From: Marin Mitov <mitov@issp.bas.bg>
Date: Sun, 23 Mar 2008 08:20:09 +0000 (+0200)
Subject: skge napi->poll() locking bug
X-Git-Tag: v2.6.25-rc8~77^2~11
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=6ef2977d414cc196baba0fb53509c5f8cd9154b4;p=platform%2Fkernel%2Flinux-3.10.git

skge napi->poll() locking bug

According to: Documentation/networking/netdevices.txt:

<cite>
napi->poll:
..........
	Context: softirq
	         will be called with interrupts disabled by netconsole.
</cite>

napi->poll() could be called either with interrupts enabled
(in softirq context) or disabled (by netconsole), so the irq flag
should be preserved.

Inspired by Ingo's resent forcedeth patch :-)

Signed-off-by: Marin Mitov <mitov@issp.bas.bg>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
---

diff --git a/drivers/net/skge.c b/drivers/net/skge.c
index 186eb8e..ae52cba 100644
--- a/drivers/net/skge.c
+++ b/drivers/net/skge.c
@@ -3199,12 +3199,14 @@ static int skge_poll(struct napi_struct *napi, int to_do)
 	skge_write8(hw, Q_ADDR(rxqaddr[skge->port], Q_CSR), CSR_START);
 
 	if (work_done < to_do) {
-		spin_lock_irq(&hw->hw_lock);
+		unsigned long flags;
+		
+		spin_lock_irqsave(&hw->hw_lock, flags);
 		__netif_rx_complete(dev, napi);
 		hw->intr_mask |= napimask[skge->port];
 		skge_write32(hw, B0_IMSK, hw->intr_mask);
 		skge_read32(hw, B0_IMSK);
-		spin_unlock_irq(&hw->hw_lock);
+		spin_unlock_irqrestore(&hw->hw_lock, flags);
 	}
 
 	return work_done;