netdev - [PATCH net-next] ibmvnic: substitute mb() with dma_wmb() for send

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Message-Id: <20210213023646.55955-1-ljp@linux.ibm.com>
Date:   Fri, 12 Feb 2021 20:36:46 -0600
From:   Lijun Pan <ljp@...ux.ibm.com>
To:     netdev@...r.kernel.org
Cc:     sukadev@...ux.ibm.com, drt@...ux.ibm.com,
        Lijun Pan <ljp@...ux.ibm.com>,
        Thomas Falcon <tlfalcon@...ux.ibm.com>
Subject: [PATCH net-next] ibmvnic: substitute mb() with dma_wmb() for send_*crq* functions

The CRQ and subCRQ descriptors are DMA mapped, so dma_wmb(),
though weaker, is good enough to protect the data structures.

Signed-off-by: Lijun Pan <ljp@...ux.ibm.com>
Acked-by: Thomas Falcon <tlfalcon@...ux.ibm.com>
---
 drivers/net/ethernet/ibm/ibmvnic.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index 7a5e589e7223..927d5f36d308 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -3599,7 +3599,7 @@ static int send_subcrq_indirect(struct ibmvnic_adapter *adapter,
 	int rc;
 
 	/* Make sure the hypervisor sees the complete request */
-	mb();
+	dma_wmb();
 	rc = plpar_hcall_norets(H_SEND_SUB_CRQ_INDIRECT, ua,
 				cpu_to_be64(remote_handle),
 				ioba, num_entries);
@@ -3629,7 +3629,7 @@ static int ibmvnic_send_crq(struct ibmvnic_adapter *adapter,
 	}
 
 	/* Make sure the hypervisor sees the complete request */
-	mb();
+	dma_wmb();
 
 	rc = plpar_hcall_norets(H_SEND_CRQ, ua,
 				cpu_to_be64(u64_crq[0]),
-- 
2.23.0