libata: fix ata_scmd_need_defer()
Fix ata_scmd_need_defer() such that...
* whether NCQ is used or not is exactly determined using the same
criteria as the issue path.
* defer-check is performed in all cases.
This fixes race condition where turning off NCQ on the fly causes
non-NCQ commands sneak into NCQ phase.
Signed-off-by: Tejun Heo <htejun@gmail.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index 7bb782b..aa6cb6d 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -1496,11 +1496,9 @@
static int ata_scmd_need_defer(struct ata_device *dev, int is_io)
{
struct ata_port *ap = dev->ap;
+ int is_ncq = is_io && ata_ncq_enabled(dev);
- if (!(dev->flags & ATA_DFLAG_NCQ))
- return 0;
-
- if (is_io) {
+ if (is_ncq) {
if (!ata_tag_valid(ap->active_tag))
return 0;
} else {