genirq: Fix misleading synchronize_irq() documentation

BugLink: https://bugs.launchpad.net/bugs/1839036
commit 1d21f2af8571c6a6a44e7c1911780614847b0253 upstream

The function might sleep, so it cannot be called from interrupt
context. Not even with care.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Link: https://lkml.kernel.org/r/20190628111440.189241552@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 609376da23349a733b7308cad528fd7df5aa5430..56b11ae9aaece015a328397a1e969c5216a5a708 100644 (file)
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -102,7 +102,8 @@ EXPORT_SYMBOL(synchronize_hardirq);
  *     to complete before returning. If you use this function while
  *     holding a resource the IRQ handler may need you will deadlock.
  *
- *     This function may be called - with care - from IRQ context.
+ *     Can only be called from preemptible code as it might sleep when
+ *     an interrupt thread is associated to @irq.
  */
 void synchronize_irq(unsigned int irq)
 {