Bugzilla: 1022733
Upstream: Submitted for 3.13 and 3.12.y stable
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Date: Tue, 26 Nov 2013 00:40:58 +0100
From: Francois Romieu <romieu@fr.zoreil.com>
To: netdev@vger.kernel.org
Cc: David Miller <davem@davemloft.net>,
"Alex A. Schmidt" <aaschmidt1@gmail.com>,
Michele Baldessari <michele@acksyn.org>,
Jamie Heilman <jamie@audible.transient.net>,
Julia Lawall <Julia.Lawall@lip6.fr>
Subject: [PATCH net 1/1] via-velocity: fix netif_receive_skb use in irq
disabled section.
Message-ID: <20131125234058.GA12566@electric-eye.fr.zoreil.com>
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2fdac010bdcf10a30711b6924612dfc40daf19b8 ("via-velocity.c: update napi
implementation") overlooked an irq disabling spinlock when the Rx part
of the NAPI poll handler was converted from netif_rx to netif_receive_skb.
NAPI Rx processing can be taken out of the locked section with a pair of
napi_{disable / enable} since it only races with the MTU change function.
An heavier rework of the NAPI locking would be able to perform NAPI Tx
before Rx where I simply removed one of velocity_tx_srv calls.
References: https://bugzilla.redhat.com/show_bug.cgi?id=1022733
Fixes: 2fdac010bdcf (via-velocity.c: update napi implementation)
Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Tested-by: Alex A. Schmidt <aaschmidt1@gmail.com>
Cc: Jamie Heilman <jamie@audible.transient.net>
Cc: Michele Baldessari <michele@acksyn.org>
Cc: Julia Lawall <Julia.Lawall@lip6.fr>
---
It is relevant for stable 3.11.x and 3.12.y.
drivers/net/ethernet/via/via-velocity.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
diff --git a/drivers/net/ethernet/via/via-velocity.c b/drivers/net/ethernet/via/via-velocity.c
index d022bf9..ad61d26 100644
--- a/drivers/net/ethernet/via/via-velocity.c
+++ b/drivers/net/ethernet/via/via-velocity.c
@@ -2172,16 +2172,13 @@ static int velocity_poll(struct napi_struct *napi, int budget)
unsigned int rx_done;
unsigned long flags;
- spin_lock_irqsave(&vptr->lock, flags);
/*
* Do rx and tx twice for performance (taken from the VIA
* out-of-tree driver).
*/
- rx_done = velocity_rx_srv(vptr, budget / 2);
- velocity_tx_srv(vptr);
- rx_done += velocity_rx_srv(vptr, budget - rx_done);
+ rx_done = velocity_rx_srv(vptr, budget);
+ spin_lock_irqsave(&vptr->lock, flags);
velocity_tx_srv(vptr);
-
/* If budget not fully consumed, exit the polling mode */
if (rx_done < budget) {
napi_complete(napi);
@@ -2342,6 +2339,8 @@ static int velocity_change_mtu(struct net_device *dev, int new_mtu)
if (ret < 0)
goto out_free_tmp_vptr_1;
+ napi_disable(&vptr->napi);
+
spin_lock_irqsave(&vptr->lock, flags);
netif_stop_queue(dev);
@@ -2362,6 +2361,8 @@ static int velocity_change_mtu(struct net_device *dev, int new_mtu)
velocity_give_many_rx_descs(vptr);
+ napi_enable(&vptr->napi);
+
mac_enable_int(vptr->mac_regs);
netif_start_queue(dev);
--
1.8.3.1
--
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