[PATCH 138/150] sfc: Disable soft interrupt handling during efx_device_detach_sync()

Luis Henriques luis.henriques at canonical.com
Tue Mar 26 15:20:37 UTC 2013 -stable review patch.  If anyone has any objections, please let me know.


From: Ben Hutchings <bhutchings at solarflare.com>

commit 35205b211c8d17a8a0b5e8926cb7c73e9a7ef1ad upstream.

efx_device_detach_sync() locks all TX queues before marking the device
detached and thus disabling further TX scheduling.  But it can still
be interrupted by TX completions which then result in TX scheduling in
soft interrupt context.  This will deadlock when it tries to acquire
a TX queue lock that efx_device_detach_sync() already acquired.

To avoid deadlock, we must use netif_tx_{,un}lock_bh().

Signed-off-by: Ben Hutchings <bhutchings at solarflare.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
 drivers/net/ethernet/sfc/efx.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/sfc/efx.h b/drivers/net/ethernet/sfc/efx.h
index 320cf7b..7db0e5b 100644
--- a/drivers/net/ethernet/sfc/efx.h
+++ b/drivers/net/ethernet/sfc/efx.h
@@ -170,9 +170,9 @@ static inline void efx_device_detach_sync(struct efx_nic *efx)
 	 * TX scheduler is stopped when we're done and before
 	 * netif_device_present() becomes false.
-	netif_tx_lock(dev);
+	netif_tx_lock_bh(dev);
-	netif_tx_unlock(dev);
+	netif_tx_unlock_bh(dev);
 #endif /* EFX_EFX_H */

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