sfc: Wait at most 10ms for the MC to finish reading out MAC statistics
The original code would wait indefinitely if MAC stats DMA failed.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Cc: stable@kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/sfc/siena.c b/drivers/net/sfc/siena.c
index 38dcc42..e0c46f5 100644
--- a/drivers/net/sfc/siena.c
+++ b/drivers/net/sfc/siena.c
@@ -456,8 +456,17 @@
static void siena_update_nic_stats(struct efx_nic *efx)
{
- while (siena_try_update_nic_stats(efx) == -EAGAIN)
- cpu_relax();
+ int retry;
+
+ /* If we're unlucky enough to read statistics wduring the DMA, wait
+ * up to 10ms for it to finish (typically takes <500us) */
+ for (retry = 0; retry < 100; ++retry) {
+ if (siena_try_update_nic_stats(efx) == 0)
+ return;
+ udelay(100);
+ }
+
+ /* Use the old values instead */
}
static void siena_start_nic_stats(struct efx_nic *efx)