aio: fix kioctx not being freed after cancellation at exit time
authorBenjamin LaHaise <bcrl@kvack.org>
Fri, 24 May 2013 22:55:38 +0000 (15:55 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Fri, 24 May 2013 23:22:53 +0000 (16:22 -0700)
The recent changes overhauling fs/aio.c introduced a bug that results in
the kioctx not being freed when outstanding kiocbs are cancelled at
exit_aio() time.  Specifically, a kiocb that is cancelled has its
completion events discarded by batch_complete_aio(), which then fails to
wake up the process stuck in free_ioctx().  Fix this by modifying the
wait_event() condition in free_ioctx() appropriately.

This patch was tested with the cancel operation in the thread based code
posted yesterday.

[akpm@linux-foundation.org: fix build]
Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
Signed-off-by: Kent Overstreet <koverstreet@google.com>
Cc: Kent Overstreet <koverstreet@google.com>
Cc: Josh Boyer <jwboyer@redhat.com>
Cc: Zach Brown <zab@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/aio.c

index 3fcdd73..7fe5bde 100644 (file)
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -307,7 +307,9 @@ static void free_ioctx(struct kioctx *ctx)
        kunmap_atomic(ring);
 
        while (atomic_read(&ctx->reqs_active) > 0) {
-               wait_event(ctx->wait, head != ctx->tail);
+               wait_event(ctx->wait,
+                               head != ctx->tail ||
+                               atomic_read(&ctx->reqs_active) <= 0);
 
                avail = (head <= ctx->tail ? ctx->tail : ctx->nr_events) - head;