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, 2 insertions, 8 deletions

diff --git a/drivers/ide/ide-proc.c b/drivers/ide/ide-proc.c
index 3242698832a4..021de41655e6 100644
--- a/drivers/ide/ide-proc.c
+++ b/drivers/ide/ide-proc.c
@@ -195,7 +195,6 @@ ide_devset_get(xfer_rate, current_speed);
 static int set_xfer_rate (ide_drive_t *drive, int arg)
 {
         struct ide_cmd cmd;
-        int err;
 
         if (arg < XFER_PIO_0 || arg > XFER_UDMA_6)
                 return -EINVAL;
@@ -206,14 +205,9 @@ static int set_xfer_rate (ide_drive_t *drive, int arg)
         cmd.tf.nsect   = (u8)arg;
         cmd.valid.out.tf = IDE_VALID_FEATURE | IDE_VALID_NSECT;
         cmd.valid.in.tf  = IDE_VALID_NSECT;
+        cmd.tf_flags   = IDE_TFLAG_SET_XFER;
 
-        err = ide_no_data_taskfile(drive, &cmd);
-
-        if (!err) {
-                ide_set_xfer_rate(drive, (u8) arg);
-                ide_driveid_update(drive);
-        }
-        return err;
+        return ide_no_data_taskfile(drive, &cmd);
 }
 
 ide_devset_rw(current_speed, xfer_rate);