From 52abb700e16a9aa4cbc03f3d7f80206cbbc80680 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 6 Mar 2012 23:18:54 +0100 Subject: genirq: Clear action->thread_mask if IRQ_ONESHOT is not set Xommit ac5637611(genirq: Unmask oneshot irqs when thread was not woken) fails to unmask when a !IRQ_ONESHOT threaded handler is handled by handle_level_irq. This happens because thread_mask is or'ed unconditionally in irq_wake_thread(), but for !IRQ_ONESHOT interrupts never cleared. So the check for !desc->thread_active fails and keeps the interrupt disabled. Keep the thread_mask zero for !IRQ_ONESHOT interrupts. Document the thread_mask magic while at it. Reported-and-tested-by: Sven Joachim Reported-and-tested-by: Stefan Lippers-Hollmann Cc: stable@vger.kernel.org Signed-off-by: Thomas Gleixner Signed-off-by: Linus Torvalds --- kernel/irq/manage.c | 44 ++++++++++++++++++++++++++++++++++++++------ 1 file changed, 38 insertions(+), 6 deletions(-) (limited to 'kernel/irq/manage.c') diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 32313c084442..0f0d4704ddd8 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -985,6 +985,11 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) /* add new interrupt at end of irq queue */ do { + /* + * Or all existing action->thread_mask bits, + * so we can find the next zero bit for this + * new action. + */ thread_mask |= old->thread_mask; old_ptr = &old->next; old = *old_ptr; @@ -993,14 +998,41 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) } /* - * Setup the thread mask for this irqaction. Unlikely to have - * 32 resp 64 irqs sharing one line, but who knows. + * Setup the thread mask for this irqaction for ONESHOT. For + * !ONESHOT irqs the thread mask is 0 so we can avoid a + * conditional in irq_wake_thread(). */ - if (new->flags & IRQF_ONESHOT && thread_mask == ~0UL) { - ret = -EBUSY; - goto out_mask; + if (new->flags & IRQF_ONESHOT) { + /* + * Unlikely to have 32 resp 64 irqs sharing one line, + * but who knows. + */ + if (thread_mask == ~0UL) { + ret = -EBUSY; + goto out_mask; + } + /* + * The thread_mask for the action is or'ed to + * desc->thread_active to indicate that the + * IRQF_ONESHOT thread handler has been woken, but not + * yet finished. The bit is cleared when a thread + * completes. When all threads of a shared interrupt + * line have completed desc->threads_active becomes + * zero and the interrupt line is unmasked. See + * handle.c:irq_wake_thread() for further information. + * + * If no thread is woken by primary (hard irq context) + * interrupt handlers, then desc->threads_active is + * also checked for zero to unmask the irq line in the + * affected hard irq flow handlers + * (handle_[fasteoi|level]_irq). + * + * The new action gets the first zero bit of + * thread_mask assigned. See the loop above which or's + * all existing action->thread_mask bits. + */ + new->thread_mask = 1 << ffz(thread_mask); } - new->thread_mask = 1 << ffz(thread_mask); if (!shared) { init_waitqueue_head(&desc->wait_for_threads); -- cgit v1.2.3 From 540b60e24f3f4781d80e47122f0c4486a03375b8 Mon Sep 17 00:00:00 2001 From: Alexander Gordeev Date: Fri, 9 Mar 2012 14:59:13 +0100 Subject: genirq: Fix incorrect check for forced IRQ thread handler We do not want a bitwise AND between boolean operands Signed-off-by: Alexander Gordeev Cc: Oleg Nesterov Link: http://lkml.kernel.org/r/20120309135912.GA2114@dhcp-26-207.brq.redhat.com Cc: stable@vger.kernel.org Signed-off-by: Thomas Gleixner --- kernel/irq/manage.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/irq/manage.c') diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index a9a9dbe49fea..c0730ad8a117 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -773,7 +773,7 @@ static int irq_thread(void *data) 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 -- cgit v1.2.3 From 4bcdf1d0b652bc33d52f2322b77463e4dc58abf8 Mon Sep 17 00:00:00 2001 From: Alexander Gordeev Date: Fri, 9 Mar 2012 14:59:26 +0100 Subject: genirq: Get rid of unnecessary irqaction field in task_struct When a new thread handler is created, an irqaction is passed to it as data. Not only that irqaction is stored in task_struct by the handler for later use, but also a structure associated with the kernel thread keeps this value as long as the thread exists. This fix kicks irqaction out off task_struct. Yes, I introduce new bit field. But it allows not only to eliminate the duplicate, but also shortens size of task_struct. Reported-by: Oleg Nesterov Signed-off-by: Alexander Gordeev Link: http://lkml.kernel.org/r/20120309135925.GB2114@dhcp-26-207.brq.redhat.com Signed-off-by: Thomas Gleixner --- kernel/irq/manage.