linux-kernel - [PATCH 4.7 149/184] genirq: Provide irq_gc_{lock_irqsave,unlock

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Message-Id: <20160922174055.101101649@linuxfoundation.org>
Date:   Thu, 22 Sep 2016 19:41:23 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        Boris Brezillon <boris.brezillon@...e-electrons.com>,
        Jason Cooper <jason@...edaemon.net>,
        Marc Zyngier <marc.zyngier@....com>,
        Nicolas Ferre <nicolas.ferre@...el.com>,
        Alexandre Belloni <alexandre.belloni@...e-electrons.com>,
        Thomas Gleixner <tglx@...utronix.de>
Subject: [PATCH 4.7 149/184] genirq: Provide irq_gc_{lock_irqsave,unlock_irqrestore}() helpers

4.7-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Boris Brezillon <boris.brezillon@...e-electrons.com>

commit ebf9ff753c041b296241990aef76163bbb2cc9c8 upstream.

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@...e-electrons.com>
Cc: Jason Cooper <jason@...edaemon.net>
Cc: Marc Zyngier <marc.zyngier@....com>
Cc: Nicolas Ferre <nicolas.ferre@...el.com>
Cc: Alexandre Belloni <alexandre.belloni@...e-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@...utronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

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

--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -933,6 +933,16 @@ static inline void irq_gc_lock(struct ir
 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)
 {