[PATCH] airo driver: fix races, oops, etc..

[Benjamin Herrenschmidt <benh@kernel.crashing.org>]

Hi !

Here's a patch against Linus current airo.c, it adds back some fixes I
did during OLS on the previous version of this driver. I couldn't test
this new 'fixed' version though as I don't have the airo card anymore:

 - Initialize the work_struct structures used by the driver
 - Change most of schedule_work() to schedule_delayed_work(). The
   problem with schedule_work() is that the worker_thread will never
   schedule() if the work keeps getting added back to the list by the
   callback, which typically happened with this driver when the xmit
   work gets scheduled while the semaphore was used by a pending
   command. Note that -ac tree has a modified version of this driver
   that gets rid of this "over-smart" work queue stuff and uses normal
   spinlock instead, probably at the expense of some latency...
 - Fix a small signed vs. unsigned char issue
 - Remove bogus pci_module_init(), use pci_register_driver() instead and
   add missing pci_unregister_driver() so the module can now be removed
   without leaving stale references (and thus avoid an oops next time
   the driver list is walked by the device core).

Jeff, if you are ok with these, please send to Linus,

Ben


diff -urN linux-2.5/drivers/net/wireless/airo.c linuxppc-2.5-benh/drivers/net/wireless/airo.c
--- linux-2.5/drivers/net/wireless/airo.c	2003-07-29 08:51:06.000000000 -0400
+++ linuxppc-2.5-benh/drivers/net/wireless/airo.c	2003-07-29 08:54:26.000000000 -0400
@@ -633,7 +633,7 @@
 	u16 SSIDlen;
 	char SSID[32];
 	char apName[16];
-	char bssid[4][ETH_ALEN];
+	unsigned char bssid[4][ETH_ALEN];
 	u16 beaconPeriod;
 	u16 dimPeriod;
 	u16 atimDuration;
@@ -1031,7 +1031,7 @@
 	struct work_struct promisc_task;
 	struct {
 		struct sk_buff *skb;
-		int fid;
+		int fid, hardirq;
 		struct work_struct task;
 	} xmit, xmit11;
 	struct net_device *wifidev;
@@ -1348,7 +1348,12 @@
 		netif_stop_queue(dev);
 		priv->xmit.task.func = (void (*)(void *))airo_do_xmit;
 		priv->xmit.task.data = (void *)dev;
-		schedule_work(&priv->xmit.task);
+		if (priv->xmit.hardirq) {
+			priv->xmit.hardirq = 0;
+			schedule_work(&priv->xmit.task);
+			return;
+		}
+		schedule_delayed_work(&priv->xmit.task, 1);
 		return;
 	}
 	status = transmit_802_3_packet (priv, fids[fid], skb->data);
@@ -1393,6 +1398,7 @@
 		fids[i] |= (len << 16);
 		priv->xmit.skb = skb;
 		priv->xmit.fid = i;
+		priv->xmit.hardirq = 1;
 		airo_do_xmit(dev);
 	}
 	return 0;
@@ -1410,7 +1416,12 @@
 		netif_stop_queue(dev);
 		priv->xmit11.task.func = (void (*)(void *))airo_do_xmit11;
 		priv->xmit11.task.data = (void *)dev;
-		schedule_work(&priv->xmit11.task);
+		if (priv->xmit11.hardirq) {
+			priv->xmit11.hardirq = 0;
+			schedule_work(&priv->xmit11.task);
+			return;
+		}
+		schedule_delayed_work(&priv->xmit11.task, 1);
 		return;
 	}
 	status = transmit_802_11_packet (priv, fids[fid], skb->data);
@@ -1485,7 +1496,7 @@
 	} else {
 		ai->stats_task.func = (void (*)(void *))airo_read_stats;
 		ai->stats_task.data = (void *)ai;
-		schedule_work(&ai->stats_task);
+		schedule_delayed_work(&ai->stats_task, 1);
 	}
 }
 
@@ -1508,7 +1519,7 @@
 	} else {
 		ai->promisc_task.func = (void (*)(void *))airo_end_promisc;
 		ai->promisc_task.data = (void *)ai;
-		schedule_work(&ai->promisc_task);
+		schedule_delayed_work(&ai->promisc_task, 1);
 	}
 }
 
@@ -1524,7 +1535,7 @@
 	} else {
 		ai->promisc_task.func = (void (*)(void *))airo_set_promisc;
 		ai->promisc_task.data = (void *)ai;
-		schedule_work(&ai->promisc_task);
+		schedule_delayed_work(&ai->promisc_task, 1);
 	}
 }
 
@@ -1710,6 +1721,14 @@
 	sema_init(&ai->sem, 1);
 	ai->need_commit = 0;
 	ai->config.len = 0;
+	INIT_WORK(&ai->stats_task, NULL, NULL);
+	INIT_WORK(&ai->promisc_task, NULL, NULL);
+	INIT_WORK(&ai->xmit.task, NULL, NULL);
+	INIT_WORK(&ai->xmit11.task, NULL, NULL);
+	INIT_WORK(&ai->mic_task, NULL, NULL);
+#ifdef WIRELESS_EXT
+	INIT_WORK(&ai->event_task, NULL, NULL);
+#endif
 	rc = add_airo_dev( dev );
 	if (rc)
 		goto err_out_free;
@@ -1859,7 +1878,7 @@
 	} else {
 		ai->event_task.func = (void (*)(void *))airo_send_event;
 		ai->event_task.data = (void *)dev;
-		schedule_work(&ai->event_task);
+		schedule_delayed_work(&ai->event_task, 1);
 	}
 }
 #endif
@@ -1876,7 +1895,7 @@
 	} else {
 		ai->mic_task.func = (void (*)(void *))airo_read_mic;
 		ai->mic_task.data = (void *)ai;
-		schedule_work(&ai->mic_task);
+		schedule_delayed_work(&ai->mic_task, 1);
 	}
 }
 
@@ -4090,7 +4109,7 @@
 
 #ifdef CONFIG_PCI
 	printk( KERN_INFO "airo:  Probing for PCI adapters\n" );
-	rc = pci_module_init(&airo_driver);
+	rc = pci_register_driver(&airo_driver);
 	printk( KERN_INFO "airo:  Finished probing for PCI adapters\n" );
 #endif
 
@@ -4102,6 +4121,7 @@
 
 static void __exit airo_cleanup_module( void )
 {
+	pci_unregister_driver(&airo_driver);
 	while( airo_devices ) {
 		printk( KERN_INFO "airo: Unregistering %s\n", airo_devices->dev->name );
 		stop_airo_card( airo_devices->dev, 1 );
@@ -5160,7 +5180,7 @@
 			      & status_rid.bssid[i][2]
 			      & status_rid.bssid[i][3]
 			      & status_rid.bssid[i][4]
-			      & status_rid.bssid[i][5])!=-1 &&
+			      & status_rid.bssid[i][5])!=0xff &&
 			     (status_rid.bssid[i][0]
 			      | status_rid.bssid[i][1]
 			      | status_rid.bssid[i][2]