2021-07-20 13:35:57

by Justin He

Subject: [PATCH net v2] Revert "qed: fix possible unpaired spin_{un}lock_bh in _qed_mcp_cmd_and_union()"

This reverts commit 6206b7981a36476f4695d661ae139f7db36a802d.

That patch added additional spin_{un}lock_bh(), which was harmless
but pointless. The orginal code path has guaranteed the pair of
spin_{un}lock_bh().

We'd better revert it before we find the exact root cause of the
bug_on mentioned in that patch.

Fixes: 6206b7981a36 ("qed: fix possible unpaired spin_{un}lock_bh in _qed_mcp_cmd_and_union()")
Cc: David S. Miller <[email protected]>
Cc: Prabhakar Kushwaha <[email protected]>
Signed-off-by: Jia He <[email protected]>

---
v2: correct the hash value of reverted commit, and add the fixes tag

drivers/net/ethernet/qlogic/qed/qed_mcp.c | 23 ++++++-----------------
1 file changed, 6 insertions(+), 17 deletions(-)

diff --git a/drivers/net/ethernet/qlogic/qed/qed_mcp.c b/drivers/net/ethernet/qlogic/qed/qed_mcp.c
index 79d879a5d663..4387292c37e2 100644
--- a/drivers/net/ethernet/qlogic/qed/qed_mcp.c
+++ b/drivers/net/ethernet/qlogic/qed/qed_mcp.c
@@ -474,18 +474,14 @@ _qed_mcp_cmd_and_union(struct qed_hwfn *p_hwfn,

spin_lock_bh(&p_hwfn->mcp_info->cmd_lock);

- if (!qed_mcp_has_pending_cmd(p_hwfn)) {
- spin_unlock_bh(&p_hwfn->mcp_info->cmd_lock);
+ if (!qed_mcp_has_pending_cmd(p_hwfn))
break;
- }

rc = qed_mcp_update_pending_cmd(p_hwfn, p_ptt);
- if (!rc) {
- spin_unlock_bh(&p_hwfn->mcp_info->cmd_lock);
+ if (!rc)
break;
- } else if (rc != -EAGAIN) {
+ else if (rc != -EAGAIN)
goto err;
- }

spin_unlock_bh(&p_hwfn->mcp_info->cmd_lock);

@@ -502,8 +498,6 @@ _qed_mcp_cmd_and_union(struct qed_hwfn *p_hwfn,
return -EAGAIN;
}

- spin_lock_bh(&p_hwfn->mcp_info->cmd_lock);
-
/* Send the mailbox command */
qed_mcp_reread_offsets(p_hwfn, p_ptt);
seq_num = ++p_hwfn->mcp_info->drv_mb_seq;
@@ -530,18 +524,14 @@ _qed_mcp_cmd_and_union(struct qed_hwfn *p_hwfn,

spin_lock_bh(&p_hwfn->mcp_info->cmd_lock);

- if (p_cmd_elem->b_is_completed) {
- spin_unlock_bh(&p_hwfn->mcp_info->cmd_lock);
+ if (p_cmd_elem->b_is_completed)
break;
- }

rc = qed_mcp_update_pending_cmd(p_hwfn, p_ptt);
- if (!rc) {
- spin_unlock_bh(&p_hwfn->mcp_info->cmd_lock);
+ if (!rc)
break;
- } else if (rc != -EAGAIN) {
+ else if (rc != -EAGAIN)
goto err;
- }

spin_unlock_bh(&p_hwfn->mcp_info->cmd_lock);
} while (++cnt < max_retries);
@@ -564,7 +554,6 @@ _qed_mcp_cmd_and_union(struct qed_hwfn *p_hwfn,
return -EAGAIN;
}

- spin_lock_bh(&p_hwfn->mcp_info->cmd_lock);
qed_mcp_cmd_del_elem(p_hwfn, p_cmd_elem);
spin_unlock_bh(&p_hwfn->mcp_info->cmd_lock);

--
2.17.1

2021-07-20 14:51:39

by patchwork-bot+netdevbpf

Subject: Re: [PATCH net v2] Revert "qed: fix possible unpaired spin_{un}lock_bh in _qed_mcp_cmd_and_union()"

Hello:

This patch was applied to netdev/net.git (refs/heads/master):

On Tue, 20 Jul 2021 21:26:55 +0800 you wrote:
> This reverts commit 6206b7981a36476f4695d661ae139f7db36a802d.
>
> That patch added additional spin_{un}lock_bh(), which was harmless
> but pointless. The orginal code path has guaranteed the pair of
> spin_{un}lock_bh().
>
> We'd better revert it before we find the exact root cause of the
> bug_on mentioned in that patch.
>
> [...]

Here is the summary with links:
- [net,v2] Revert "qed: fix possible unpaired spin_{un}lock_bh in _qed_mcp_cmd_and_union()"
https://git.kernel.org/netdev/net/c/91bed5565bba

You are awesome, thank you!
--
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