2022-09-11 21:14:33

by Haiyang Zhang

Subject: [PATCH net] net: mana: Add rmb after checking owner bits

Per GDMA spec, rmb is necessary after checking owner_bits, before
reading EQ or CQ entries.

Add rmb in these two places to comply with the specs.

Cc: [email protected]
Fixes: ca9c54d2d6a5 ("net: mana: Add a driver for Microsoft Azure Network Adapter (MANA)")
Reported-by: Sinan Kaya <[email protected]>
Signed-off-by: Haiyang Zhang <[email protected]>
---
drivers/net/ethernet/microsoft/mana/gdma_main.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c b/drivers/net/ethernet/microsoft/mana/gdma_main.c
index 5f9240182351..e10b9f8f89e1 100644
--- a/drivers/net/ethernet/microsoft/mana/gdma_main.c
+++ b/drivers/net/ethernet/microsoft/mana/gdma_main.c
@@ -397,6 +397,11 @@ static void mana_gd_process_eq_events(void *arg)
break;
}

+ /* Per GDMA spec, rmb is necessary after checking owner_bits, before
+ * reading eqe.
+ */
+ rmb();
+
mana_gd_process_eqe(eq);

eq->head++;
@@ -1134,6 +1139,11 @@ static int mana_gd_read_cqe(struct gdma_queue *cq, struct gdma_comp *comp)
if (WARN_ON_ONCE(owner_bits != new_bits))
return -1;

+ /* Per GDMA spec, rmb is necessary after checking owner_bits, before
+ * reading completion info
+ */
+ rmb();
+
comp->wq_num = cqe->cqe_info.wq_num;
comp->is_sq = cqe->cqe_info.is_sq;
memcpy(comp->cqe_data, cqe->cqe_data, GDMA_COMP_DATA_SIZE);
--
2.25.1

2022-09-12 23:12:22

by Dexuan Cui

Subject: RE: [PATCH net] net: mana: Add rmb after checking owner bits

> From: LKML haiyangz <[email protected]> On Behalf Of Haiyang Zhang
> Sent: Sunday, September 11, 2022 1:40 PM
> ...
> Per GDMA spec, rmb is necessary after checking owner_bits, before
> reading EQ or CQ entries.
>
> Add rmb in these two places to comply with the specs.
>
> Cc: [email protected]
> Fixes: ca9c54d2d6a5 ("net: mana: Add a driver for Microsoft Azure Network
> Adapter (MANA)")
> Reported-by: Sinan Kaya <[email protected]>
> Signed-off-by: Haiyang Zhang <[email protected]>

Reviewed-by: Dexuan Cui <[email protected]>

2022-09-20 01:21:13

by patchwork-bot+netdevbpf

Subject: Re: [PATCH net] net: mana: Add rmb after checking owner bits

Hello:

This patch was applied to netdev/net.git (master)
by Jakub Kicinski <[email protected]>:

On Sun, 11 Sep 2022 13:40:05 -0700 you wrote:
> Per GDMA spec, rmb is necessary after checking owner_bits, before
> reading EQ or CQ entries.
>
> Add rmb in these two places to comply with the specs.
>
> Cc: [email protected]
> Fixes: ca9c54d2d6a5 ("net: mana: Add a driver for Microsoft Azure Network Adapter (MANA)")
> Reported-by: Sinan Kaya <[email protected]>
> Signed-off-by: Haiyang Zhang <[email protected]>
>
> [...]

Here is the summary with links:
- [net] net: mana: Add rmb after checking owner bits
https://git.kernel.org/netdev/net/c/6fd2c68da55c

You are awesome, thank you!
--
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