hostap_cs: fix sleeping function called from invalid context

pcmcia_request_irq() and pcmcia_enable_device() are intended
to be called from process context (first function allocate memory
with GFP_KERNEL, second take a mutex). We can not take spin lock
and call them.

It's safe to move spin lock after pcmcia_enable_device() as we
still hold off IRQ until dev->base_addr is 0 and driver will
not proceed with interrupts when is not ready.

Patch resolves:
https://bugzilla.redhat.com/show_bug.cgi?id=643758

Reported-and-tested-by: rbugz@biobind.com
Cc: stable@kernel.org  # 2.6.34+
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 6 insertions, 9 deletions

diff --git a/drivers/net/wireless/hostap/hostap_cs.c b/drivers/net/wireless/hostap/hostap_cs.c
index bd8a4134edeb..2176edede39b 100644
--- a/drivers/net/wireless/hostap/hostap_cs.c
+++ b/drivers/net/wireless/hostap/hostap_cs.c
@@ -518,22 +518,21 @@ static int prism2_config(struct pcmcia_device *link)
         hw_priv->link = link;
 
         /*
-         * Make sure the IRQ handler cannot proceed until at least
-         * dev->base_addr is initialized.
+         * We enable IRQ here, but IRQ handler will not proceed
+         * until dev->base_addr is set below. This protect us from
+         * receive interrupts when driver is not initialized.
          */
-        spin_lock_irqsave(&local->irq_init_lock, flags);
-
         ret = pcmcia_request_irq(link, prism2_interrupt);
         if (ret)
-                goto failed_unlock;
+                goto failed;
 
         ret = pcmcia_enable_device(link);
         if (ret)
-                goto failed_unlock;
+                goto failed;
 
+        spin_lock_irqsave(&local->irq_init_lock, flags);
         dev->irq = link->irq;
         dev->base_addr = link->resource[0]->start;
-
         spin_unlock_irqrestore(&local->irq_init_lock, flags);
 
         local->shutdown = 0;
@@ -546,8 +545,6 @@ static int prism2_config(struct pcmcia_device *link)
 
         return ret;
 
- failed_unlock:
-        spin_unlock_irqrestore(&local->irq_init_lock, flags);
  failed:
         kfree(hw_priv);
         prism2_release((u_long)link);