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From:   "NeilBrown" <neilb@suse.de>
To:     "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
Cc:     "Eugeniu Rosca" <erosca@de.adit-jv.com>,
        "Trond Myklebust" <trondmy@hammerspace.com>,
        "mrodin@de.adit-jv.com" <mrodin@de.adit-jv.com>,
        "stable@vger.kernel.org" <stable@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "roscaeugeniu@gmail.com" <roscaeugeniu@gmail.com>
Subject: [PATCH - stable] SUNRPC: use _bh spinlocking on ->transport_lock
In-reply-to: <Yx107owrRwmIc7pX@kroah.com>
References: <20220418121210.689577360@linuxfoundation.org>,
 <20220418121211.327937970@linuxfoundation.org>,
 <20220907142548.GA9975@lxhi-065>,
 <166259870333.30452.4204968221881228505@noble.neil.brown.name>,
 <f575eeb3000330d9194c6256ad6063bc58f996c7.camel@hammerspace.com>,
 <20220908120931.GA3480@lxhi-065>, <Yx107owrRwmIc7pX@kroah.com>
Date:   Mon, 12 Sep 2022 09:00:52 +1000
Message-id: <166293725263.30452.1720462103844620549@noble.neil.brown.name>
Precedence: bulk


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>
---
 net/sunrpc/xprt.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index d05fa7c36d00..b1abf4848bbc 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -1550,9 +1550,9 @@ static void xprt_destroy(struct rpc_xprt *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);
 
 	/*
 	 * Destroy sockets etc from the system workqueue so they can
-- 
2.37.1