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 <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/ide/ide-taskfile.c

···
 {
 	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.