linux-kernel - [PATCH]skge napi->poll() locking bug

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Message-Id: <200803231020.10030.mitov@issp.bas.bg>
Date:	Sun, 23 Mar 2008 10:20:09 +0200
From:	Marin Mitov <mitov@...p.bas.bg>
To:	linux-kernel@...r.kernel.org
Cc:	Stephen Hemminger <shemminger@...ux-foundation.org>,
	Jeff Garzik <jgarzik@...ox.com>
Subject: [PATCH]skge napi->poll() locking bug

Hi all,

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 :-)

Regards

Marin Mitov

Signed-off-by: Marin Mitov <mitov@...p.bas.bg>
===============================
--- a/drivers/net/skge.c	2008-03-23 09:06:13.000000000 +0200
+++ b/drivers/net/skge.c	2008-03-23 09:24:47.000000000 +0200
@@ -3199,12 +3199,14 @@ static int skge_poll(struct napi_struct 
 	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;


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