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) (limited to 'kernel/irq/manage.c') diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index c0730ad8a117..0fa3ce998ecb 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -780,7 +780,7 @@ static int irq_thread(void *data) handler_fn = irq_thread_fn; sched_setscheduler(current, SCHED_FIFO, ¶m); - current->irqaction = action; + current->irq_thread = 1; while (!irq_wait_for_interrupt(action)) { @@ -818,10 +818,10 @@ static int irq_thread(void *data) irq_finalize_oneshot(desc, action, true); /* - * Clear irqaction. Otherwise exit_irq_thread() would make + * 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 +832,30 @@ 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. */ - irq_finalize_oneshot(desc, tsk->irqaction, true); + irq_finalize_oneshot(desc, action, true); /* * Set the THREAD DIED flag to prevent further wakeups of the * soon to be gone threaded handler. */ - set_bit(IRQTF_DIED, &tsk->irqaction->flags); + set_bit(IRQTF_DIED, &action->flags); } static void irq_setup_forced_threading(struct irqaction *new) -- cgit v1.2.3 From 05d74efa3c72a5c40b0edeb15856c0230126313b Mon Sep 17 00:00:00 2001 From: Alexander Gordeev Date: Fri, 9 Mar 2012 14:59:40 +0100 Subject: genirq: No need to check IRQTF_DIED before stopping a thread handler Since 63706172f332fd3f6e7458ebfb35fa6de9c21dc5 kthread_stop() is not afraid of dead kernel threads. So no need to check if a thread is alive before stopping it. These checks still were racy. Reported-by: Oleg Nesterov Signed-off-by: Alexander Gordeev Link: http://lkml.kernel.org/r/20120309135939.GC2114@dhcp-26-207.brq.redhat.com Signed-off-by: Thomas Gleixner --- kernel/irq/manage.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'kernel/irq/manage.c') diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 0fa3ce998ecb..3feab4ab6877 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -1106,8 +1106,7 @@ 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: @@ -1217,8 +1216,7 @@ 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); } -- cgit v1.2.3 From 5234ffb9f74cfa8993d174782bc861dd9b7b5bfb Mon Sep 17 00:00:00 2001 From: Alexander Gordeev Date: Fri, 9 Mar 2012 14:59:59 +0100 Subject: genirq: Get rid of unnecessary IRQTF_DIED flag Currently IRQTF_DIED flag is set when a IRQ thread handler calls do_exit() But also PF_EXITING per process flag gets set when a thread exits. This fix eliminates the duplicate by using PF_EXITING flag. Also, there is a race condition in exit_irq_thread(). In case a thread's bit is cleared in desc->threads_oneshot (and the IRQ line gets unmasked), but before IRQTF_DIED flag is set, a new interrupt might come in and set just cleared bit again, this time forever. This fix throws IRQTF_DIED flag away, eliminating the race as a result. [ tglx: Test THREAD_EXITING first as suggested by Oleg ] Reported-by: Oleg Nesterov Signed-off-by: Alexander Gordeev Link: http://lkml.kernel.org/r/20120309135958.GD2114@dhcp-26-207.brq.redhat.com Signed-off-by: Thomas Gleixner --- kernel/irq/manage.c | 11 +---------- 1 file changed, 1 insertion(+), 10 deletions(-) (limited to 'kernel/irq/manage.c') diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 3feab4ab6877..a94466db73b2 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -845,17 +845,8 @@ void exit_irq_thread(void) desc = irq_to_desc(action->irq); - /* - * Prevent a stale desc->threads_oneshot. Must be called - * before setting the IRQTF_DIED flag. - */ + /* Prevent a stale desc->threads_oneshot */ irq_finalize_oneshot(desc, action, true); - - /* - * Set the THREAD DIED flag to prevent further wakeups of the - * soon to be gone threaded handler. - */ - set_bit(IRQTF_DIED, &action->flags); } static void irq_setup_forced_threading(struct irqaction *new) -- cgit v1.2.3 From 