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-rw-r--r--arch/x86/kernel/irq_32.c11
-rw-r--r--include/linux/sched.h10
-rw-r--r--kernel/exit.c4
-rw-r--r--kernel/irq/chip.c3
-rw-r--r--kernel/irq/handle.c14
-rw-r--r--kernel/irq/internals.h2
-rw-r--r--kernel/irq/manage.c86
-rw-r--r--kernel/softirq.c18
8 files changed, 66 insertions, 82 deletions
diff --git a/arch/x86/kernel/irq_32.c b/arch/x86/kernel/irq_32.c
index 40fc86161d92..58b7f27cb3e9 100644
--- a/arch/x86/kernel/irq_32.c
+++ b/arch/x86/kernel/irq_32.c
@@ -100,13 +100,8 @@ execute_on_irq_stack(int overflow, struct irq_desc *desc, int irq)
irqctx->tinfo.task = curctx->tinfo.task;
irqctx->tinfo.previous_esp = current_stack_pointer;
- /*
- * Copy the softirq bits in preempt_count so that the
- * softirq checks work in the hardirq context.
- */
- irqctx->tinfo.preempt_count =
- (irqctx->tinfo.preempt_count & ~SOFTIRQ_MASK) |
- (curctx->tinfo.preempt_count & SOFTIRQ_MASK);
+ /* Copy the preempt_count so that the [soft]irq checks work. */
+ irqctx->tinfo.preempt_count = curctx->tinfo.preempt_count;
if (unlikely(overflow))
call_on_stack(print_stack_overflow, isp);
@@ -196,7 +191,7 @@ bool handle_irq(unsigned irq, struct pt_regs *regs)
if (unlikely(!desc))
return false;
- if (!execute_on_irq_stack(overflow, desc, irq)) {
+ if (user_mode_vm(regs) || !execute_on_irq_stack(overflow, desc, irq)) {
if (unlikely(overflow))
print_stack_overflow();
desc->handle_irq(irq, desc);
diff --git a/include/linux/sched.h b/include/linux/sched.h
index f58889b8a608..e345163da657 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1319,6 +1319,11 @@ struct task_struct {
unsigned sched_reset_on_fork:1;
unsigned sched_contributes_to_load:1;
+#ifdef CONFIG_GENERIC_HARDIRQS
+ /* IRQ handler threads */
+ unsigned irq_thread:1;
+#endif
+
pid_t pid;
pid_t tgid;
@@ -1427,11 +1432,6 @@ struct task_struct {
* mempolicy */
spinlock_t alloc_lock;
-#ifdef CONFIG_GENERIC_HARDIRQS
- /* IRQ handler threads */
- struct irqaction *irqaction;
-#endif
-
/* Protection of the PI data structures: */
raw_spinlock_t pi_lock;
diff --git a/kernel/exit.c b/kernel/exit.c
index 4b4042f9bc6a..752d2c0abd19 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -935,8 +935,6 @@ void do_exit(long code)
schedule();
}
- exit_irq_thread();
-
exit_signals(tsk); /* sets PF_EXITING */
/*
* tsk->flags are checked in the futex code to protect against
@@ -945,6 +943,8 @@ void do_exit(long code)
smp_mb();
raw_spin_unlock_wait(&tsk->pi_lock);
+ exit_irq_thread();
+
if (unlikely(in_atomic()))
printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",
current->comm, task_pid_nr(current),
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index fb7db75ee0c8..25784d630a12 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -61,8 +61,7 @@ int irq_set_irq_type(unsigned int irq, unsigned int type)
return -EINVAL;
type &= IRQ_TYPE_SENSE_MASK;
- if (type != IRQ_TYPE_NONE)
- ret = __irq_set_trigger(desc, irq, type);
+ ret = __irq_set_trigger(desc, irq, type);
irq_put_desc_busunlock(desc, flags);
return ret;
}
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index 470d08c82bbe..6ff84e6a954c 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -60,7 +60,7 @@ static void irq_wake_thread(struct irq_desc *desc, struct irqaction *action)
* device interrupt, so no irq storm is lurking. If the
* RUNTHREAD bit is already set, nothing to do.
