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Message-Id: <20100730173105.550947222@clark.site>
Date: Fri, 30 Jul 2010 10:29:56 -0700
From: Greg KH <gregkh@...e.de>
To: linux-kernel@...r.kernel.org, stable@...nel.org
Cc: stable-review@...nel.org, torvalds@...ux-foundation.org,
akpm@...ux-foundation.org, alan@...rguk.ukuu.org.uk,
Mikulas Patocka <mpatocka@...hat.com>,
"David S. Miller" <davem@...emloft.net>
Subject: [031/140] ide: Fix IDE taskfile with cfq scheduler
2.6.33-stable review patch. If anyone has any objections, please let us know.
------------------
From: Mikulas Patocka <mpatocka@...hat.com>
commit 720fc22a7af79d91ec460c80efa92c65c12d105e upstream.
When ide taskfile access is being used (for example with hdparm --security
commands) and cfq scheduler is selected, the scheduler crashes on BUG in
cfq_put_request.
The reason is that the cfq scheduler is tracking counts of read and write
requests separately; the ide-taskfile subsystem allocates a read request and
then flips the flag to make it a write request. The counters in cfq will
mismatch.
This patch changes ide-taskfile to allocate the READ or WRITE request as
required and don't change the flag later.
Signed-off-by: Mikulas Patocka <mpatocka@...hat.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@...e.de>
---
drivers/ide/ide-taskfile.c | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
--- a/drivers/ide/ide-taskfile.c
+++ b/drivers/ide/ide-taskfile.c
@@ -428,13 +428,11 @@ int ide_raw_taskfile(ide_drive_t *drive,
{
struct request *rq;
int error;
+ int rw = !(cmd->tf_flags & IDE_TFLAG_WRITE) ? READ : WRITE;
- rq = blk_get_request(drive->queue, READ, __GFP_WAIT);
+ rq = blk_get_request(drive->queue, rw, __GFP_WAIT);
rq->cmd_type = REQ_TYPE_ATA_TASKFILE;
- if (cmd->tf_flags & IDE_TFLAG_WRITE)
- rq->cmd_flags |= REQ_RW;
-
/*
* (ks) We transfer currently only whole sectors.
* This is suffient for now. But, it would be great,
--
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