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-rw-r--r--fs/aio.c42
1 files changed, 23 insertions, 19 deletions
diff --git a/fs/aio.c b/fs/aio.c
index 12b37689dd2c..57b02791d04e 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -406,7 +406,8 @@ static void free_ioctx(struct work_struct *work)
struct kioctx *ctx = container_of(work, struct kioctx, free_work);
struct aio_ring *ring;
struct kiocb *req;
- unsigned cpu, head, avail;
+ unsigned cpu, avail;
+ DEFINE_WAIT(wait);
spin_lock_irq(&ctx->ctx_lock);
@@ -427,22 +428,24 @@ static void free_ioctx(struct work_struct *work)
kcpu->reqs_available = 0;
}
- ring = kmap_atomic(ctx->ring_pages[0]);
- head = ring->head;
- kunmap_atomic(ring);
+ while (1) {
+ prepare_to_wait(&ctx->wait, &wait, TASK_UNINTERRUPTIBLE);
- while (atomic_read(&ctx->reqs_available) < ctx->nr_events - 1) {
- wait_event(ctx->wait,
- (head != ctx->tail) ||
- (atomic_read(&ctx->reqs_available) >=
- ctx->nr_events - 1));
-
- avail = (head <= ctx->tail ? ctx->tail : ctx->nr_events) - head;
+ ring = kmap_atomic(ctx->ring_pages[0]);
+ avail = (ring->head <= ring->tail)
+ ? ring->tail - ring->head
+ : ctx->nr_events - ring->head + ring->tail;
atomic_add(avail, &ctx->reqs_available);
- head += avail;
- head %= ctx->nr_events;
+ ring->head = ring->tail;
+ kunmap_atomic(ring);
+
+ if (atomic_read(&ctx->reqs_available) >= ctx->nr_events - 1)
+ break;
+
+ schedule();
}
+ finish_wait(&ctx->wait, &wait);
WARN_ON(atomic_read(&ctx->reqs_available) > ctx->nr_events - 1);
@@ -869,7 +872,7 @@ static long aio_read_events_ring(struct kioctx *ctx,
struct io_event __user *event, long nr)
{
struct aio_ring *ring;
- unsigned head, pos;
+ unsigned head, tail, pos;
long ret = 0;
int copy_ret;
@@ -877,11 +880,12 @@ static long aio_read_events_ring(struct kioctx *ctx,
ring = kmap_atomic(ctx->ring_pages[0]);
head = ring->head;
+ tail = ring->tail;
kunmap_atomic(ring);
- pr_debug("h%u t%u m%u\n", head, ctx->tail, ctx->nr_events);
+ pr_debug("h%u t%u m%u\n", head, tail, ctx->nr_events);
- if (head == ctx->tail)
+ if (head == tail)
goto out;
while (ret < nr) {
@@ -889,8 +893,8 @@ static long aio_read_events_ring(struct kioctx *ctx,
struct io_event *ev;
struct page *page;
- avail = (head <= ctx->tail ? ctx->tail : ctx->nr_events) - head;
- if (head == ctx->tail)
+ avail = (head <= tail ? tail : ctx->nr_events) - head;
+ if (head == tail)
break;
avail = min(avail, nr - ret);
@@ -921,7 +925,7 @@ static long aio_read_events_ring(struct kioctx *ctx,
kunmap_atomic(ring);
flush_dcache_page(ctx->ring_pages[0]);
- pr_debug("%li h%u t%u\n", ret, head, ctx->tail);
+ pr_debug("%li h%u t%u\n", ret, head, tail);
put_reqs_available(ctx, ret);
out: