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author | Thomas Gleixner <tglx@linutronix.de> | 2012-03-13 19:34:48 +0400 |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2012-03-13 19:35:16 +0400 |
commit | df8d291f28aa1e8437c8f7816328a6516379c71b (patch) | |
tree | 26ae585aa259584ddd0d9088933547c065c37086 /kernel/irq/manage.c | |
parent | 5234ffb9f74cfa8993d174782bc861dd9b7b5bfb (diff) | |
parent | fde7d9049e55ab85a390be7f415d74c9f62dd0f9 (diff) | |
download | linux-df8d291f28aa1e8437c8f7816328a6516379c71b.tar.xz |
Merge branch 'linus' into irq/core
Reason: Get upstream fixes integrated before further modifications.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/irq/manage.c')
-rw-r--r-- | kernel/irq/manage.c | 46 |
1 files changed, 39 insertions, 7 deletions
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index a94466db73b2..1786cf7dac54 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -979,6 +979,11 @@ __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; @@ -987,14 +992,41 @@ __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); @@ -1021,7 +1053,7 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) desc->istate |= IRQS_ONESHOT; if (irq_settings_can_autoenable(desc)) - irq_startup(desc); + irq_startup(desc, true); else /* Undo nested disables: */ desc->depth = 1; |