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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org,
        "Vitaly Kuznetsov" <vkuznets@redhat.com>,
        "David S. Miller" <davem@davemloft.net>,
        "Ross Lagerwall" <ross.lagerwall@citrix.com>
Date:   Sun, 09 Dec 2018 21:50:33 +0000
Message-ID: <lsq.1544392233.936009164@decadent.org.uk>
Subject: [PATCH 3.16 047/328] xen-netfront: fix queue name setting
In-Reply-To: <lsq.1544392232.713909046@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

3.16.62-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Vitaly Kuznetsov <vkuznets@redhat.com>

commit 2d408c0d4574b01b9ed45e02516888bf925e11a9 upstream.

Commit f599c64fdf7d ("xen-netfront: Fix race between device setup and
open") changed the initialization order: xennet_create_queues() now
happens before we do register_netdev() so using netdev->name in
xennet_init_queue() is incorrect, we end up with the following in
/proc/interrupts:

 60:        139          0   xen-dyn    -event     eth%d-q0-tx
 61:        265          0   xen-dyn    -event     eth%d-q0-rx
 62:        234          0   xen-dyn    -event     eth%d-q1-tx
 63:          1          0   xen-dyn    -event     eth%d-q1-rx

and this looks ugly. Actually, using early netdev name (even when it's
already set) is also not ideal: nowadays we tend to rename eth devices
and queue name may end up not corresponding to the netdev name.

Use nodename from xenbus device for queue naming: this can't change in VM's
lifetime. Now /proc/interrupts looks like

 62:        202          0   xen-dyn    -event     device/vif/0-q0-tx
 63:        317          0   xen-dyn    -event     device/vif/0-q0-rx
 64:        262          0   xen-dyn    -event     device/vif/0-q1-tx
 65:         17          0   xen-dyn    -event     device/vif/0-q1-rx

Fixes: f599c64fdf7d ("xen-netfront: Fix race between device setup and open")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/net/xen-netfront.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/xen-netfront.c
+++ b/drivers/net/xen-netfront.c
@@ -1646,7 +1646,7 @@ static int xennet_init_queue(struct netf
 	queue->rx_refill_timer.function = rx_refill_timeout;
 
 	snprintf(queue->name, sizeof(queue->name), "%s-q%u",
-		 queue->info->netdev->name, queue->id);
+		 queue->info->xbdev->nodename, queue->id);
 
 	/* Initialise tx_skbs as a free chain containing every entry. */
 	queue->tx_skb_freelist = 0;