From 05b64b364822863974c0121359b01d7ba0f22205 Mon Sep 17 00:00:00 2001 From: Michael Buesch Date: Fri, 28 Sep 2007 16:19:03 +0200 Subject: [PATCH] [B43]: Rewrite pwork locking policy. Implement much easier and more lightweight locking for the periodic work. This also removes the last big busywait loop and replaces it by a sleeping loop. Signed-off-by: Michael Buesch Signed-off-by: John W. Linville Signed-off-by: David S. Miller --- drivers/net/wireless/b43/main.c | 88 ++++++++++++--------------------- 1 file changed, 32 insertions(+), 56 deletions(-) diff --git a/drivers/net/wireless/b43/main.c b/drivers/net/wireless/b43/main.c index a603a154d496..6c80f2e2f4ee 100644 --- a/drivers/net/wireless/b43/main.c +++ b/drivers/net/wireless/b43/main.c @@ -1976,6 +1976,7 @@ void b43_mac_enable(struct b43_wldev *dev) { dev->mac_suspended--; B43_WARN_ON(dev->mac_suspended < 0); + B43_WARN_ON(irqs_disabled()); if (dev->mac_suspended == 0) { b43_write32(dev, B43_MMIO_MACCTL, b43_read32(dev, B43_MMIO_MACCTL) @@ -1986,6 +1987,11 @@ void b43_mac_enable(struct b43_wldev *dev) b43_read32(dev, B43_MMIO_MACCTL); b43_read32(dev, B43_MMIO_GEN_IRQ_REASON); b43_power_saving_ctl_bits(dev, 0); + + /* Re-enable IRQs. */ + spin_lock_irq(&dev->wl->irq_lock); + b43_interrupt_enable(dev, dev->irq_savedstate); + spin_unlock_irq(&dev->wl->irq_lock); } } @@ -1995,23 +2001,34 @@ void b43_mac_suspend(struct b43_wldev *dev) int i; u32 tmp; + might_sleep(); + B43_WARN_ON(irqs_disabled()); B43_WARN_ON(dev->mac_suspended < 0); + if (dev->mac_suspended == 0) { + /* Mask IRQs before suspending MAC. Otherwise + * the MAC stays busy and won't suspend. */ + spin_lock_irq(&dev->wl->irq_lock); + tmp = b43_interrupt_disable(dev, B43_IRQ_ALL); + spin_unlock_irq(&dev->wl->irq_lock); + b43_synchronize_irq(dev); + dev->irq_savedstate = tmp; + b43_power_saving_ctl_bits(dev, B43_PS_AWAKE); b43_write32(dev, B43_MMIO_MACCTL, b43_read32(dev, B43_MMIO_MACCTL) & ~B43_MACCTL_ENABLED); /* force pci to flush the write */ b43_read32(dev, B43_MMIO_MACCTL); - for (i = 10000; i; i--) { + for (i = 40; i; i--) { tmp = b43_read32(dev, B43_MMIO_GEN_IRQ_REASON); if (tmp & B43_IRQ_MAC_SUSPENDED) goto out; - udelay(1); + msleep(1); } b43err(dev->wl, "MAC suspend failed\n"); } - out: +out: dev->mac_suspended++; } @@ -2349,77 +2366,36 @@ static void do_periodic_work(struct b43_wldev *dev) b43_periodic_every15sec(dev); } -/* Estimate a "Badness" value based on the periodic work - * state-machine state. "Badness" is worse (bigger), if the - * periodic work will take longer. +/* Periodic work locking policy: + * The whole periodic work handler is protected by + * wl->mutex. If another lock is needed somewhere in the + * pwork callchain, it's aquired in-place, where it's needed. */ -static int estimate_periodic_work_badness(unsigned int state) -{ - int badness = 0; - - if (state % 8 == 0) /* every 120 sec */ - badness += 10; - if (state % 4 == 0) /* every 60 sec */ - badness += 5; - if (state % 2 == 0) /* every 30 sec */ - badness += 1; - -#define BADNESS_LIMIT 4 - return badness; -} - static void b43_periodic_work_handler(struct work_struct *work) { - struct b43_wldev *dev = - container_of(work, struct b43_wldev, periodic_work.work); - unsigned long flags, delay; - u32 savedirqs = 0; - int badness; + struct b43_wldev *dev = container_of(work, struct b43_wldev, + periodic_work.work); + struct b43_wl *wl = dev->wl; + unsigned long delay; - mutex_lock(&dev->wl->mutex); + mutex_lock(&wl->mutex); if (unlikely(b43_status(dev) != B43_STAT_STARTED)) goto out; if (b43_debug(dev, B43_DBG_PWORK_STOP)) goto out_requeue; - badness = estimate_periodic_work_badness(dev->periodic_state); - if (badness > BADNESS_LIMIT) { - spin_lock_irqsave(&dev->wl->irq_lock, flags); - /* Suspend TX as we don't want to transmit packets while - * we recalibrate the hardware. */ - b43_tx_suspend(dev); - savedirqs = b43_interrupt_disable(dev, B43_IRQ_ALL); - /* Periodic work will take a long time, so we want it to - * be preemtible and release the spinlock. */ - spin_unlock_irqrestore(&dev->wl->irq_lock, flags); - b43_synchronize_irq(dev); + do_periodic_work(dev); - do_periodic_work(dev); - - spin_lock_irqsave(&dev->wl->irq_lock, flags); - b43_interrupt_enable(dev, savedirqs); - b43_tx_resume(dev); - mmiowb(); - spin_unlock_irqrestore(&dev->wl->irq_lock, flags); - } else { - /* Take the global driver lock. This will lock any operation. */ - spin_lock_irqsave(&dev->wl->irq_lock, flags); - - do_periodic_work(dev); - - mmiowb(); - spin_unlock_irqrestore(&dev->wl->irq_lock, flags); - } dev->periodic_state++; out_requeue: if (b43_debug(dev, B43_DBG_PWORK_FAST)) delay = msecs_to_jiffies(50); else delay = round_jiffies(HZ * 15); - queue_delayed_work(dev->wl->hw->workqueue, &dev->periodic_work, delay); + queue_delayed_work(wl->hw->workqueue, &dev->periodic_work, delay); out: - mutex_unlock(&dev->wl->mutex); + mutex_unlock(&wl->mutex); } static void b43_periodic_tasks_setup(struct b43_wldev *dev)