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From: Greg KH on 30 Jul 2010 15:00
2.6.33-stable review patch. If anyone has any objections, please let us know.

------------------

From: Tim Gardner <tim.gardner(a)canonical.com>

commit d6a574ff6bfb842bdb98065da053881ff527be46 upstream.

Use an irq spinlock to hold off the IRQ handler until
enough early card init is complete such that the handler
can run without faulting.

Signed-off-by: Tim Gardner <tim.gardner(a)canonical.com>
Signed-off-by: John W. Linville <linville(a)tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh(a)suse.de>

---
drivers/net/wireless/hostap/hostap_cs.c | 15 +++++++++++++--
drivers/net/wireless/hostap/hostap_hw.c | 13 +++++++++++++
drivers/net/wireless/hostap/hostap_wlan.h | 2 +-
3 files changed, 27 insertions(+), 3 deletions(-)

--- a/drivers/net/wireless/hostap/hostap_cs.c
+++ b/drivers/net/wireless/hostap/hostap_cs.c
@@ -602,6 +602,7 @@ static int prism2_config(struct pcmcia_d
local_info_t *local;
int ret = 1;
struct hostap_cs_priv *hw_priv;
+ unsigned long flags;

PDEBUG(DEBUG_FLOW, "prism2_config()\n");

@@ -636,6 +637,12 @@ static int prism2_config(struct pcmcia_d
link->dev_node = &hw_priv->node;

/*
+ * Make sure the IRQ handler cannot proceed until at least
+ * dev->base_addr is 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
* irq structure is initialized.
@@ -645,7 +652,7 @@ static int prism2_config(struct pcmcia_d
link->irq.Handler = prism2_interrupt;
ret = pcmcia_request_irq(link, &link->irq);
if (ret)
- goto failed;
+ goto failed_unlock;
}

/*
@@ -655,11 +662,13 @@ static int prism2_config(struct pcmcia_d
*/
ret = pcmcia_request_configuration(link, &link->conf);
if (ret)
- goto failed;
+ goto failed_unlock;

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 */
printk(KERN_INFO "%s: index 0x%02x: ",
dev_info, link->conf.ConfigIndex);
@@ -688,6 +697,8 @@ static int prism2_config(struct pcmcia_d
}
return ret;

+ failed_unlock:
+ spin_unlock_irqrestore(&local->irq_init_lock, flags);
failed:
kfree(hw_priv);
prism2_release((u_long)link);
--- a/drivers/net/wireless/hostap/hostap_hw.c
+++ b/drivers/net/wireless/hostap/hostap_hw.c
@@ -2621,6 +2621,18 @@ static irqreturn_t prism2_interrupt(int
iface = netdev_priv(dev);
local = iface->local;

+ /* Detect early interrupt before driver is fully configued */
+ spin_lock(&local->irq_init_lock);
+ if (!dev->base_addr) {
+ if (net_ratelimit()) {
+ printk(KERN_DEBUG "%s: Interrupt, but dev not configured\n",
+ dev->name);
+ }
+ spin_unlock(&local->irq_init_lock);
+ return IRQ_HANDLED;
+ }
+ spin_unlock(&local->irq_init_lock);
+
prism2_io_debug_add(dev, PRISM2_IO_DEBUG_CMD_INTERRUPT, 0, 0);

if (local->func->card_present && !local->func->card_present(local)) {
@@ -3138,6 +3150,7 @@ prism2_init_local_data(struct prism2_hel
spin_lock_init(&local->cmdlock);
spin_lock_init(&local->baplock);
spin_lock_init(&local->lock);
+ spin_lock_init(&local->irq_init_lock);
mutex_init(&local->rid_bap_mtx);

if (card_idx < 0 || card_idx >= MAX_PARM_DEVICES)
--- a/drivers/net/wireless/hostap/hostap_wlan.h
+++ b/drivers/net/wireless/hostap/hostap_wlan.h
@@ -654,7 +654,7 @@ struct local_info {
rwlock_t iface_lock; /* hostap_interfaces read lock; use write lock
* when removing entries from the list.
* TX and RX paths can use read lock. */
- spinlock_t cmdlock, baplock, lock;
+ spinlock_t cmdlock, baplock, lock, irq_init_lock;
struct mutex rid_bap_mtx;
u16 infofid; /* MAC buffer id for info frame */
/* txfid, intransmitfid, next_txtid, and next_alloc are protected by


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