[PATCH] ipw2200 locking fix

Well, this is not 100% if when the card fires two consecutive
interrupts. Though unlikely, it's better to protect early than seeing
some "weird" bugs one day. I proposed attached patch. If you can help to
test, that will be appreciated (I cannot see the lockdep warning on my
box somehow).

Cc: Frederik Deweerdt <deweerdt@free.fr>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

2 files changed, 33 insertions, 9 deletions

diff --git a/drivers/net/wireless/ipw2200.c b/drivers/net/wireless/ipw2200.c
index 39f82f219749..081a8999666e 100644
--- a/drivers/net/wireless/ipw2200.c
+++ b/drivers/net/wireless/ipw2200.c
@@ -533,7 +533,7 @@ static inline void ipw_clear_bit(struct ipw_priv *priv, u32 reg, u32 mask)
         ipw_write32(priv, reg, ipw_read32(priv, reg) & ~mask);
 }
 
-static inline void ipw_enable_interrupts(struct ipw_priv *priv)
+static inline void __ipw_enable_interrupts(struct ipw_priv *priv)
 {
         if (priv->status & STATUS_INT_ENABLED)
                 return;
@@ -541,7 +541,7 @@ static inline void ipw_enable_interrupts(struct ipw_priv *priv)
         ipw_write32(priv, IPW_INTA_MASK_R, IPW_INTA_MASK_ALL);
 }
 
-static inline void ipw_disable_interrupts(struct ipw_priv *priv)
+static inline void __ipw_disable_interrupts(struct ipw_priv *priv)
 {
         if (!(priv->status & STATUS_INT_ENABLED))
                 return;
@@ -549,6 +549,24 @@ static inline void ipw_disable_interrupts(struct ipw_priv *priv)
         ipw_write32(priv, IPW_INTA_MASK_R, ~IPW_INTA_MASK_ALL);
 }
 
+static inline void ipw_enable_interrupts(struct ipw_priv *priv)
+{
+        unsigned long flags;
+
+        spin_lock_irqsave(&priv->irq_lock, flags);
+        __ipw_enable_interrupts(priv);
+        spin_unlock_irqrestore(&priv->irq_lock, flags);
+}
+
+static inline void ipw_disable_interrupts(struct ipw_priv *priv)
+{
+        unsigned long flags;
+
+        spin_lock_irqsave(&priv->irq_lock, flags);
+        __ipw_disable_interrupts(priv);
+        spin_unlock_irqrestore(&priv->irq_lock, flags);
+}
+
 #ifdef CONFIG_IPW2200_DEBUG
 static char *ipw_error_desc(u32 val)
 {
@@ -1856,7 +1874,7 @@ static void ipw_irq_tasklet(struct ipw_priv *priv)
         unsigned long flags;
         int rc = 0;
 
-        spin_lock_irqsave(&priv->lock, flags);
+        spin_lock_irqsave(&priv->irq_lock, flags);
 
         inta = ipw_read32(priv, IPW_INTA_RW);
         inta_mask = ipw_read32(priv, IPW_INTA_MASK_R);
@@ -1865,6 +1883,10 @@ static void ipw_irq_tasklet(struct ipw_priv *priv)
         /* Add any cached INTA values that need to be handled */
         inta |= priv->isr_inta;
 
+        spin_unlock_irqrestore(&priv->irq_lock, flags);
+
+        spin_lock_irqsave(&priv->lock, flags);
+
         /* handle all the justifications for the interrupt */
         if (inta & IPW_INTA_BIT_RX_TRANSFER) {
                 ipw_rx(priv);
@@ -1993,10 +2015,10 @@ static void ipw_irq_tasklet(struct ipw_priv *priv)
                 IPW_ERROR("Unhandled INTA bits 0x%08x\n", inta & ~handled);
         }
 
+        spin_unlock_irqrestore(&priv->lock, flags);
+
         /* enable all interrupts */
         ipw_enable_interrupts(priv);
-
-        spin_unlock_irqrestore(&priv->lock, flags);
 }
 
 #define IPW_CMD(x) case IPW_CMD_ ## x : return #x
@@ -10460,7 +10482,7 @@ static irqreturn_t ipw_isr(int irq, void *data, struct pt_regs *regs)
         if (!priv)
                 return IRQ_NONE;
 
-        spin_lock(&priv->lock);
+        spin_lock(&priv->irq_lock);
 
         if (!(priv->status & STATUS_INT_ENABLED)) {
                 /* Shared IRQ */
@@ -10482,7 +10504,7 @@ static irqreturn_t ipw_isr(int irq, void *data, struct pt_regs *regs)
         }
 
         /* tell the device to stop sending interrupts */
-        ipw_disable_interrupts(priv);
+        __ipw_disable_interrupts(priv);
 
         /* ack current interrupts */
         inta &= (IPW_INTA_MASK_ALL & inta_mask);
@@ -10493,11 +10515,11 @@ static irqreturn_t ipw_isr(int irq, void *data, struct pt_regs *regs)
 
         tasklet_schedule(&priv->irq_tasklet);
 
-        spin_unlock(&priv->lock);
+        spin_unlock(&priv->irq_lock);
 
         return IRQ_HANDLED;
       none:
-        spin_unlock(&priv->lock);
+        spin_unlock(&priv->irq_lock);
         return IRQ_NONE;
 }
 
@@ -11477,6 +11499,7 @@ static int ipw_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 #ifdef CONFIG_IPW2200_DEBUG
         ipw_debug_level = debug;
 #endif
+        spin_lock_init(&priv->irq_lock);
         spin_lock_init(&priv->lock);
         for (i = 0; i < IPW_IBSS_MAC_HASH_SIZE; i++)
                 INIT_LIST_HEAD(&priv->ibss_mac_hash[i]);
diff --git a/drivers/net/wireless/ipw2200.h b/drivers/net/wireless/ipw2200.h
index 6044c0be2c80..ea12ad66b8e8 100644
--- a/drivers/net/wireless/ipw2200.h
+++ b/drivers/net/wireless/ipw2200.h
@@ -1173,6 +1173,7 @@ struct ipw_priv {
         struct ieee80211_device *ieee;
 
         spinlock_t lock;
+        spinlock_t irq_lock;
         struct mutex mutex;
 
         /* basic pci-network driver stuff */