*/
- if (test_bit(IRQTF_DIED, &action->thread_flags) ||
+ if ((action->thread->flags & PF_EXITING) ||
test_and_set_bit(IRQTF_RUNTHREAD, &action->thread_flags))
return;
@@ -110,6 +110,18 @@ static void irq_wake_thread(struct irq_desc *desc, struct irqaction *action)
* threads_oneshot untouched and runs the thread another time.
*/
desc->threads_oneshot |= action->thread_mask;
+
+ /*
+ * We increment the threads_active counter in case we wake up
+ * the irq thread. The irq thread decrements the counter when
+ * it returns from the handler or in the exit path and wakes
+ * up waiters which are stuck in synchronize_irq() when the
+ * active count becomes zero. synchronize_irq() is serialized
+ * against this code (hard irq handler) via IRQS_INPROGRESS
+ * like the finalize_oneshot() code. See comment above.
+ */
+ atomic_inc(&desc->threads_active);
+
wake_up_process(action->thread);
}
diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h
index 40378ff877e7..8e5c56b3b7d9 100644
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -20,14 +20,12 @@ extern bool noirqdebug;
/*
* Bits used by threaded handlers:
* IRQTF_RUNTHREAD - signals that the interrupt handler thread should run
- * IRQTF_DIED - handler thread died
* IRQTF_WARNED - warning "IRQ_WAKE_THREAD w/o thread_fn" has been printed
* IRQTF_AFFINITY - irq thread is requested to adjust affinity
* IRQTF_FORCED_THREAD - irq action is force threaded
*/
enum {
IRQTF_RUNTHREAD,
- IRQTF_DIED,
IRQTF_WARNED,
IRQTF_AFFINITY,
IRQTF_FORCED_THREAD,
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 0f0d4704ddd8..b0ccd1ac2d6a 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -759,6 +759,13 @@ static irqreturn_t irq_thread_fn(struct irq_desc *desc,
return ret;
}
+static void wake_threads_waitq(struct irq_desc *desc)
+{
+ if (atomic_dec_and_test(&desc->threads_active) &&
+ waitqueue_active(&desc->wait_for_threads))
+ wake_up(&desc->wait_for_threads);
+}
+
/*
* Interrupt handler thread
*/
@@ -771,57 +778,41 @@ static int irq_thread(void *data)
struct irq_desc *desc = irq_to_desc(action->irq);
irqreturn_t (*handler_fn)(struct irq_desc *desc,
struct irqaction *action);
- int wake;
- if (force_irqthreads & test_bit(IRQTF_FORCED_THREAD,
+ if (force_irqthreads && test_bit(IRQTF_FORCED_THREAD,
&action->thread_flags))
handler_fn = irq_forced_thread_fn;
else
handler_fn = irq_thread_fn;
sched_setscheduler(current, SCHED_FIFO, &param);
- current->irqaction = action;
+ current->irq_thread = 1;
while (!irq_wait_for_interrupt(action)) {
+ irqreturn_t action_ret;
irq_thread_check_affinity(desc, action);
- atomic_inc(&desc->threads_active);
+ action_ret = handler_fn(desc, action);
+ if (!noirqdebug)
+ note_interrupt(action->irq, desc, action_ret);
- raw_spin_lock_irq(&desc->lock);
- if (unlikely(irqd_irq_disabled(&desc->irq_data))) {
- /*
- * CHECKME: We might need a dedicated
- * IRQ_THREAD_PENDING flag here, which
- * retriggers the thread in check_irq_resend()
- * but AFAICT IRQS_PENDING should be fine as it
- * retriggers the interrupt itself --- tglx
- */
- desc->istate |= IRQS_PENDING;
- raw_spin_unlock_irq(&desc->lock);
- } else {
- irqreturn_t action_ret;
-
- raw_spin_unlock_irq(&desc->lock);
- action_ret = handler_fn(desc, action);
- if (!noirqdebug)
- note_interrupt(action->irq, desc, action_ret);
- }
-
- wake = atomic_dec_and_test(&desc->threads_active);
-
- if (wake && waitqueue_active(&desc->wait_for_threads))
- wake_up(&desc->wait_for_threads);
+ wake_threads_waitq(desc);
}
- /* Prevent a stale desc->threads_oneshot */
- irq_finalize_oneshot(desc, action, true);
-
/*
- * Clear irqaction. Otherwise exit_irq_thread() would make
+ * This is the regular exit path. __free_irq() is stopping the
+ * thread via kthread_stop() after calling
+ * synchronize_irq(). So neither IRQTF_RUNTHREAD nor the
+ * oneshot mask bit can be set. We cannot verify that as we
+ * cannot touch the oneshot mask at this point anymore as
+ * __setup_irq() might have given out currents thread_mask
+ * again.
