sfc: ensure recovery after allocation failures

After failing to allocate a receive buffer the driver may fail to ever
request additional allocations. EF10 NICs require new receive buffers to
be pushed in batches of eight or more. The test for whether a slow fill
should be scheduled failed to take account of this. There is little
downside to *always* requesting a slow fill if we failed to allocate a
buffer, so the condition has been removed completely. The timer that
triggers the request for a refill has also been shortened.

Signed-off-by: Robert Stonehouse <rstonehouse@solarflare.com>
Signed-off-by: Bert Kenward <bkenward@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/sfc/efx.c

@@ -915,7 +915,7 @@ efx_realloc_channels(struct efx_nic *efx, u32 rxq_entries, u32 txq_entries)
 
 void efx_schedule_slow_fill(struct efx_rx_queue *rx_queue)
 {
-	mod_timer(&rx_queue->slow_fill, jiffies + msecs_to_jiffies(100));
+	mod_timer(&rx_queue->slow_fill, jiffies + msecs_to_jiffies(10));
 }
 
 static bool efx_default_channel_want_txqs(struct efx_channel *channel)

drivers/net/ethernet/sfc/rx.c

@@ -360,8 +360,7 @@ void efx_fast_push_rx_descriptors(struct efx_rx_queue *rx_queue, bool atomic)
 		rc = efx_init_rx_buffers(rx_queue, atomic);
 		if (unlikely(rc)) {
 			/* Ensure that we don't leave the rx queue empty */
-			if (rx_queue->added_count == rx_queue->removed_count)
-				efx_schedule_slow_fill(rx_queue);
+			efx_schedule_slow_fill(rx_queue);
 			goto out;
 		}
 	} while ((space -= batch_size) >= batch_size);