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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, NeilBrown <neilb@suse.de>,
        Eugeniu Rosca <erosca@de.adit-jv.com>
Subject: [PATCH 4.9 42/42] SUNRPC: use _bh spinlocking on ->transport_lock
Date:   Tue, 13 Sep 2022 16:08:13 +0200
Message-Id: <20220913140344.525654708@linuxfoundation.org>
In-Reply-To: <20220913140342.228397194@linuxfoundation.org>
References: <20220913140342.228397194@linuxfoundation.org>
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From: "NeilBrown" <neilb@suse.de>

Prior to Linux 5.3, ->transport_lock in sunrpc required the _bh style
spinlocks (when not called from a bottom-half handler).

When upstream 3848e96edf4788f772d83990022fa7023a233d83 was backported to
stable kernels, the spin_lock/unlock calls should have been changed to
the _bh version, but this wasn't noted in the patch and didn't happen.

So convert these lock/unlock calls to the _bh versions.

This patch is required for any stable kernel prior to 5.3 to which the
above mentioned patch was backported.  Namely 4.9.y, 4.14.y, 4.19.y.

Signed-off-by: NeilBrown <neilb@suse.de>
Reported-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Reviewed-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Tested-by: Eugeniu Rosca <erosca@de.adit-jv.com>
---
 net/sunrpc/xprt.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -1451,9 +1451,9 @@ static void xprt_destroy(struct rpc_xprt
 	 * is cleared.  We use ->transport_lock to ensure the mod_timer()
 	 * can only run *before* del_time_sync(), never after.
 	 */
-	spin_lock(&xprt->transport_lock);
+	spin_lock_bh(&xprt->transport_lock);
 	del_timer_sync(&xprt->timer);
-	spin_unlock(&xprt->transport_lock);
+	spin_unlock_bh(&xprt->transport_lock);
 
 	rpc_xprt_debugfs_unregister(xprt);
 	rpc_destroy_wait_queue(&xprt->binding);