dmaengine: idxd: fix abort status check

[ Upstream commit b60bb6e ]

Coverity static analysis of linux-next found issue.

The check (status == IDXD_COMP_DESC_ABORT) is always false since status
was previously masked with 0x7f and IDXD_COMP_DESC_ABORT is 0xff.

Fixes: 6b4b87f ("dmaengine: idxd: fix submission race window")
Reported-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/162698465160.3560828.18173186265683415384.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

drivers/dma/idxd/irq.c

@@ -269,7 +269,11 @@ static int irq_process_pending_llist(struct idxd_irq_entry *irq_entry,
 		u8 status = desc->completion->status & DSA_COMP_STATUS_MASK;
 
 		if (status) {
-			if (unlikely(status == IDXD_COMP_DESC_ABORT)) {
+			/*
+			 * Check against the original status as ABORT is software defined
+			 * and 0xff, which DSA_COMP_STATUS_MASK can mask out.
+			 */
+			if (unlikely(desc->completion->status == IDXD_COMP_DESC_ABORT)) {
 				complete_desc(desc, IDXD_COMPLETE_ABORT);
 				(*processed)++;
 				continue;
@@ -333,7 +337,11 @@ static int irq_process_work_list(struct idxd_irq_entry *irq_entry,
 	list_for_each_entry(desc, &flist, list) {
 		u8 status = desc->completion->status & DSA_COMP_STATUS_MASK;
 
-		if (unlikely(status == IDXD_COMP_DESC_ABORT)) {
+		/*
+		 * Check against the original status as ABORT is software defined
+		 * and 0xff, which DSA_COMP_STATUS_MASK can mask out.
+		 */
+		if (unlikely(desc->completion->status == IDXD_COMP_DESC_ABORT)) {
 			complete_desc(desc, IDXD_COMPLETE_ABORT);
 			continue;
 		}