sfc: Disable soft interrupt handling during efx_device_detach_sync()

[ Upstream commit 35205b211c8d17a8a0b5e8926cb7c73e9a7ef1ad ]

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@solarflare.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/sfc/efx.h b/drivers/net/sfc/efx.h
index dabde2c2ba3f818bc6b5ea37c767cbbfa417966c..76e891e6062413a36854935804b964af0b46fddf 100644 (file)
--- a/drivers/net/sfc/efx.h
+++ b/drivers/net/sfc/efx.h
@@ -158,9 +158,9 @@ 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_device_detach(dev);
-       netif_tx_unlock(dev);
+       netif_tx_unlock_bh(dev);
 }
 
 #endif /* EFX_EFX_H */