netdev - [PATCH] pcmcia: worklimit reaches -1

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Message-ID: <49A538EB.8080008@gmail.com>
Date:	Wed, 25 Feb 2009 13:26:19 +0100
From:	Roel Kluin <roel.kluin@...il.com>
To:	"David S. Miller" <davem@...emloft.net>
CC:	netdev@...r.kernel.org, linux-pcmcia@...ts.infradead.org,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: [PATCH] pcmcia: worklimit reaches -1

------------------------------>8-------------8<---------------------------------
with while (--worklimit >= 0); worklimit reaches -1 after the loop. In
3c589_cs.c this caused a warning not to be printed.

In 3c574_cs.c contrastingly, el3_rx() treats worklimit differently:

static int el3_rx(struct net_device *dev, int worklimit)
{
	while (--worklimit >= 0) { ... }
	return worklimit;
}

el3_rx() is only called by function el3_interrupt(): twice:

static irqreturn_t el3_interrupt(int irq, void *dev_id)
{
        int work_budget = max_interrupt_work;
	while(...) {
		if (...)
			work_budget = el3_rx(dev, work_budget);
		if (...)
			work_budget = el3_rx(dev, work_budget);
		if (--work_budget < 0) {
		        ...
		        break;
		}
	}
}
The error path can occur 2 too early.

Signed-off-by: Roel Kluin <roel.kluin@...il.com>
---
el3_rx() calls: lines 839 and 856
el3_interrupt(): line 810

diff --git a/drivers/net/pcmcia/3c574_cs.c b/drivers/net/pcmcia/3c574_cs.c
index e5cb6b1..2404a83 100644
--- a/drivers/net/pcmcia/3c574_cs.c
+++ b/drivers/net/pcmcia/3c574_cs.c
@@ -1035,7 +1035,8 @@ static int el3_rx(struct net_device *dev, int worklimit)
 	DEBUG(3, "%s: in rx_packet(), status %4.4x, rx_status %4.4x.\n",
 		  dev->name, inw(ioaddr+EL3_STATUS), inw(ioaddr+RxStatus));
 	while (!((rx_status = inw(ioaddr + RxStatus)) & 0x8000) &&
-		   (--worklimit >= 0)) {
+			worklimit > 0) {
+		worklimit--;
 		if (rx_status & 0x4000) { /* Error, update stats. */
 			short error = rx_status & 0x3800;
 			dev->stats.rx_errors++;
diff --git a/drivers/net/pcmcia/3c589_cs.c b/drivers/net/pcmcia/3c589_cs.c
index 73ecc65..1e01b8a 100644
--- a/drivers/net/pcmcia/3c589_cs.c
+++ b/drivers/net/pcmcia/3c589_cs.c
@@ -857,7 +857,8 @@ static int el3_rx(struct net_device *dev)
     DEBUG(3, "%s: in rx_packet(), status %4.4x, rx_status %4.4x.\n",
 	  dev->name, inw(ioaddr+EL3_STATUS), inw(ioaddr+RX_STATUS));
     while (!((rx_status = inw(ioaddr + RX_STATUS)) & 0x8000) &&
-	   (--worklimit >= 0)) {
+		    worklimit > 0) {
+	worklimit--;
 	if (rx_status & 0x4000) { /* Error, update stats. */
 	    short error = rx_status & 0x3800;
 	    dev->stats.rx_errors++;
--
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