ide: fix ->io_32bit race in ide_taskfile_ioctl()

In ide_taskfile_ioctl(), there was a race condition involving
drive->io_32bit.  It was cleared and restored during ioctl
requests but there was no synchronization with other requests.
So, other requests could execute with the altered ->io_32bit
setting or updated drive->io_32bit could be overwritten by
ide_taskfile_ioctl().

This patch adds IDE_TFLAG_IO_16BIT flag to indicate to
ide_pio_datablock() that 16-bit I/O is needed regardless of
drive->io_32bit settting.

Bart:
- ported it over recent IDE changes

Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/ide.h b/include/linux/ide.h
index f94cf036bd95..c1a8b8bb93ab 100644
--- a/include/linux/ide.h
+++ b/include/linux/ide.h
@@ -931,6 +931,8 @@ enum {
         IDE_TFLAG_IN_TF                 = IDE_TFLAG_IN_NSECT |
                                           IDE_TFLAG_IN_LBA,
         IDE_TFLAG_IN_DEVICE             = (1 << 29),
+        /* force 16-bit I/O operations */
+        IDE_TFLAG_IO_16BIT              = (1 << 30),
 };
 
 struct ide_taskfile {