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Merge git://git.kvack.org/~bcrl/aio-fixes 

Pull aio bugfixes from Ben LaHaise:
 "Two small fixes"

* git://git.kvack.org/~bcrl/aio-fixes:
  aio: block exit_aio() until all context requests are completed
  aio: add missing smp_rmb() in read_events_ring
This commit is contained in:
Linus Torvalds 2014-09-04 16:08:55 -07:00
parent 06ee709517 6098b45b32
commit b7fece1be8
1 changed files with 12 additions and 1 deletions
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13
fs/aio.c
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@ -793,6 +793,8 @@ void exit_aio(struct mm_struct *mm)
for (i = 0; i < table->nr; ++i) { for (i = 0; i < table->nr; ++i) {
struct kioctx *ctx = table->table[i]; struct kioctx *ctx = table->table[i];
struct completion requests_done =
COMPLETION_INITIALIZER_ONSTACK(requests_done);
if (!ctx) if (!ctx)
continue; continue;
@ -804,7 +806,10 @@ void exit_aio(struct mm_struct *mm)
* that it needs to unmap the area, just set it to 0. * that it needs to unmap the area, just set it to 0.
*/ */
ctx->mmap_size = 0; ctx->mmap_size = 0;
kill_ioctx(mm, ctx, NULL); kill_ioctx(mm, ctx, &requests_done);
/* Wait until all IO for the context are done. */
wait_for_completion(&requests_done);
} }
RCU_INIT_POINTER(mm->ioctx_table, NULL); RCU_INIT_POINTER(mm->ioctx_table, NULL);
@ -1111,6 +1116,12 @@ static long aio_read_events_ring(struct kioctx *ctx,
tail = ring->tail; tail = ring->tail;
kunmap_atomic(ring); kunmap_atomic(ring);
/*
* Ensure that once we've read the current tail pointer, that
* we also see the events that were stored up to the tail.
*/
smp_rmb();
pr_debug("h%u t%u m%u\n", head, tail, ctx->nr_events); pr_debug("h%u t%u m%u\n", head, tail, ctx->nr_events);
if (head == tail) if (head == tail)