Unused iocbs in a batch should not be accounted as active.
authorGleb Natapov <gleb@redhat.com>
Sun, 8 Jan 2012 15:07:28 +0000 (17:07 +0200)
committerLinus Torvalds <torvalds@linux-foundation.org>
Sat, 14 Jan 2012 04:39:44 +0000 (20:39 -0800)
commit69e4747ee9727d660b88d7e1efe0f4afcb35db1b
tree2dde4642ad0dba19688b664c4397c61cf9ebce25
parenta3301b751b19f0efbafddc4034f8e7ce6bf3007b
Unused iocbs in a batch should not be accounted as active.

Since commit 080d676de095 ("aio: allocate kiocbs in batches") iocbs are
allocated in a batch during processing of first iocbs.  All iocbs in a
batch are automatically added to ctx->active_reqs list and accounted in
ctx->reqs_active.

If one (not the last one) of iocbs submitted by an user fails, further
iocbs are not processed, but they are still present in ctx->active_reqs
and accounted in ctx->reqs_active.  This causes process to stuck in a D
state in wait_for_all_aios() on exit since ctx->reqs_active will never
go down to zero.  Furthermore since kiocb_batch_free() frees iocb
without removing it from active_reqs list the list become corrupted
which may cause oops.

Fix this by removing iocb from ctx->active_reqs and updating
ctx->reqs_active in kiocb_batch_free().

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Reviewed-by: Jeff Moyer <jmoyer@redhat.com>
Cc: stable@kernel.org # 3.2
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fs/aio.c