[PATCH 2/2 V2] b43legacy: Fix locking problem

[Larry Finger <Larry.Finger@lwfinger.net>]

Commit abb1d2bca0fc429c136747a64e675dd4d8906f36 introduced a locking
problem in b43legacy that caused the system to freeze upon booting.

Signed-off-by: Larry Finger@lwfinger.net
---

John,

This is 2.6.31 material. I hope that you do not have trouble with
this patch. While on the road, my normal method is not available.

This is resent as V2 to eliminate some patch offsets that resulted
from the changes in V2 of patch 1.

Larry
---

 main.c |   25 ++++---------------------
 1 file changed, 4 insertions(+), 21 deletions(-)

Index: wireless-testing/drivers/net/wireless/b43legacy/main.c
===================================================================
--- wireless-testing.orig/drivers/net/wireless/b43legacy/main.c
+++ wireless-testing/drivers/net/wireless/b43legacy/main.c
@@ -2767,29 +2767,18 @@ static void b43legacy_op_bss_info_change
 {
 	struct b43legacy_wl *wl = hw_to_b43legacy_wl(hw);
 	struct b43legacy_wldev *dev;
-	struct b43legacy_phy *phy;
 	unsigned long flags;

 	mutex_lock(&wl->mutex);
-	B43legacy_WARN_ON(wl->vif != vif);

 	dev = wl->current_dev;
-	phy = &dev->phy;
-
-	/* Disable IRQs while reconfiguring the device.
-	 * This makes it possible to drop the spinlock throughout
-	 * the reconfiguration process. */
-	spin_lock_irqsave(&wl->irq_lock, flags);
-	if (b43legacy_status(dev) < B43legacy_STAT_STARTED) {
-		spin_unlock_irqrestore(&wl->irq_lock, flags);
+	if (!dev || b43legacy_status(dev) < B43legacy_STAT_STARTED)
 		goto out_unlock_mutex;
-	}
-	b43legacy_write32(dev, B43legacy_MMIO_GEN_IRQ_MASK, 0);

-	if (changed & BSS_CHANGED_BSSID) {
-		spin_unlock_irqrestore(&wl->irq_lock, flags);
-		b43legacy_synchronize_irq(dev);
+	B43legacy_WARN_ON(wl->vif != vif);

+	if (changed & BSS_CHANGED_BSSID) {
+		spin_lock_irqsave(&wl->irq_lock, flags);
 		if (conf->bssid)
 			memcpy(wl->bssid, conf->bssid, ETH_ALEN);
 		else
@@ -2827,12 +2816,6 @@ static void b43legacy_op_bss_info_change
 	}

 	b43legacy_mac_enable(dev);
-
-	spin_lock_irqsave(&wl->irq_lock, flags);
-	b43legacy_write32(dev, B43legacy_MMIO_GEN_IRQ_MASK, dev->irq_mask);
-	/* XXX: why? */
-	mmiowb();
-	spin_unlock_irqrestore(&wl->irq_lock, flags);
  out_unlock_mutex:
 	mutex_unlock(&wl->mutex);
 }