From e41aec79e62fa50f940cf222d1e9577f14e149dc Mon Sep 17 00:00:00 2001

From: Lijun Pan <ljp@linux.ibm.com>

Date: Wed, 27 Jan 2021 19:34:42 -0600

Subject: [PATCH] ibmvnic: Ensure that CRQ entry read are correctly ordered

References: bsc#1184114 ltc#192237 bsc#1182485 ltc#191591

Patch-mainline: v5.11-rc6

Git-commit: e41aec79e62fa50f940cf222d1e9577f14e149dc

Ensure that received Command-Response Queue (CRQ) entries are

properly read in order by the driver. dma_rmb barrier has

been added before accessing the CRQ descriptor to ensure

the entire descriptor is read before processing.

Fixes: 032c5e82847a ("Driver for IBM System i/p VNIC protocol")

Signed-off-by: Lijun Pan <ljp@linux.ibm.com>

Link: https://lore.kernel.org/r/20210128013442.88319-1-ljp@linux.ibm.com

Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Acked-by: Michal Suchanek <msuchanek@suse.de>

---

 drivers/net/ethernet/ibm/ibmvnic.c | 6 ++++++

 1 file changed, 6 insertions(+)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c

index 9778c83150f1..8820c98ea891 100644

--- a/drivers/net/ethernet/ibm/ibmvnic.c

+++ b/drivers/net/ethernet/ibm/ibmvnic.c

@@ -5084,6 +5084,12 @@ static void ibmvnic_tasklet(struct tasklet_struct *t)

 	while (!done) {

 		/* Pull all the valid messages off the CRQ */

 		while ((crq = ibmvnic_next_crq(adapter)) != NULL) {

+			/* This barrier makes sure ibmvnic_next_crq()'s

+			 * crq->generic.first & IBMVNIC_CRQ_CMD_RSP is loaded

+			 * before ibmvnic_handle_crq()'s

+			 * switch(gen_crq->first) and switch(gen_crq->cmd).

+			 */

+			dma_rmb();

 			ibmvnic_handle_crq(crq, adapter);

 			crq->generic.first = 0;

 		}

-- 

2.26.2