struct file *file;
off_t io_end;
- size_t io_pages;
+ size_t io_len;
};
struct io_ring_ctx {
#define REQ_F_IO_DRAIN 16 /* drain existing IO first */
#define REQ_F_IO_DRAINED 32 /* drain done */
#define REQ_F_LINK 64 /* linked sqes */
-#define REQ_F_FAIL_LINK 128 /* fail rest of links */
+#define REQ_F_LINK_DONE 128 /* linked sqes done */
+#define REQ_F_FAIL_LINK 256 /* fail rest of links */
u64 user_data;
u32 result;
u32 sequence;
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->sq_ring->dropped;
}
static struct io_kiocb *io_get_deferred_req(struct io_ring_ctx *ctx)
nxt->flags |= REQ_F_LINK;
}
+ nxt->flags |= REQ_F_LINK_DONE;
INIT_WORK(&nxt->work, io_sq_wq_submit_work);
queue_work(req->ctx->sqo_wq, &nxt->work);
}
io_free_req(req);
}
+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);
+}
+
/*
* 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->cq_ring))
+ 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;
}
*/
offset = buf_addr - imu->ubuf;
iov_iter_bvec(iter, rw, imu->bvec, imu->nr_bvecs, offset + len);
- if (offset)
- iov_iter_advance(iter, offset);
+
+ if (offset) {
+ /*
+ * Don't use iov_iter_advance() here, as it's really slow for
+ * using the latter parts of a big fixed buffer - it iterates
+ * over each segment manually. We can cheat a bit here, because
+ * we know that:
+ *
+ * 1) it's a BVEC iter, we set it up
+ * 2) all bvecs are PAGE_SIZE in size, except potentially the
+ * first and last bvec
+ *
+ * So just find our index, and adjust the iterator afterwards.
+ * If the offset is within the first bvec (or the whole first
+ * bvec, just use iov_iter_advance(). This makes it easier
+ * since we can just skip the first segment, which may not
+ * be PAGE_SIZE aligned.
+ */
+ const struct bio_vec *bvec = imu->bvec;
+
+ if (offset <= bvec->bv_len) {
+ iov_iter_advance(iter, offset);
+ } else {
+ unsigned long seg_skip;
+
+ /* skip first vec */
+ offset -= bvec->bv_len;
+ seg_skip = 1 + (offset >> PAGE_SHIFT);
+
+ iter->bvec = bvec + seg_skip;
+ iter->nr_segs -= seg_skip;
+ iter->count -= bvec->bv_len + offset;
+ iter->iov_offset = offset & ~PAGE_MASK;
+ }
+ }
+
return 0;
}
off_t io_end = kiocb->ki_pos + len;
if (filp == async_list->file && kiocb->ki_pos == async_list->io_end) {
- unsigned long max_pages;
+ unsigned long max_bytes;
/* Use 8x RA size as a decent limiter for both reads/writes */
- max_pages = filp->f_ra.ra_pages;
- if (!max_pages)
- max_pages = VM_READAHEAD_PAGES;
- max_pages *= 8;
-
- /* If max pages are exceeded, reset the state */
- len >>= PAGE_SHIFT;
- if (async_list->io_pages + len <= max_pages) {
+ max_bytes = filp->f_ra.ra_pages << (PAGE_SHIFT + 3);
+ if (!max_bytes)
+ max_bytes = VM_READAHEAD_PAGES << (PAGE_SHIFT + 3);
+
+ /* If max len are exceeded, reset the state */
+ if (async_list->io_len + len <= max_bytes) {
req->flags |= REQ_F_SEQ_PREV;
- async_list->io_pages += len;
+ async_list->io_len += len;
} else {
io_end = 0;
- async_list->io_pages = 0;
+ async_list->io_len = 0;
}
}
/* New file? Reset state. */
if (async_list->file != filp) {
- async_list->io_pages = 0;
+ async_list->io_len = 0;
async_list->file = filp;
}
async_list->io_end = io_end;
INIT_LIST_HEAD(&poll->wait.entry);
init_waitqueue_func_entry(&poll->wait, io_poll_wake);
+ INIT_LIST_HEAD(&req->list);
+
mask = vfs_poll(poll->file, &ipt.pt) & poll->events;
spin_lock_irq(&ctx->completion_lock);
do {
struct sqe_submit *s = &req->submit;
const struct io_uring_sqe *sqe = s->sqe;
+ unsigned int flags = req->flags;
/* Ensure we clear previously set non-block flag */
req->rw.ki_flags &= ~IOCB_NOWAIT;
/* async context always use a copy of the sqe */
kfree(sqe);
+ /* req from defer and link list needn't decrease async cnt */
+ if (flags & (REQ_F_IO_DRAINED | REQ_F_LINK_DONE))
+ goto out;
+
if (!async_list)
break;
if (!list_empty(&req_list)) {
}
}
+out:
if (cur_mm) {
set_fs(old_fs);
unuse_mm(cur_mm);
ret = true;
spin_lock(&list->lock);
list_add_tail(&req->list, &list->list);
+ /*
+ * Ensure we see a simultaneous modification from io_sq_wq_submit_work()
+ */
+ smp_mb();
if (!atomic_read(&list->cnt)) {
list_del_init(&req->list);
ret = false;
{
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;
+ }
+
ret = __io_submit_sqe(ctx, req, s, true);
if (ret == -EAGAIN && !(req->flags & REQ_F_NOWAIT)) {
struct io_uring_sqe *sqe_copy;
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
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.
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.
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);
}
projects / linux.git / blobdiff