[PATCH v5 1/2] dmaengine: idxd: Protect int_handle field in hw descriptor

From: 'Guanjun'
Date: Mon Dec 11 2023 - 00:38:37 EST


From: Guanjun <guanjun@xxxxxxxxxxxxxxxxx>

The int_handle field in hw descriptor should also be protected
by wmb() before possibly triggering a DMA read.

Fixes: eb0cf33a91b4 (dmaengine: idxd: move interrupt handle assignment)
Signed-off-by: Guanjun <guanjun@xxxxxxxxxxxxxxxxx>
Reviewed-by: Dave Jiang <dave.jiang@xxxxxxxxx>
Reviewed-by: Fenghua Yu <fenghua.yu@xxxxxxxxx>
Reviewed-by: Lijun Pan <lijun.pan@xxxxxxxxx>
---
drivers/dma/idxd/submit.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/dma/idxd/submit.c b/drivers/dma/idxd/submit.c
index c01db23e3333..3f922518e3a5 100644
--- a/drivers/dma/idxd/submit.c
+++ b/drivers/dma/idxd/submit.c
@@ -182,13 +182,6 @@ int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc)

portal = idxd_wq_portal_addr(wq);

- /*
- * The wmb() flushes writes to coherent DMA data before
- * possibly triggering a DMA read. The wmb() is necessary
- * even on UP because the recipient is a device.
- */
- wmb();
-
/*
* Pending the descriptor to the lockless list for the irq_entry
* that we designated the descriptor to.
@@ -199,6 +192,13 @@ int idxd_submit_desc(struct idxd_wq *wq, struct idxd_desc *desc)
llist_add(&desc->llnode, &ie->pending_llist);
}

+ /*
+ * The wmb() flushes writes to coherent DMA data before
+ * possibly triggering a DMA read. The wmb() is necessary
+ * even on UP because the recipient is a device.
+ */
+ wmb();
+
if (wq_dedicated(wq)) {
iosubmit_cmds512(portal, desc->hw, 1);
} else {
--
2.39.3