+ *
+ * Clear irq_thread. Otherwise exit_irq_thread() would make
* fuzz about an active irq thread going into nirvana.
*/
- current->irqaction = NULL;
+ current->irq_thread = 0;
return 0;
}
@@ -832,27 +823,28 @@ void exit_irq_thread(void)
{
struct task_struct *tsk = current;
struct irq_desc *desc;
+ struct irqaction *action;
- if (!tsk->irqaction)
+ if (!tsk->irq_thread)
return;
+ action = kthread_data(tsk);
+
printk(KERN_ERR
"exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
- tsk->comm ? tsk->comm : "", tsk->pid, tsk->irqaction->irq);
+ tsk->comm ? tsk->comm : "", tsk->pid, action->irq);
- desc = irq_to_desc(tsk->irqaction->irq);
+ desc = irq_to_desc(action->irq);
/*
- * Prevent a stale desc->threads_oneshot. Must be called
- * before setting the IRQTF_DIED flag.
+ * If IRQTF_RUNTHREAD is set, we need to decrement
+ * desc->threads_active and wake possible waiters.
*/
- irq_finalize_oneshot(desc, tsk->irqaction, true);
+ if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
+ wake_threads_waitq(desc);
- /*
- * Set the THREAD DIED flag to prevent further wakeups of the
- * soon to be gone threaded handler.
- */
- set_bit(IRQTF_DIED, &tsk->irqaction->flags);
+ /* Prevent a stale desc->threads_oneshot */
+ irq_finalize_oneshot(desc, action, true);
}
static void irq_setup_forced_threading(struct irqaction *new)
@@ -1135,8 +1127,7 @@ out_thread:
struct task_struct *t = new->thread;
new->thread = NULL;
- if (likely(!test_bit(IRQTF_DIED, &new->thread_flags)))
- kthread_stop(t);
+ kthread_stop(t);
put_task_struct(t);
}
out_mput:
@@ -1246,8 +1237,7 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
#endif
if (action->thread) {
- if (!test_bit(IRQTF_DIED, &action->thread_flags))
- kthread_stop(action->thread);
+ kthread_stop(action->thread);
put_task_struct(action->thread);
}
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 4eb3a0fa351e..c82d95a022ef 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -310,31 +310,21 @@ void irq_enter(void)
__irq_enter();
}
-#ifdef __ARCH_IRQ_EXIT_IRQS_DISABLED
static inline void invoke_softirq(void)
{
- if (!force_irqthreads)
+ if (!force_irqthreads) {
+#ifdef __ARCH_IRQ_EXIT_IRQS_DISABLED
__do_softirq();
- else {
- __local_bh_disable((unsigned long)__builtin_return_address(0),
- SOFTIRQ_OFFSET);
- wakeup_softirqd();
- __local_bh_enable(SOFTIRQ_OFFSET);
- }
-}
#else
-static inline void invoke_softirq(void)
-{
- if (!force_irqthreads)
do_softirq();
- else {
+#endif
+ } else {
__local_bh_disable((unsigned long)__builtin_return_address(0),
SOFTIRQ_OFFSET);
wakeup_softirqd();
__local_bh_enable(SOFTIRQ_OFFSET);
}
}
-#endif
/*
* Exit an interrupt context. Process softirqs if needed and possible:
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