[patch 067/100] sfc: Match calls to netif_napi_add() and netif_napi_del()

Chris Wright
2009-04-23T07:49:47Z

[-- Attachment #1: sfc-match-calls-to-netif_napi_add-and-netif_napi_del.patch --]
[-- Type: text/plain, Size: 1988 bytes --]

-stable review patch. If anyone has any objections, please let us know.
---------------------

From: Ben Hutchings <bhutchings@solarflare.com>

upstream commit: 718cff1eec595ce6ab0635b8160a51ee37d9268d

sfc could call netif_napi_add() multiple times for the same
napi_struct, corrupting the list of napi_structs for the associated
device and leading to a busy-loop on device removal. Move the call to
netif_napi_add() and add a call to netif_napi_del() in the obvious
places.

[bhutchings: backport to 2.6.29]
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
---
We didn't spot this earlier because only netpoll would look at the list,
but this changed with the addition of GRO in 2.6.29. I have no excuse
for not catching it during the .29 release cycle though.

Ben.

drivers/net/sfc/efx.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/net/sfc/efx.c
+++ b/drivers/net/sfc/efx.c
@@ -424,10 +424,6 @@ static void efx_start_channel(struct efx

EFX_LOG(channel->efx, "starting chan %d\n", channel->channel);

- if (!(channel->efx->net_dev->flags & IFF_UP))
- netif_napi_add(channel->napi_dev, &channel->napi_str,
- efx_poll, napi_weight);
-
/* The interrupt handler for this channel may set work_pending
* as soon as we enable it. Make sure it's cleared before
* then. Similarly, make sure it sees the enabled flag set. */
@@ -1273,6 +1269,8 @@ static int efx_init_napi(struct efx_nic

efx_for_each_channel(channel, efx) {
channel->napi_dev = efx->net_dev;
+ netif_napi_add(channel->napi_dev, &channel->napi_str,
+ efx_poll, napi_weight);
rc = efx_lro_init(&channel->lro_mgr, efx);
if (rc)
goto err;
@@ -1289,6 +1287,8 @@ static void efx_fini_napi(struct efx_nic

efx_for_each_channel(channel, efx) {
efx_lro_fini(&channel->lro_mgr);
+ if (channel->napi_dev)
+ netif_napi_del(&channel->napi_str);
channel->napi_dev = NULL;
}
}