[031/140] ide: Fix IDE taskfile with cfq scheduler

From: Greg KH
Date: Fri Jul 30 2010 - 13:49:51 EST

2.6.33-stable review patch. If anyone has any objections, please let us know.


From: Mikulas Patocka <mpatocka@xxxxxxxxxx>

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

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

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@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

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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