From: Lijun Pan <ljp@linux.ibm.com>
To: netdev@vger.kernel.org
Cc: Lijun Pan <ljp@linux.ibm.com>
Subject: [PATCH net 3/3] ibmvnic: Ensure that CRQ entry read/write are correctly ordered
Date: Thu, 21 Jan 2021 00:17:10 -0600 [thread overview]
Message-ID: <20210121061710.53217-4-ljp@linux.ibm.com> (raw)
In-Reply-To: <20210121061710.53217-1-ljp@linux.ibm.com>
Ensure that received Command-Response Queue (CRQ) entries are
properly read/written 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. dma_wmb barrier
is also added to ensure the entire descriptor is written before
future processing.
Fixes: 032c5e82847a ("Driver for IBM System i/p VNIC protocol")
Signed-off-by: Lijun Pan <ljp@linux.ibm.com>
---
drivers/net/ethernet/ibm/ibmvnic.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index 933e8fb71a8b..e947eb068163 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -5090,8 +5090,20 @@ 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) {
+ /* Ensure that the entire CRQ descriptor queue->msgs
+ * has been loaded before reading its contents.
+ * 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;
+ /* Ensure the entire CRQ descriptor is written before
+ * future writing.
+ */
+ dma_wmb();
}
/* remain in tasklet until all
--
2.23.0
prev parent reply other threads:[~2021-01-21 6:19 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-21 6:17 [PATCH net 0/3] fixes the memory barrier for SCRQ/CRQ entry Lijun Pan
2021-01-21 6:17 ` [PATCH net 1/3] ibmvnic: rework to ensure SCRQ entry reads are properly ordered Lijun Pan
2021-01-24 5:08 ` Jakub Kicinski
2021-01-25 4:34 ` Lijun Pan
2021-01-21 6:17 ` [PATCH net 2/3] ibmvnic: remove unnecessary rmb() inside ibmvnic_poll Lijun Pan
2021-01-24 5:09 ` Jakub Kicinski
2021-01-25 4:38 ` Lijun Pan
2021-01-25 20:35 ` Jakub Kicinski
2021-01-21 6:17 ` Lijun Pan [this message]
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