[PATCH net-2.6] sfc: Fix polling for slow MCDI operations

[PATCH net-2.6] sfc: Fix polling for slow MCDI operations

[Ben Hutchings]

When the interface is down and we are using polled mode for MCDI
operations, we busy-wait for completion for approximately 1 jiffy
using udelay() and then back off to schedule().  But the completion
will not wake the task, since we are using polled mode!  We must use
schedule_timeout_uninterruptible() instead.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
---
 drivers/net/sfc/mcdi.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/net/sfc/mcdi.c b/drivers/net/sfc/mcdi.c
index 683353b..0d4eba7 100644
--- a/drivers/net/sfc/mcdi.c
+++ b/drivers/net/sfc/mcdi.c
@@ -142,8 +142,9 @@ static int efx_mcdi_poll(struct efx_nic *efx)
 		if (spins != 0) {
 			--spins;
 			udelay(1);
-		} else
-			schedule();
+		} else {
+			schedule_timeout_uninterruptible(1);
+		}
 
 		time = get_seconds();
 
-- 
1.5.5

-- 
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.

Re: [PATCH net-2.6] sfc: Fix polling for slow MCDI operations

[David Miller]

From: Ben Hutchings <bhutchings@solarflare.com>
Date: Wed, 13 Jan 2010 14:34:25 +0000

> When the interface is down and we are using polled mode for MCDI
> operations, we busy-wait for completion for approximately 1 jiffy
> using udelay() and then back off to schedule().  But the completion
> will not wake the task, since we are using polled mode!  We must use
> schedule_timeout_uninterruptible() instead.
> 
> Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>

Applied.