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Subject[patch 11/16] b43: Fix some TX/RX locking issues
2.6.25-stable review patch.  If anyone has any objections, please let us
know.

------------------
From: Michael Buesch <mb@bu3sch.de>

commit 21a75d7788f4e29b6c6d28e08f9f0310c4de828d upstream.

This fixes some TX/RX related locking issues.
With this patch applied, some of the PHY transmission errors are fixed.

Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/net/wireless/b43/b43.h | 4 ++++
drivers/net/wireless/b43/main.c | 32 +++++++++++++++++++++++---------
2 files changed, 27 insertions(+), 9 deletions(-)

--- a/drivers/net/wireless/b43/b43.h
+++ b/drivers/net/wireless/b43/b43.h
@@ -628,6 +628,10 @@ struct b43_wl {

struct mutex mutex;
spinlock_t irq_lock;
+ /* R/W lock for data transmission.
+ * Transmissions on 2+ queues can run concurrently, but somebody else
+ * might sync with TX by write_lock_irqsave()'ing. */
+ rwlock_t tx_lock;
/* Lock for LEDs access. */
spinlock_t leds_lock;
/* Lock for SHM access. */
--- a/drivers/net/wireless/b43/main.c
+++ b/drivers/net/wireless/b43/main.c
@@ -622,6 +622,7 @@ static void b43_synchronize_irq(struct b
*/
void b43_dummy_transmission(struct b43_wldev *dev)
{
+ struct b43_wl *wl = dev->wl;
struct b43_phy *phy = &dev->phy;
unsigned int i, max_loop;
u16 value;
@@ -648,6 +649,9 @@ void b43_dummy_transmission(struct b43_w
return;
}

+ spin_lock_irq(&wl->irq_lock);
+ write_lock(&wl->tx_lock);
+
for (i = 0; i < 5; i++)
b43_ram_write(dev, i * 4, buffer[i]);

@@ -688,6 +692,9 @@ void b43_dummy_transmission(struct b43_w
}
if (phy->radio_ver == 0x2050 && phy->radio_rev <= 0x5)
b43_radio_write16(dev, 0x0051, 0x0037);
+
+ write_unlock(&wl->tx_lock);
+ spin_unlock_irq(&wl->irq_lock);
}

static void key_write(struct b43_wldev *dev,
@@ -2592,15 +2599,21 @@ static int b43_op_tx(struct ieee80211_hw
{
struct b43_wl *wl = hw_to_b43_wl(hw);
struct b43_wldev *dev = wl->current_dev;
- int err = -ENODEV;
+ unsigned long flags;
+ int err;

if (unlikely(!dev))
- goto out;
- if (unlikely(b43_status(dev) < B43_STAT_STARTED))
- goto out;
- /* DMA-TX is done without a global lock. */
- err = b43_dma_tx(dev, skb, ctl);
-out:
+ return NETDEV_TX_BUSY;
+
+ /* Transmissions on seperate queues can run concurrently. */
+ read_lock_irqsave(&wl->tx_lock, flags);
+
+ err = -ENODEV;
+ if (likely(b43_status(dev) >= B43_STAT_STARTED))
+ err = b43_dma_tx(dev, skb, ctl);
+
+ read_unlock_irqrestore(&wl->tx_lock, flags);
+
if (unlikely(err))
return NETDEV_TX_BUSY;
return NETDEV_TX_OK;
@@ -3109,7 +3122,9 @@ static void b43_wireless_core_stop(struc
spin_unlock_irqrestore(&wl->irq_lock, flags);
b43_synchronize_irq(dev);

+ write_lock_irqsave(&wl->tx_lock, flags);
b43_set_status(dev, B43_STAT_INITIALIZED);
+ write_unlock_irqrestore(&wl->tx_lock, flags);

mutex_unlock(&wl->mutex);
/* Must unlock as it would otherwise deadlock. No races here.
@@ -3117,8 +3132,6 @@ static void b43_wireless_core_stop(struc
cancel_delayed_work_sync(&dev->periodic_work);
mutex_lock(&wl->mutex);

- ieee80211_stop_queues(wl->hw); //FIXME this could cause a deadlock, as mac80211 seems buggy.
-
b43_mac_suspend(dev);
free_irq(dev->dev->irq, dev);
b43dbg(wl, "Wireless interface stopped\n");
@@ -4084,6 +4097,7 @@ static int b43_wireless_init(struct ssb_
memset(wl, 0, sizeof(*wl));
wl->hw = hw;
spin_lock_init(&wl->irq_lock);
+ rwlock_init(&wl->tx_lock);
spin_lock_init(&wl->leds_lock);
spin_lock_init(&wl->shm_lock);
mutex_init(&wl->mutex);
--


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