ide: Fix IDE taskfile with cfq scheduler

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>

1 files changed, 2 insertions, 4 deletions

diff --git a/drivers/ide/ide-taskfile.c b/drivers/ide/ide-taskfile.c
index cc8633cbe133..67fb73559fd5 100644
--- 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 ide_cmd *cmd, u8 *buf,
 {
         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,