genirq: Delegate irq affinity setting to the irq thread
irq_set_thread_affinity() calls set_cpus_allowed_ptr() which might
sleep, but irq_set_thread_affinity() is called with desc->lock held
and can be called from hard interrupt context as well. The code has
another bug as it does not hold a ref on the task struct as required
by set_cpus_allowed_ptr().
Just set the IRQTF_AFFINITY bit in action->thread_flags. The next time
the thread runs it migrates itself. Solves all of the above problems
nicely.
Add kerneldoc to irq_set_thread_affinity() while at it.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <new-submission>
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 2721f07..88b056a 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -64,11 +64,13 @@
* 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
*/
enum {
IRQTF_RUNTHREAD,
IRQTF_DIED,
IRQTF_WARNED,
+ IRQTF_AFFINITY,
};
typedef irqreturn_t (*irq_handler_t)(int, void *);