[34-longterm 065/247] hostap_cs: fix sleeping function called from invalid context

Paul Gortmaker
2011-06-23T17:35:47Z

From: Stanislaw Gruszka <sgruszka@redhat.com>

-------------------
This is a commit scheduled for the next v2.6.34 longterm release.
If you see a problem with using this for longterm, please comment.
-------------------

commit 4e5518ca53be29c1ec3c00089c97bef36bfed515 upstream.

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
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
drivers/net/wireless/hostap/hostap_cs.c | 15 ++++++---------
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 f33e18e..e436aca 100644
--- a/drivers/net/wireless/hostap/hostap_cs.c
+++ b/drivers/net/wireless/hostap/hostap_cs.c
@@ -638,11 +638,10 @@ static int prism2_config(struct pcmcia_device *link)
link->dev_node = &hw_priv->node;

/*
- * 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);
-
/*
* Allocate an interrupt line. Note that this does not assign a
* handler to the interrupt, unless the 'Handler' member of the
@@ -653,7 +652,7 @@ static int prism2_config(struct pcmcia_device *link)
link->irq.Handler = prism2_interrupt;
ret = pcmcia_request_irq(link, &link->irq);
if (ret)
- goto failed_unlock;
+ goto failed;
}

/*
@@ -663,11 +662,11 @@ static int prism2_config(struct pcmcia_device *link)
*/
ret = pcmcia_request_configuration(link, &link->conf);
if (ret)
- goto failed_unlock;
+ goto failed;

+ spin_lock_irqsave(&local->irq_init_lock, flags);
dev->irq = link->irq.AssignedIRQ;
dev->base_addr = link->io.BasePort1;
-
spin_unlock_irqrestore(&local->irq_init_lock, flags);

/* Finally, report what we've done */
@@ -698,8 +697,6 @@ 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);
--
1.7.4.4