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: jsc#SLE-17268 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