I'm so sorry for mangled patch.
resending patch with preformat html from thunderbird.


After disabling interrupts, it's possible irq & tasklet is pending or running
This patch eleminates races for down iwlwifi.

Since synchronize_irq can introduce iwl_irq_tasklet, tasklet_kill should be called after doing synchronize_irq.
To avoid races between iwl_synchronize_irq and iwl_irq_tasklet
STATUS_INT_ENABLED flag is needed.

Signed-off-by: Joonwoo Park <[EMAIL PROTECTED]>
---
drivers/net/wireless/iwlwifi/iwl3945-base.c |   33 ++++++++++++++++++++++-----
1 files changed, 27 insertions(+), 6 deletions(-)

diff --git a/drivers/net/wireless/iwlwifi/iwl3945-base.c 
b/drivers/net/wireless/iwlwifi/iwl3945-base.c
index 6e20725..f98cd4f 100644
--- a/drivers/net/wireless/iwlwifi/iwl3945-base.c
+++ b/drivers/net/wireless/iwlwifi/iwl3945-base.c
@@ -4405,6 +4405,14 @@ static void iwl_print_rx_config_cmd(struct iwl_rxon_cmd 
*rxon)
}
#endif

+static void iwl_synchronize_interrupts(struct iwl_priv *priv)
+{
+       synchronize_irq(priv->pci_dev->irq);
+       /* synchornize_irq introduces irq_tasklet,
+        * tasklet_kill should be called after doing synchronize_irq */
+       tasklet_kill(&priv->irq_tasklet);
+}
+
static void iwl_enable_interrupts(struct iwl_priv *priv)
{
        IWL_DEBUG_ISR("Enabling interrupts\n");
@@ -4413,7 +4421,7 @@ static void iwl_enable_interrupts(struct iwl_priv *priv)
        iwl_flush32(priv, CSR_INT_MASK);
}

-static inline void iwl_disable_interrupts(struct iwl_priv *priv)
+static inline void __iwl_disable_interrupts(struct iwl_priv *priv)
{
        clear_bit(STATUS_INT_ENABLED, &priv->status);

@@ -4427,6 +4435,13 @@ static inline void iwl_disable_interrupts(struct 
iwl_priv *priv)
        iwl_flush32(priv, CSR_INT);
        iwl_write32(priv, CSR_FH_INT_STATUS, 0xffffffff);
        iwl_flush32(priv, CSR_FH_INT_STATUS);
+}
+
+static inline void iwl_disable_interrupts(struct iwl_priv *priv)
+{
+       __iwl_disable_interrupts(priv);
+
+       iwl_synchronize_interrupts(priv);

        IWL_DEBUG_ISR("Disabled interrupts\n");
}
@@ -4708,7 +4723,8 @@ static void iwl_irq_tasklet(struct iwl_priv *priv)
                IWL_ERROR("Microcode HW error detected.  Restarting.\n");

                /* Tell the device to stop sending interrupts */
-               iwl_disable_interrupts(priv);
+               __iwl_disable_interrupts(priv);
+               IWL_DEBUG_ISR("Disabled interrupts\n");

                iwl_irq_handle_error(priv);

@@ -4814,8 +4830,11 @@ static void iwl_irq_tasklet(struct iwl_priv *priv)
                IWL_WARNING("   with FH_INT = 0x%08x\n", inta_fh);
        }

-       /* Re-enable all interrupts */
-       iwl_enable_interrupts(priv);
+       /* To avoid race when device goes down,
+        * it should be discarded to enable interrupts */
+       if (test_bit(STATUS_INT_ENABLED, &priv->status))
+               /* Re-enable all interrupts */
+               iwl_enable_interrupts(priv);

#ifdef CONFIG_IWLWIFI_DEBUG
        if (iwl_debug_level & (IWL_DL_ISR)) {
@@ -4876,8 +4895,10 @@ unplugged:
        return IRQ_HANDLED;

 none:
-       /* re-enable interrupts here since we don't have anything to service. */
-       iwl_enable_interrupts(priv);
+       if (test_bit(STATUS_INT_ENABLED, &priv->status))
+               /* re-enable interrupts here since we don't have anything
+                * to service. */
+               iwl_enable_interrupts(priv);
        spin_unlock(&priv->lock);
        return IRQ_NONE;
}
---

Thanks,
Joonwoo

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