *sq_ring;
- struct io_cq_ring *cq_ring;
- size_t size;
+ struct io_rings *rings;
+ size_t size, sq_array_offset;
- sq_ring = io_mem_alloc(struct_size(sq_ring, array, p->sq_entries));
- if (!sq_ring)
+ size = rings_size(p->sq_entries, p->cq_entries, &sq_array_offset);
+ if (size == SIZE_MAX)
+ return -EOVERFLOW;
+
+ rings = io_mem_alloc(size);
+ if (!rings)
return -ENOMEM;
- ctx->sq_ring = sq_ring;
- sq_ring->ring_mask = p->sq_entries - 1;
- sq_ring->ring_entries = p->sq_entries;
- ctx->sq_mask = sq_ring->ring_mask;
- ctx->sq_entries = sq_ring->ring_entries;
+ ctx->rings = rings;
+ ctx->sq_array = (u32 *)((char *)rings + sq_array_offset);
+ rings->sq_ring_mask = p->sq_entries - 1;
+ rings->cq_ring_mask = p->cq_entries - 1;
+ rings->sq_ring_entries = p->sq_entries;
+ rings->cq_ring_entries = p->cq_entries;
+ ctx->sq_mask = rings->sq_ring_mask;
+ ctx->cq_mask = rings->cq_ring_mask;
+ ctx->sq_entries = rings->sq_ring_entries;
+ ctx->cq_entries = rings->cq_ring_entries;
size = array_size(sizeof(struct io_uring_sqe), p->sq_entries);
if (size == SIZE_MAX)
if (!ctx->sq_sqes)
return -ENOMEM;
- cq_ring = io_mem_alloc(struct_size(cq_ring, cqes, p->cq_entries));
- if (!cq_ring)
- return -ENOMEM;
-
- ctx->cq_ring = cq_ring;
- cq_ring->ring_mask = p->cq_entries - 1;
- cq_ring->ring_entries = p->cq_entries;
- ctx->cq_mask = cq_ring->ring_mask;
- ctx->cq_entries = cq_ring->ring_entries;
return 0;
}
goto err;
memset(&p->sq_off, 0, sizeof(p->sq_off));
- p->sq_off.head = offsetof(struct io_sq_ring, r.head);
- p->sq_off.tail = offsetof(struct io_sq_ring, r.tail);
- p->sq_off.ring_mask = offsetof(struct io_sq_ring, ring_mask);
- p->sq_off.ring_entries = offsetof(struct io_sq_ring, ring_entries);
- p->sq_off.flags = offsetof(struct io_sq_ring, flags);
- p->sq_off.dropped = offsetof(struct io_sq_ring, dropped);
- p->sq_off.array = offsetof(struct io_sq_ring, array);
+ p->sq_off.head = offsetof(struct io_rings, sq.head);
+ p->sq_off.tail = offsetof(struct io_rings, sq.tail);
+ p->sq_off.ring_mask = offsetof(struct io_rings, sq_ring_mask);
+ p->sq_off.ring_entries = offsetof(struct io_rings, sq_ring_entries);
+ p->sq_off.flags = offsetof(struct io_rings, sq_flags);
+ p->sq_off.dropped = offsetof(struct io_rings, sq_dropped);
+ p->sq_off.array = (char *)ctx->sq_array - (char *)ctx->rings;
memset(&p->cq_off, 0, sizeof(p->cq_off));
- p->cq_off.head = offsetof(struct io_cq_ring, r.head);
- p->cq_off.tail = offsetof(struct io_cq_ring, r.tail);
- p->cq_off.ring_mask = offsetof(struct io_cq_ring, ring_mask);
- p->cq_off.ring_entries = offsetof(struct io_cq_ring, ring_entries);
- p->cq_off.overflow = offsetof(struct io_cq_ring, overflow);
- p->cq_off.cqes = offsetof(struct io_cq_ring, cqes);
+ p->cq_off.head = offsetof(struct io_rings, cq.head);
+ p->cq_off.tail = offsetof(struct io_rings, cq.tail);
+ p->cq_off.ring_mask = offsetof(struct io_rings, cq_ring_mask);
+ p->cq_off.ring_entries = offsetof(struct io_rings, cq_ring_entries);
+ p->cq_off.overflow = offsetof(struct io_rings, cq_overflow);
+ p->cq_off.cqes = offsetof(struct io_rings, cqes);
+
+ p->features = IORING_FEAT_SINGLE_MMAP;
return ret;
err:
io_ring_ctx_wait_and_kill(ctx);
projects / linux.git / blobdiff