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ide-disk: Fix request requeuing

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commit 2c8fc86760 upstream.

Simon Kirby reported that on his RAID setup with idedisk underneath
the box OOMs after a couple of days of runtime. Running with
CONFIG_DEBUG_KMEMLEAK pointed to idedisk_prep_fn() which unconditionally
allocates an ide_cmd struct. However, ide_requeue_and_plug() can be
called more than once per request, either from the request issue or the
IRQ handler path and do blk_peek_request() ends up in idedisk_prep_fn()
repeatedly, allocating a struct ide_cmd everytime and "forgetting" the
previous pointer.

Make sure the code reuses the old allocated chunk.

Reported-and-tested-by: Simon Kirby <sim@hostway.ca>
Link: http://marc.info/?l=linux-kernel&m=131667641517919
Link: http://lkml.kernel.org/r/20110922072643.GA27232@hostway.ca
Signed-off-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Borislav Petkov 2011-10-03 14:28:18 -04:00 • committed by Greg Kroah-Hartman
commit 3217df8e22
1 changed files with 6 additions and 1 deletions
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7
drivers/ide/ide-disk.c
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@ -435,7 +435,12 @@ static int idedisk_prep_fn(struct request_queue *q, struct request *rq)
if (!(rq->cmd_flags & REQ_FLUSH))
return BLKPREP_OK;
cmd = kzalloc(sizeof(*cmd), GFP_ATOMIC);
if (rq->special) {
cmd = rq->special;
memset(cmd, 0, sizeof(*cmd));
} else {
cmd = kzalloc(sizeof(*cmd), GFP_ATOMIC);
}
/* FIXME: map struct ide_taskfile on rq->cmd[] */
BUG_ON(cmd == NULL);