ide: Remove ide_spin_wait_hwgroup() and use special requests instead

Use a special request for serialisation purposes and get rid of the
awkward ide_spin_wait_hwgroup(). This also involves converting the
ide_devset structure so it can be shared by the /proc and the ioctl code.

Signed-off-by: Elias Oltmanns <eo@nebensachen.de>
[bart: use rq->cmd[] directly]
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/ide-io.c b/drivers/ide/ide-io.c
index ec6664b..1c51949 100644
--- a/drivers/ide/ide-io.c
+++ b/drivers/ide/ide-io.c
@@ -716,9 +716,49 @@
  	return ide_stopped;
 }
 
+int ide_devset_execute(ide_drive_t *drive, const struct ide_devset *setting,
+		       int arg)
+{
+	struct request_queue *q = drive->queue;
+	struct request *rq;
+	int ret = 0;
+
+	if (!(setting->flags & DS_SYNC))
+		return setting->set(drive, arg);
+
+	rq = blk_get_request(q, READ, GFP_KERNEL);
+	if (!rq)
+		return -ENOMEM;
+
+	rq->cmd_type = REQ_TYPE_SPECIAL;
+	rq->cmd_len = 5;
+	rq->cmd[0] = REQ_DEVSET_EXEC;
+	*(int *)&rq->cmd[1] = arg;
+	rq->special = setting->set;
+
+	if (blk_execute_rq(q, NULL, rq, 0))
+		ret = rq->errors;
+	blk_put_request(rq);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(ide_devset_execute);
+
 static ide_startstop_t ide_special_rq(ide_drive_t *drive, struct request *rq)
 {
 	switch (rq->cmd[0]) {
+	case REQ_DEVSET_EXEC:
+	{
+		int err, (*setfunc)(ide_drive_t *, int) = rq->special;
+
+		err = setfunc(drive, *(int *)&rq->cmd[1]);
+		if (err)
+			rq->errors = err;
+		else
+			err = 1;
+		ide_end_request(drive, err, 0);
+		return ide_stopped;
+	}
 	case REQ_DRIVE_RESET:
 		return ide_do_reset(drive);
 	default: