[PATCH net v3] ibmvnic: Ensure that CRQ entry read are correctly ordered
From: Lijun Pan <hidden>
Date: 2021-01-28 01:35:57
Subsystem:
ibm power sriov virtual nic device driver, linux for powerpc (32-bit and 64-bit), networking drivers, the rest · Maintainers:
Haren Myneni, Rick Lindsley, Madhavan Srinivasan, Michael Ellerman, Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
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 <redacted>
---
v3: reword the comments in the code to make it less confusing.
v2: drop dma_wmb according to Jakub's opinion
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; }
--
2.23.0