[PATCH] bcm43xx: redesign locking
Redesign the bcm43xx locking.
This is pre-work to get a preemptible periodic work handler.
Signed-off-by: Michael Buesch <mb@bu3sch.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/bcm43xx/bcm43xx.h b/drivers/net/wireless/bcm43xx/bcm43xx.h
index e66fdb1..d8f917c 100644
--- a/drivers/net/wireless/bcm43xx/bcm43xx.h
+++ b/drivers/net/wireless/bcm43xx/bcm43xx.h
@@ -636,6 +636,17 @@
u8 algorithm;
};
+/* Driver initialization status. */
+enum {
+ BCM43xx_STAT_UNINIT, /* Uninitialized. */
+ BCM43xx_STAT_INITIALIZING, /* init_board() in progress. */
+ BCM43xx_STAT_INITIALIZED, /* Fully operational. */
+ BCM43xx_STAT_SHUTTINGDOWN, /* free_board() in progress. */
+ BCM43xx_STAT_RESTARTING, /* controller_restart() called. */
+};
+#define bcm43xx_status(bcm) atomic_read(&(bcm)->init_status)
+#define bcm43xx_set_status(bcm, stat) atomic_set(&(bcm)->init_status, (stat))
+
struct bcm43xx_private {
struct ieee80211_device *ieee;
struct ieee80211softmac_device *softmac;
@@ -646,18 +657,17 @@
void __iomem *mmio_addr;
- /* Do not use the lock directly. Use the bcm43xx_lock* helper
- * functions, to be MMIO-safe. */
- spinlock_t _lock;
+ /* Locking, see "theory of locking" text below. */
+ spinlock_t irq_lock;
+ struct mutex mutex;
- /* Driver status flags. */
- u32 initialized:1, /* init_board() succeed */
- was_initialized:1, /* for PCI suspend/resume. */
- shutting_down:1, /* free_board() in progress */
+ /* Driver initialization status BCM43xx_STAT_*** */
+ atomic_t init_status;
+
+ u16 was_initialized:1, /* for PCI suspend/resume. */
__using_pio:1, /* Internal, use bcm43xx_using_pio(). */
bad_frames_preempt:1, /* Use "Bad Frames Preemption" (default off) */
reg124_set_0x4:1, /* Some variable to keep track of IRQ stuff. */
- powersaving:1, /* TRUE if we are in PowerSaving mode. FALSE otherwise. */
short_preamble:1, /* TRUE, if short preamble is enabled. */
firmware_norelease:1; /* Do not release the firmware. Used on suspend. */
@@ -721,7 +731,7 @@
struct tasklet_struct isr_tasklet;
/* Periodic tasks */
- struct timer_list periodic_tasks;
+ struct work_struct periodic_work;
unsigned int periodic_state;
struct work_struct restart_work;
@@ -746,21 +756,55 @@
#endif
};
-/* bcm43xx_(un)lock() protect struct bcm43xx_private.
- * Note that _NO_ MMIO writes are allowed. If you want to
- * write to the device through MMIO in the critical section, use
- * the *_mmio lock functions.
- * MMIO read-access is allowed, though.
+
+/* *** THEORY OF LOCKING ***
+ *
+ * We have two different locks in the bcm43xx driver.
+ * => bcm->mutex: General sleeping mutex. Protects struct bcm43xx_private
+ * and the device registers.
+ * => bcm->irq_lock: IRQ spinlock. Protects against IRQ handler concurrency.
+ *
+ * We have three types of helper function pairs to utilize these locks.
+ * (Always use the helper functions.)
+ * 1) bcm43xx_{un}lock_noirq():
+ * Takes bcm->mutex. Does _not_ protect against IRQ concurrency,
+ * so it is almost always unsafe, if device IRQs are enabled.
+ * So only use this, if device IRQs are masked.
+ * Locking may sleep.
+ * You can sleep within the critical section.
+ * 2) bcm43xx_{un}lock_irqonly():
+ * Takes bcm->irq_lock. Does _not_ protect against
+ * bcm43xx_lock_noirq() critical sections.
+ * Does only protect against the IRQ handler path and other
+ * irqonly() critical sections.
+ * Locking does not sleep.
+ * You must not sleep within the critical section.
+ * 3) bcm43xx_{un}lock_irqsafe():
+ * This is the cummulative lock and takes both, mutex and irq_lock.
+ * Protects against noirq() and irqonly() critical sections (and
+ * the IRQ handler path).
+ * Locking may sleep.
+ * You must not sleep within the critical section.
*/
-#define bcm43xx_lock(bcm, flags) spin_lock_irqsave(&(bcm)->_lock, flags)
-#define bcm43xx_unlock(bcm, flags) spin_unlock_irqrestore(&(bcm)->_lock, flags)
-/* bcm43xx_(un)lock_mmio() protect struct bcm43xx_private and MMIO.
- * MMIO write-access to the device is allowed.
- * All MMIO writes are flushed on unlock, so it is guaranteed to not
- * interfere with other threads writing MMIO registers.
- */
-#define bcm43xx_lock_mmio(bcm, flags) bcm43xx_lock(bcm, flags)
-#define bcm43xx_unlock_mmio(bcm, flags) do { mmiowb(); bcm43xx_unlock(bcm, flags); } while (0)
+
+/* Lock type 1 */
+#define bcm43xx_lock_noirq(bcm) mutex_lock(&(bcm)->mutex)
+#define bcm43xx_unlock_noirq(bcm) mutex_unlock(&(bcm)->mutex)
+/* Lock type 2 */
+#define bcm43xx_lock_irqonly(bcm, flags) \
+ spin_lock_irqsave(&(bcm)->irq_lock, flags)
+#define bcm43xx_unlock_irqonly(bcm, flags) \
+ spin_unlock_irqrestore(&(bcm)->irq_lock, flags)
+/* Lock type 3 */
+#define bcm43xx_lock_irqsafe(bcm, flags) do { \
+ bcm43xx_lock_noirq(bcm); \
+ bcm43xx_lock_irqonly(bcm, flags); \
+ } while (0)
+#define bcm43xx_unlock_irqsafe(bcm, flags) do { \
+ bcm43xx_unlock_irqonly(bcm, flags); \
+ bcm43xx_unlock_noirq(bcm); \
+ } while (0)
+
static inline
struct bcm43xx_private * bcm43xx_priv(struct net_device *dev)
@@ -843,16 +887,6 @@
return &(bcm->core_80211_ext[bcm->current_80211_core_idx].radio);
}
-/* Are we running in init_board() context? */
-static inline
-int bcm43xx_is_initializing(struct bcm43xx_private *bcm)
-{
- if (bcm->initialized)
- return 0;
- if (bcm->shutting_down)
- return 0;
- return 1;
-}
static inline
struct bcm43xx_lopair * bcm43xx_get_lopair(struct bcm43xx_phyinfo *phy,