[tip:irq/urgent] genirq: Provide irq_gc_{lock_irqsave,unlock_irqrestore}() helpers

[tip-bot for Boris Brezillon <tipbot@zytor.com>]

Commit-ID:  ebf9ff753c041b296241990aef76163bbb2cc9c8
Gitweb:     http://git.kernel.org/tip/ebf9ff753c041b296241990aef76163bbb2cc9c8
Author:     Boris Brezillon <boris.brezillon@free-electrons.com>
AuthorDate: Tue, 13 Sep 2016 15:58:28 +0200
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Tue, 13 Sep 2016 16:57:40 +0200

genirq: Provide irq_gc_{lock_irqsave,unlock_irqrestore}() helpers

Some irqchip drivers need to take the generic chip lock outside of the
irq context.

Provide the irq_gc_{lock_irqsave,unlock_irqrestore}() helpers to allow
one to disable irqs while entering a critical section protected by
gc->lock.

Note that we do not provide optimized version of these helpers for !SMP,
because they are not called from the hot-path.

[ tglx: Added a comment when these helpers should be [not] used ]

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: stable@vger.kernel.org
Cc: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Link: http://lkml.kernel.org/r/1473775109-4192-1-git-send-email-boris.brezillon@free-electrons.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

---
 include/linux/irq.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/include/linux/irq.h b/include/linux/irq.h
index b52424e..0ac26c8 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -945,6 +945,16 @@ static inline void irq_gc_lock(struct irq_chip_generic *gc) { }
 static inline void irq_gc_unlock(struct irq_chip_generic *gc) { }
 #endif
 
+/*
+ * The irqsave variants are for usage in non interrupt code. Do not use
+ * them in irq_chip callbacks. Use irq_gc_lock() instead.
+ */
+#define irq_gc_lock_irqsave(gc, flags)	\
+	raw_spin_lock_irqsave(&(gc)->lock, flags)
+
+#define irq_gc_unlock_irqrestore(gc, flags)	\
+	raw_spin_unlock_irqrestore(&(gc)->lock, flags)
+
 static inline void irq_reg_writel(struct irq_chip_generic *gc,
 				  u32 val, int reg_offset)
 {