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, 1 deletions

diff --git a/include/linux/ide.h b/include/linux/ide.h
index cb6cd0459a5e..803c1ae31237 100644
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -258,6 +258,7 @@ enum {
         IDE_TFLAG_DYN                   = (1 << 5),
         IDE_TFLAG_FS                    = (1 << 6),
         IDE_TFLAG_MULTI_PIO             = (1 << 7),
+        IDE_TFLAG_SET_XFER              = (1 << 8),
 };
 
 enum {
@@ -294,7 +295,7 @@ struct ide_cmd {
                 } out, in;
         } valid;
 
-        u8                      tf_flags;
+        u16                     tf_flags;
         u8                      ftf_flags;      /* for TASKFILE ioctl */
         int                     protocol;