3.12-stable review patch. If anyone has any objections, please let me know.
------------------
From: Francois Romieu <romieu@xxxxxxxxxxxxx>
[ Upstream commit bc9627e7e918a85e906c1a3f6d01d9b8ef911a96 ]
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@xxxxxxxxxxxxx>
Tested-by: Alex A. Schmidt <aaschmidt1@xxxxxxxxx>
Cc: Jamie Heilman <jamie@xxxxxxxxxxxxxxxxxxxxx>
Cc: Michele Baldessari <michele@xxxxxxxxxx>
Cc: Julia Lawall <Julia.Lawall@xxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/ethernet/via/via-velocity.c | 11 ++++++-----
1 file changed, 6 insertions(+), 5 deletions(-)
--- 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_str
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 ne
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 ne
velocity_give_many_rx_descs(vptr);
+ napi_enable(&vptr->napi);
+
mac_enable_int(vptr->mac_regs);
netif_start_queue(dev);
--
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