7140ea1980f2fae9c7aaeac5f6b35317e1389ee6 Mon Sep 17 00:00:00 2001 From: Ido Yariv Date: Fri, 2 Dec 2011 18:24:12 +0200 Subject: genirq: Flush the irq thread on synchronization The current implementation does not always flush the threaded handler when disabling the irq. In case the irq handler was called, but the threaded handler hasn't started running yet, the interrupt will be flagged as pending, and the handler will not run. This implementation has some issues: First, if the interrupt is a wake source and flagged as pending, the system will not be able to suspend. Second, when quickly disabling and re-enabling the irq, the threaded handler might continue to run after the irq is re-enabled without the irq handler being called first. This might be an unexpected behavior. In addition, it might be counter-intuitive that the threaded handler will not be called even though the irq handler was called and returned IRQ_WAKE_THREAD. Fix this by always waiting for the threaded handler to complete in synchronize_irq(). [ tglx: Massaged comments, added WARN_ONs and the missing IRQTF_RUNTHREAD check in exit_irq_thread() ] Signed-off-by: Ido Yariv Link: http://lkml.kernel.org/r/1322843052-7166-1-git-send-email-ido@wizery.com Signed-off-by: Thomas Gleixner --- kernel/irq/manage.c | 60 ++++++++++++++++++++++++++++------------------------- 1 file changed, 32 insertions(+), 28 deletions(-) (limited to 'kernel/irq/manage.c') diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 1786cf7dac54..453feedbb390 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 */ @@ -771,7 +778,6 @@ 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, &action->thread_flags)) @@ -783,39 +789,30 @@ static int irq_thread(void *data) 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); + /* + * 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 should be set. + * + * Verify that this is true. + */ + if (WARN_ON(test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))) + wake_threads_waitq(desc); + + if (WARN_ON(desc->threads_oneshot & action->thread_mask)) + irq_finalize_oneshot(desc, action, true); /* * Clear irq_thread. Otherwise exit_irq_thread() would make @@ -845,6 +842,13 @@ void exit_irq_thread(void) desc = irq_to_desc(action->irq); + /* + * If IRQTF_RUNTHREAD is set, we need to decrement + * desc->threads_active and wake possible waiters. + */ + if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags)) + wake_threads_waitq(desc); + /* Prevent a stale desc->threads_oneshot */ irq_finalize_oneshot(desc, action, true); } -- cgit v1.2.3 From e04268b0effc0ceea366c50b3107baad9edadafa Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Thu, 15 Mar 2012 22:55:21 +0100 Subject: genirq: Remove paranoid warnons and bogus fixups Alexander pointed out that the warnons in the regular exit path are bogus and the thread_mask one actually could be triggered when __setup_irq() hands out that thread_mask again after __free_irq() dropped irq_desc->lock. Thinking more about it, neither IRQTF_RUNTHREAD nor the bit in thread_mask can be set as this is the regular exit path. We come here due to: __free_irq() remove action from desc synchronize_irq() kthread_stop() So synchronize_irq() makes sure that the thread finished running and cleaned up both the thread_active count and thread_mask. After that point nothing can set IRQTF_RUNTHREAD on this action. So the warnons and the cleanups are pointless. Reported-by: Alexander Gordeev Cc: Ido Yariv Link: http://lkml.kernel.org/r/20120315190755.GA6732@dhcp-26-207.brq.redhat.com Signed-off-by: Thomas Gleixner --- kernel/irq/manage.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-) (limited to 'kernel/irq/manage.c') diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 453feedbb390..b0ccd1ac2d6a 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -804,17 +804,11 @@ static int irq_thread(void *data) * 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 should be set. + * 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. * - * Verify that this is true. - */ - if (WARN_ON(test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))) - wake_threads_waitq(desc); - - if (WARN_ON(desc->threads_oneshot & action->thread_mask)) - irq_finalize_oneshot(desc, action, true); - - /* * Clear