via-velocity: fix netif_receive_skb use in irq disabled section.

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>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/via/via-velocity.c b/drivers/net/ethernet/via/via-velocity.c
index d022bf936572ea857cbcb9f0fded1899077d5a95..ad61d26a44f31d26fc3b6d96f8430a5264e28e6f 100644 (file)
--- 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);