netdev - [net PATCH 1/2] fbnic: Fixup rtnl_lock and devl_lock handling related to mailbox code

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Message-ID: 
 <175616256667.1963577.5543500806256052549.stgit@ahduyck-xeon-server.home.arpa>
Date: Mon, 25 Aug 2025 15:56:06 -0700
From: Alexander Duyck <alexander.duyck@...il.com>
To: AlexanderDuyck@...il.com, netdev@...r.kernel.org
Cc: kuba@...nel.org, kernel-team@...a.com, andrew+netdev@...n.ch,
 pabeni@...hat.com, davem@...emloft.net
Subject: [net PATCH 1/2] fbnic: Fixup rtnl_lock and devl_lock handling related
 to mailbox code

From: Alexander Duyck <alexanderduyck@...com>

The exception handling path for the __fbnic_pm_resume function had a bug in
that it was taking the devlink lock and then exiting to exception handling
instead of waiting until after it released the lock to do so. In order to
handle that I am swapping the placement of the unlock and the exception
handling jump to label so that we don't trigger a deadlock by holding the
lock longer than we need to.

In addition this change applies the same ordering to the rtnl_lock/unlock
calls in the same function as it should make the code easier to follow if
it adheres to a consistent pattern.

Fixes: 82534f446daa ("eth: fbnic: Add devlink dev flash support")
Signed-off-by: Alexander Duyck <alexanderduyck@...com>
---
 drivers/net/ethernet/meta/fbnic/fbnic_pci.c |   13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/net/ethernet/meta/fbnic/fbnic_pci.c b/drivers/net/ethernet/meta/fbnic/fbnic_pci.c
index b70e4cadb37b..a7784deea88f 100644
--- a/drivers/net/ethernet/meta/fbnic/fbnic_pci.c
+++ b/drivers/net/ethernet/meta/fbnic/fbnic_pci.c
@@ -443,11 +443,10 @@ static int __fbnic_pm_resume(struct device *dev)
 
 	/* Re-enable mailbox */
 	err = fbnic_fw_request_mbx(fbd);
+	devl_unlock(priv_to_devlink(fbd));
 	if (err)
 		goto err_free_irqs;
 
-	devl_unlock(priv_to_devlink(fbd));
-
 	/* Only send log history if log buffer is empty to prevent duplicate
 	 * log entries.
 	 */
@@ -464,20 +463,20 @@ static int __fbnic_pm_resume(struct device *dev)
 
 	rtnl_lock();
 
-	if (netif_running(netdev)) {
+	if (netif_running(netdev))
 		err = __fbnic_open(fbn);
-		if (err)
-			goto err_free_mbx;
-	}
 
 	rtnl_unlock();
+	if (err)
+		goto err_free_mbx;
 
 	return 0;
 err_free_mbx:
 	fbnic_fw_log_disable(fbd);
 
-	rtnl_unlock();
+	devl_lock(priv_to_devlink(fbd));
 	fbnic_fw_free_mbx(fbd);
+	devl_unlock(priv_to_devlink(fbd));
 err_free_irqs:
 	fbnic_free_irqs(fbd);
 err_invalidate_uc_addr: