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

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

[Jia He]

This reverts commit 2d2f5ded858a4f4659fc63e01dd55605598a8f05.

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.

Cc: David S. Miller <davem@davemloft.net>
Cc: Prabhakar Kushwaha <pkushwaha@marvell.com>
Signed-off-by: Jia He <justin.he@arm.com>
---
 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

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

[Jakub Kicinski]

On Tue, 20 Jul 2021 17:27:39 +0800, Jia He wrote:
> This reverts commit 2d2f5ded858a4f4659fc63e01dd55605598a8f05.

The hash looks wrong, the patch was applied to netdev/net AFAICT,
and the ref there is: 6206b7981a36 ("qed: fix possible unpaired
spin_{un}lock_bh in _qed_mcp_cmd_and_union()")

Please tag the subject with "net":

[PATCH net] Revert ...

> 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.
> 
> Cc: David S. Miller <davem@davemloft.net>
> Cc: Prabhakar Kushwaha <pkushwaha@marvell.com>
> Signed-off-by: Jia He <justin.he@arm.com>

Please also add a Fixes tag.

Fixes: 6206b7981a36 ("qed: fix possible unpaired spin_{un}lock_bh in _qed_mcp_cmd_and_union()")