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 <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

Author: Mikulas Patocka

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,