[tip:irq/urgent] irqchip/gic-v3-its: Silence warning when its_lpi_alloc_chunks gets inlined

[tip-bot for Marc Zyngier <tipbot@zytor.com>]

Commit-ID:  c8415b9470727f70afce8607d4fe521789aa6c1c
Gitweb:     http://git.kernel.org/tip/c8415b9470727f70afce8607d4fe521789aa6c1c
Author:     Marc Zyngier <marc.zyngier@arm.com>
AuthorDate: Fri, 2 Oct 2015 16:44:05 +0100
Committer:  Thomas Gleixner <tglx@linutronix.de>
CommitDate: Fri, 2 Oct 2015 20:51:41 +0200

irqchip/gic-v3-its: Silence warning when its_lpi_alloc_chunks gets inlined

More agressive inlining in recent versions of GCC have uncovered
a new set of warnings:

 drivers/irqchip/irq-gic-v3-its.c: In function its_msi_prepare:
  drivers/irqchip/irq-gic-v3-its.c:1148:26: warning: lpi_base may be used
    uninitialized in this function [-Wmaybe-uninitialized]
     dev->event_map.lpi_base = lpi_base;
                          ^
 drivers/irqchip/irq-gic-v3-its.c:1116:6: note: lpi_base was declared here
  int lpi_base;
	      ^
 drivers/irqchip/irq-gic-v3-its.c:1149:25: warning: nr_lpis may be used
  uninitialized in this function [-Wmaybe-uninitialized]
   dev->event_map.nr_lpis = nr_lpis;
	                         ^
 drivers/irqchip/irq-gic-v3-its.c:1117:6: note: nr_lpis was declared here
  int nr_lpis;
	      ^
The warning is fairly benign (there is no code path that could
actually use uninitialized variables), but let's silence it anyway
by zeroing the variables on the error path.

Reported-by: Alex Shi <alex.shi@linaro.org>
Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Cc: linux-arm-kernel@lists.infradead.org
Cc: David Daney <ddaney.cavm@gmail.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Link: http://lkml.kernel.org/r/1443800646-8074-2-git-send-email-marc.zyngier@arm.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 drivers/irqchip/irq-gic-v3-its.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c
index ac7ae2b..25ceae9f 100644
--- a/drivers/irqchip/irq-gic-v3-its.c
+++ b/drivers/irqchip/irq-gic-v3-its.c
@@ -719,6 +719,9 @@ static unsigned long *its_lpi_alloc_chunks(int nr_irqs, int *base, int *nr_ids)
 out:
 	spin_unlock(&lpi_lock);
 
+	if (!bitmap)
+		*base = *nr_ids = 0;
+
 	return bitmap;
 }