ide: fix races in handling of user-space SET XFER commands

* Make cmd->tf_flags field 'u16' and add IDE_TFLAG_SET_XFER taskfile flag.

* Update ide_finish_cmd() to set xfer / re-read id if the new flag is set.

* Convert set_xfer_rate() (write handler for /proc/ide/hd?/current_speed)
  and ide_cmd_ioctl() (HDIO_DRIVE_CMD ioctl handler) to use the new flag.

* Remove no longer needed disable_irq_nosync() + enable_irq() from
  ide_config_drive_speed().

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 8 insertions, 1 deletions

diff --git a/drivers/ide/ide-taskfile.c b/drivers/ide/ide-taskfile.c
index 50336d51eebc..cc8633cbe133 100644
--- a/drivers/ide/ide-taskfile.c
+++ b/drivers/ide/ide-taskfile.c
@@ -324,10 +324,17 @@ static void ide_error_cmd(ide_drive_t *drive, struct ide_cmd *cmd)
 void ide_finish_cmd(ide_drive_t *drive, struct ide_cmd *cmd, u8 stat)
 {
         struct request *rq = drive->hwif->rq;
-        u8 err = ide_read_error(drive);
+        u8 err = ide_read_error(drive), nsect = cmd->tf.nsect;
+        u8 set_xfer = !!(cmd->tf_flags & IDE_TFLAG_SET_XFER);
 
         ide_complete_cmd(drive, cmd, stat, err);
         rq->errors = err;
+
+        if (err == 0 && set_xfer) {
+                ide_set_xfer_rate(drive, nsect);
+                ide_driveid_update(drive);
+        }
+
         ide_complete_rq(drive, err ? -EIO : 0, blk_rq_bytes(rq));
 }