[PATCH 5.14 030/100] dmaengine: idxd: fix abort status check

From: Greg Kroah-Hartman
Date: Fri Sep 24 2021 - 09:00:06 EST


From: Dave Jiang <dave.jiang@xxxxxxxxx>

[ Upstream commit b60bb6e2bfc192091b8f792781b83b5e0f9324f6 ]

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: 6b4b87f2c31a ("dmaengine: idxd: fix submission race window")
Reported-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
Signed-off-by: Dave Jiang <dave.jiang@xxxxxxxxx>
Link: https://lore.kernel.org/r/162698465160.3560828.18173186265683415384.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/dma/idxd/irq.c | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/dma/idxd/irq.c b/drivers/dma/idxd/irq.c
index 2924819ca8f3..ba839d3569cd 100644
--- a/drivers/dma/idxd/irq.c
+++ b/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;
}
--
2.33.0