From 6a5e984fb0224684cf33d1182f115133db136b78 Mon Sep 17 00:00:00 2001
From: Ben Hutchings <bhutchings@solarflare.com>
Date: Wed, 28 Apr 2010 09:00:35 +0000
Subject: [PATCH] --- yaml --- r: 190374 b: refs/heads/master c:
 aabc5649078310094cbffb430fcbf9c25b6268f9 h: refs/heads/master v: v3

---
 [refs]                        |  2 +-
 trunk/drivers/net/sfc/siena.c | 13 +++++++++++--
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/[refs] b/[refs]
index 051038463603..e47fbe547515 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: c0786693404cffd80ca3cb6e75ee7b35186b2825
+refs/heads/master: aabc5649078310094cbffb430fcbf9c25b6268f9
diff --git a/trunk/drivers/net/sfc/siena.c b/trunk/drivers/net/sfc/siena.c
index 38dcc42c4f79..e0c46f59d1f8 100644
--- a/trunk/drivers/net/sfc/siena.c
+++ b/trunk/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)