irq_thread. Otherwise exit_irq_thread() would make * fuzz about an active irq thread going into nirvana. */ -- cgit v1.2.3 From f3f79e38d51f8a419f4c484a86ece4baea35b993 Mon Sep 17 00:00:00 2001 From: Alexander Gordeev Date: Wed, 21 Mar 2012 17:22:35 +0100 Subject: genirq: Get rid of unneeded force parameter in irq_finalize_oneshot() The only place irq_finalize_oneshot() is called with force parameter set is the threaded handler error exit path. But IRQTF_RUNTHREAD is dropped at this point and irq_wake_thread() is not going to set it again, since PF_EXITING is set for this thread already. So irq_finalize_oneshot() will drop the threads bit in threads_oneshot anyway and hence the force parameter is superfluous. Signed-off-by: Alexander Gordeev Link: http://lkml.kernel.org/r/20120321162234.GP24806@dhcp-26-207.brq.redhat.com Signed-off-by: Thomas Gleixner --- kernel/irq/manage.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'kernel/irq/manage.c') diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index b0ccd1ac2d6a..bf606a53a21c 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -645,7 +645,7 @@ static int irq_wait_for_interrupt(struct irqaction *action) * is marked MASKED. */ static void irq_finalize_oneshot(struct irq_desc *desc, - struct irqaction *action, bool force) + struct irqaction *action) { if (!(desc->istate & IRQS_ONESHOT)) return; @@ -679,7 +679,7 @@ again: * we would clear the threads_oneshot bit of this thread which * was just set. */ - if (!force && test_bit(IRQTF_RUNTHREAD, &action->thread_flags)) + if (test_bit(IRQTF_RUNTHREAD, &action->thread_flags)) goto out_unlock; desc->threads_oneshot &= ~action->thread_mask; @@ -739,7 +739,7 @@ irq_forced_thread_fn(struct irq_desc *desc, struct irqaction *action) local_bh_disable(); ret = action->thread_fn(action->irq, action->dev_id); - irq_finalize_oneshot(desc, action, false); + irq_finalize_oneshot(desc, action); local_bh_enable(); return ret; } @@ -755,7 +755,7 @@ static irqreturn_t irq_thread_fn(struct irq_desc *desc, irqreturn_t ret; ret = action->thread_fn(action->irq, action->dev_id); - irq_finalize_oneshot(desc, action, false); + irq_finalize_oneshot(desc, action); return ret; } @@ -844,7 +844,7 @@ void exit_irq_thread(void) wake_threads_waitq(desc); /* Prevent a stale desc->threads_oneshot */ - irq_finalize_oneshot(desc, action, true); + irq_finalize_oneshot(desc, action); } static void irq_setup_forced_threading(struct irqaction *new) -- cgit v1.2.3 From 241fc640be783f903e74b6d9c68481c01873f758 Mon Sep 17 00:00:00 2001 From: Prarit Bhargava Date: Mon, 26 Mar 2012 15:02:18 -0400 Subject: genirq: Respect NUMA node affinity in setup_irq_irq affinity() We respect node affinity of devices already in the irq descriptor allocation, but we ignore it for the initial interrupt affinity setup, so the interrupt might be routed to a different node. Restrict the default affinity mask to the node on which the irq descriptor is allocated. [ tglx: Massaged changelog ] Signed-off-by: Prarit Bhargava Acked-by: Neil Horman Cc: Yinghai Lu Cc: David Rientjes Link: http://lkml.kernel.org/r/1332788538-17425-1-git-send-email-prarit@redhat.com Signed-off-by: Thomas Gleixner --- kernel/irq/manage.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) (limited to 'kernel/irq/manage.c') diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index bf606a53a21c..89a3ea82569b 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -282,7 +282,7 @@ setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask) { struct irq_chip *chip = irq_desc_get_chip(desc); struct cpumask *set = irq_default_affinity; - int ret; + int ret, node = desc->irq_data.node; /* Excludes PER_CPU and NO_BALANCE interrupts */ if (!irq_can_set_affinity(irq)) @@ -301,6 +301,13 @@ setup_affinity(unsigned int irq, struct irq_desc *desc, struct cpumask *mask) } cpumask_and(mask, cpu_online_mask, set); + if (node != NUMA_NO_NODE) { + const struct cpumask *nodemask = cpumask_of_node(node); + + /* make sure at least one of the cpus in nodemask is online */ + if (cpumask_intersects(mask, nodemask)) + cpumask_and(mask, mask, nodemask); + } ret = chip->irq_set_affinity(&desc->irq_data, mask, false); switch (ret) { case IRQ_SET_MASK_OK: -- cgit v1.2.3