v2.4.5 -> v2.4.5.1

  - Andreas Dilger: make ext2fs react more gracefully to inode disk
  errors
  - Andrea Arkangeli: fix up alpha compile issues
  - Ingo Molnar: io-apic MP table parsing update and softirq latency
  update
  - Johannes Erdfelt: USB updates
  - Richard Henderson: alpha rawhide irq handling fixes
  - Marcelo, Andrea, Rik: more VM issues
  - Al Viro: fix various ext2 directory handling checks by biting the
  bullet and using the page cache.

1 files changed, 88 insertions, 48 deletions

diff --git a/kernel/softirq.c b/kernel/softirq.c
index fe066399dafa..8981f85281c5 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -52,12 +52,12 @@ asmlinkage void do_softirq()
 	int cpu = smp_processor_id();
 	__u32 active, mask;
 
+	local_irq_disable();
 	if (in_interrupt())
-		return;
+		goto out;
 
 	local_bh_disable();
 
-	local_irq_disable();
 	mask = softirq_mask(cpu);
 	active = softirq_active(cpu) & mask;
 
@@ -71,7 +71,6 @@ restart:
 		local_irq_enable();
 
 		h = softirq_vec;
-		mask &= ~active;
 
 		do {
 			if (active & 1)
@@ -82,12 +81,13 @@ restart:
 
 		local_irq_disable();
 
-		active = softirq_active(cpu);
-		if ((active &= mask) != 0)
+		active = softirq_active(cpu) & mask;
+		if (active)
 			goto retry;
 	}
 
-	local_bh_enable();
+	__local_bh_enable();
+out:
 
 	/* Leave with locally disabled hard irqs. It is critical to close
 	 * window for infinite recursion, while we help local bh count,
@@ -121,6 +121,45 @@ void open_softirq(int nr, void (*action)(struct softirq_action*), void *data)
 
 struct tasklet_head tasklet_vec[NR_CPUS] __cacheline_aligned;
 
+void tasklet_schedule(struct tasklet_struct *t)
+{
+	unsigned long flags;
+	int cpu;
+
+	cpu = smp_processor_id();
+	local_irq_save(flags);
+	/*
+	 * If nobody is running it then add it to this CPU's
+	 * tasklet queue.
+	 */
+	if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state) &&
+						tasklet_trylock(t)) {
+		t->next = tasklet_vec[cpu].list;
+		tasklet_vec[cpu].list = t;
+		__cpu_raise_softirq(cpu, TASKLET_SOFTIRQ);
+		tasklet_unlock(t);
+	}
+	local_irq_restore(flags);
+}
+
+void tasklet_hi_schedule(struct tasklet_struct *t)
+{
+	unsigned long flags;
+	int cpu;
+
+	cpu = smp_processor_id();
+	local_irq_save(flags);
+
+	if (!test_and_set_bit(TASKLET_STATE_SCHED, &t->state) &&
+						tasklet_trylock(t)) {
+		t->next = tasklet_hi_vec[cpu].list;
+		tasklet_hi_vec[cpu].list = t;
+		__cpu_raise_softirq(cpu, HI_SOFTIRQ);
+		tasklet_unlock(t);
+	}
+	local_irq_restore(flags);
+}
+
 static void tasklet_action(struct softirq_action *a)
 {
 	int cpu = smp_processor_id();
@@ -129,37 +168,37 @@ static void tasklet_action(struct softirq_action *a)
 	local_irq_disable();
 	list = tasklet_vec[cpu].list;
 	tasklet_vec[cpu].list = NULL;
-	local_irq_enable();
 
-	while (list != NULL) {
+	while (list) {
 		struct tasklet_struct *t = list;
 
 		list = list->next;
 
-		if (tasklet_trylock(t)) {
-			if (atomic_read(&t->count) == 0) {
-				clear_bit(TASKLET_STATE_SCHED, &t->state);
-
-				t->func(t->data);
-				/*
-				 * talklet_trylock() uses test_and_set_bit that imply
-				 * an mb when it returns zero, thus we need the explicit
-				 * mb only here: while closing the critical section.
-				 */
-#ifdef CONFIG_SMP
-				smp_mb__before_clear_bit();
-#endif
-				tasklet_unlock(t);
-				continue;
-			}
-			tasklet_unlock(t);
+		/*
+		 * A tasklet is only added to the queue while it's
+		 * locked, so no other CPU can have this tasklet
+		 * pending:
+		 */
+		if (!tasklet_trylock(t))
+			BUG();
+repeat:
+		if (!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state))
+			BUG();
+		if (!atomic_read(&t->count)) {
+			local_irq_enable();
+			t->func(t->data);
+			local_irq_disable();
+			/*
+			 * One more run if the tasklet got reactivated:
+			 */
+			if (test_bit(TASKLET_STATE_SCHED, &t->state))
+				goto repeat;
 		}
-		local_irq_disable();
-		t->next = tasklet_vec[cpu].list;
-		tasklet_vec[cpu].list = t;
-		__cpu_raise_softirq(cpu, TASKLET_SOFTIRQ);
-		local_irq_enable();
+		tasklet_unlock(t);
+		if (test_bit(TASKLET_STATE_SCHED, &t->state))
+			tasklet_schedule(t);
 	}
+	local_irq_enable();
 }
 
 
@@ -174,39 +213,40 @@ static void tasklet_hi_action(struct softirq_action *a)
 	local_irq_disable();
 	list = tasklet_hi_vec[cpu].list;
 	tasklet_hi_vec[cpu].list = NULL;
-	local_irq_enable();
 
-	while (list != NULL) {
+	while (list) {
 		struct tasklet_struct *t = list;
 
 		list = list->next;
 
-		if (tasklet_trylock(t)) {
-			if (atomic_read(&t->count) == 0) {
-				clear_bit(TASKLET_STATE_SCHED, &t->state);
-
-				t->func(t->data);
-				tasklet_unlock(t);
-				continue;
-			}
-			tasklet_unlock(t);
+		if (!tasklet_trylock(t))
+			BUG();
+repeat:
+		if (!test_and_clear_bit(TASKLET_STATE_SCHED, &t->state))
+			BUG();
+		if (!atomic_read(&t->count)) {
+			local_irq_enable();
+			t->func(t->data);
+			local_irq_disable();
+			if (test_bit(TASKLET_STATE_SCHED, &t->state))
+				goto repeat;
 		}
-		local_irq_disable();
-		t->next = tasklet_hi_vec[cpu].list;
-		tasklet_hi_vec[cpu].list = t;
-		__cpu_raise_softirq(cpu, HI_SOFTIRQ);
-		local_irq_enable();
+		tasklet_unlock(t);
+		if (test_bit(TASKLET_STATE_SCHED, &t->state))
+			tasklet_hi_schedule(t);
 	}
+	local_irq_enable();
 }
 
 
 void tasklet_init(struct tasklet_struct *t,
 		  void (*func)(unsigned long), unsigned long data)
 {
-	t->func = func;
-	t->data = data;
+	t->next = NULL;
 	t->state = 0;
 	atomic_set(&t->count, 0);
+	t->func = func;
+	t->data = data;
 }
 
 void tasklet_kill(struct tasklet_struct *t)