netpoll: drivers must not enable IRQ unconditionally in their NAPI handler

net/core/netpoll.c::netpoll_send_skb() calls the poll handler when
it is available. As netconsole can be used from almost any context,
IRQ must not be enabled blindly in the NAPI handler of a driver which
supports netpoll.

b57bd06655a028aba7b92e1c19c2093e7fcfb341 fixed the issue for the
8139too.c driver.

Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

4 files changed, 18 insertions, 10 deletions

diff --git a/drivers/net/8139cp.c b/drivers/net/8139cp.c
index 458dd9f830c4..e2cb19b582a1 100644
--- a/drivers/net/8139cp.c
+++ b/drivers/net/8139cp.c
@@ -617,13 +617,15 @@ rx_next:
          * this round of polling
          */
         if (rx_work) {
+                unsigned long flags;
+
                 if (cpr16(IntrStatus) & cp_rx_intr_mask)
                         goto rx_status_loop;
 
-                local_irq_disable();
+                local_irq_save(flags);
                 cpw16_f(IntrMask, cp_intr_mask);
                 __netif_rx_complete(dev);
-                local_irq_enable();
+                local_irq_restore(flags);
 
                 return 0;       /* done */
         }
diff --git a/drivers/net/b44.c b/drivers/net/b44.c
index 474a4e3438db..5eb2ec68393f 100644
--- a/drivers/net/b44.c
+++ b/drivers/net/b44.c
@@ -879,12 +879,14 @@ static int b44_poll(struct net_device *netdev, int *budget)
         }
 
         if (bp->istat & ISTAT_ERRORS) {
-                spin_lock_irq(&bp->lock);
+                unsigned long flags;
+
+                spin_lock_irqsave(&bp->lock, flags);
                 b44_halt(bp);
                 b44_init_rings(bp);
                 b44_init_hw(bp, 1);
                 netif_wake_queue(bp->dev);
-                spin_unlock_irq(&bp->lock);
+                spin_unlock_irqrestore(&bp->lock, flags);
                 done = 1;
         }
 
diff --git a/drivers/net/forcedeth.c b/drivers/net/forcedeth.c
index 439f41338291..820f8c798420 100644
--- a/drivers/net/forcedeth.c
+++ b/drivers/net/forcedeth.c
@@ -2576,14 +2576,15 @@ static int nv_napi_poll(struct net_device *dev, int *budget)
         int pkts, limit = min(*budget, dev->quota);
         struct fe_priv *np = netdev_priv(dev);
         u8 __iomem *base = get_hwbase(dev);
+        unsigned long flags;
 
         pkts = nv_rx_process(dev, limit);
 
         if (nv_alloc_rx(dev)) {
-                spin_lock_irq(&np->lock);
+                spin_lock_irqsave(&np->lock, flags);
                 if (!np->in_shutdown)
                         mod_timer(&np->oom_kick, jiffies + OOM_REFILL);
-                spin_unlock_irq(&np->lock);
+                spin_unlock_irqrestore(&np->lock, flags);
         }
 
         if (pkts < limit) {
@@ -2591,13 +2592,15 @@ static int nv_napi_poll(struct net_device *dev, int *budget)
                 netif_rx_complete(dev);
 
                 /* re-enable receive interrupts */
-                spin_lock_irq(&np->lock);
+                spin_lock_irqsave(&np->lock, flags);
+
                 np->irqmask |= NVREG_IRQ_RX_ALL;
                 if (np->msi_flags & NV_MSI_X_ENABLED)
                         writel(NVREG_IRQ_RX_ALL, base + NvRegIrqMask);
                 else
                         writel(np->irqmask, base + NvRegIrqMask);
-                spin_unlock_irq(&np->lock);
+
+                spin_unlock_irqrestore(&np->lock, flags);
                 return 0;
         } else {
                 /* used up our quantum, so reschedule */
diff --git a/drivers/net/skge.c b/drivers/net/skge.c
index 8a39376f87dc..deedfd5f8226 100644
--- a/drivers/net/skge.c
+++ b/drivers/net/skge.c
@@ -2920,6 +2920,7 @@ static int skge_poll(struct net_device *dev, int *budget)
         struct skge_hw *hw = skge->hw;
         struct skge_ring *ring = &skge->rx_ring;
         struct skge_element *e;
+        unsigned long flags;
         int to_do = min(dev->quota, *budget);
         int work_done = 0;
 
@@ -2957,12 +2958,12 @@ static int skge_poll(struct net_device *dev, int *budget)
         if (work_done >=  to_do)
                 return 1; /* not done */
 
-        spin_lock_irq(&hw->hw_lock);
+        spin_lock_irqsave(&hw->hw_lock, flags);
         __netif_rx_complete(dev);
         hw->intr_mask |= irqmask[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 0;
 }