sfc: Call netif_napi_add() before registering our interrupt handler
diff mbox

Message ID 1238526464.3254.7.camel@achroite
State Accepted, archived
Delegated to: David Miller
Headers show

Commit Message

Ben Hutchings March 31, 2009, 7:07 p.m. UTC
If we use a shared legacy IRQ then our interrupt handler may be called
as soon as it is registered even though IRQs are disabled on the NIC.
Now that the legacy interrupt handler also checks for event delivery,
it may decide to schedule polling in this case.  Ensure that the NAPI
context is valid but disabled at this point.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
---
Please apply this to net-2.6; the bug it fixes is much easier to hit
following commit a9de9a74c69f75e9456cd6b45ecab44ff4c81d04

Ben.

 drivers/net/sfc/efx.c |    7 +++----
 1 files changed, 3 insertions(+), 4 deletions(-)

Comments

David Miller March 31, 2009, 10:07 p.m. UTC | #1
From: Ben Hutchings <bhutchings@solarflare.com>
Date: Tue, 31 Mar 2009 20:07:44 +0100

> If we use a shared legacy IRQ then our interrupt handler may be called
> as soon as it is registered even though IRQs are disabled on the NIC.
> Now that the legacy interrupt handler also checks for event delivery,
> it may decide to schedule polling in this case.  Ensure that the NAPI
> context is valid but disabled at this point.
> 
> Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>

Applied, thanks.
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Patch
diff mbox

diff --git a/drivers/net/sfc/efx.c b/drivers/net/sfc/efx.c
index 00c23b1..dee23b1 100644
--- a/drivers/net/sfc/efx.c
+++ b/drivers/net/sfc/efx.c
@@ -448,6 +448,9 @@  static void efx_init_channels(struct efx_nic *efx)
 
 		WARN_ON(channel->rx_pkt != NULL);
 		efx_rx_strategy(channel);
+
+		netif_napi_add(channel->napi_dev, &channel->napi_str,
+			       efx_poll, napi_weight);
 	}
 }
 
@@ -462,10 +465,6 @@  static void efx_start_channel(struct efx_channel *channel)
 
 	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. */