From 03e04f048d2774aabd126fbad84729d4ba9dc40a Mon Sep 17 00:00:00 2001
From: Benjamin LaHaise <bcrl@kvack.org>
Date: Fri, 24 May 2013 15:55:38 -0700
Subject: [PATCH] aio: fix kioctx not being freed after cancellation at exit
time
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 | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/fs/aio.c b/fs/aio.c
index 3fcdd73b6f1b..7fe5bdee1630 100644
--- 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;
--
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