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authorBen Hutchings <bhutchings@solarflare.com>2010-04-28 09:00:35 +0000
committerDavid S. Miller <davem@davemloft.net>2010-04-28 12:18:26 -0700
commitaabc5649078310094cbffb430fcbf9c25b6268f9 (patch)
treec633f0c143068b22558547081cf90544846b409f /drivers/net/sfc/siena.c
parentc0786693404cffd80ca3cb6e75ee7b35186b2825 (diff)
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>
Diffstat (limited to 'drivers/net/sfc/siena.c')
-rw-r--r--drivers/net/sfc/siena.c13
1 files changed, 11 insertions, 2 deletions
diff --git a/drivers/net/sfc/siena.c b/drivers/net/sfc/siena.c
index 38dcc42c4f79..e0c46f59d1f8 100644
--- a/drivers/net/sfc/siena.c
+++ b/drivers/net/sfc/siena.c
@@ -456,8 +456,17 @@ static int siena_try_update_nic_stats(struct efx_nic *efx)
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)