| Date | Fri, 30 Jul 2010 10:29:56 -0700 | From | Greg KH <> | Subject | [031/140] ide: Fix IDE taskfile with cfq scheduler |
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2.6.33-stable review patch. If anyone has any objections, please let us know.
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From: Mikulas Patocka <mpatocka@redhat.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@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.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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