The patch titled
Subject: aio: fix kioctx not being freed after cancellation at exit time
has been removed from the -mm tree. Its filename was
aio-v2-fix-kioctx-not-being-freed-after-cancellation-at-exit-time.patch
This patch was dropped because an updated version will be merged
------------------------------------------------------
From: Benjamin LaHaise <bcrl@xxxxxxxxx>
Subject: 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 removing the event suppression in
batch_complete_aio() and modify the wait_event() condition in free_ioctx()
appropriately.
This patch was tested with the cancel operation in the thread based code
posted yesterday.
Signed-off-by: Benjamin LaHaise <bcrl@xxxxxxxxx>
Cc: Kent Overstreet <koverstreet@xxxxxxxxxx>
Cc: Josh Boyer <jwboyer@xxxxxxxxxx>
Cc: Zach Brown <zab@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/aio.c | 15 +++------------
1 file changed, 3 insertions(+), 12 deletions(-)
diff -puN fs/aio.c~aio-v2-fix-kioctx-not-being-freed-after-cancellation-at-exit-time fs/aio.c
--- a/fs/aio.c~aio-v2-fix-kioctx-not-being-freed-after-cancellation-at-exit-time
+++ a/fs/aio.c
@@ -335,7 +335,9 @@ static void free_ioctx(struct kioctx *ct
kunmap_atomic(ring);
while (atomic_read(&ctx->reqs_available) < ctx->nr) {
- wait_event(ctx->wait, head != ctx->shadow_tail);
+ wait_event(ctx->wait,
+ (head != ctx->shadow_tail) ||
+ (atomic_read(&ctx->reqs_available) >= ctx->nr));
avail = (head <= ctx->shadow_tail ?
ctx->shadow_tail : ctx->nr) - head;
@@ -748,17 +750,6 @@ void batch_complete_aio(struct batch_com
n = rb_parent(n);
}
- if (unlikely(xchg(&req->ki_cancel,
- KIOCB_CANCELLED) == KIOCB_CANCELLED)) {
- /*
- * Can't use the percpu reqs_available here - could race
- * with free_ioctx()
- */
- atomic_inc(&req->ki_ctx->reqs_available);
- aio_put_req(req);
- continue;
- }
-
if (unlikely(req->ki_eventfd != eventfd)) {
if (eventfd) {
/* Make event visible */
_
Patches currently in -mm which might be from bcrl@xxxxxxxxx are
aio-fix-ringbuffer-calculation-so-we-dont-wrap.patch
--
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
