linux-kernel - [PATCH 2/3] drm/i915: work around false-positive maybe-uninitialized warning

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Message-Id: <20200527140526.1458215-2-arnd@arndb.de>
Date:   Wed, 27 May 2020 16:05:09 +0200
From:   Arnd Bergmann <arnd@...db.de>
To:     Jani Nikula <jani.nikula@...ux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@...el.com>,
        David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Tvrtko Ursulin <tvrtko.ursulin@...el.com>,
        John Harrison <John.C.Harrison@...el.com>
Cc:     Arnd Bergmann <arnd@...db.de>,
        Chris Wilson <chris@...is-wilson.co.uk>,
        Matthew Auld <matthew.auld@...el.com>,
        Mika Kuoppala <mika.kuoppala@...ux.intel.com>,
        Daniele Ceraolo Spurio <daniele.ceraolospurio@...el.com>,
        Lionel Landwerlin <lionel.g.landwerlin@...el.com>,
        "Robert M. Fosha" <robert.m.fosha@...el.com>,
        intel-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org
Subject: [PATCH 2/3] drm/i915: work around false-positive maybe-uninitialized warning

gcc-9 gets confused by the code flow in check_dirty_whitelist:

drivers/gpu/drm/i915/gt/selftest_workarounds.c: In function 'check_dirty_whitelist':
drivers/gpu/drm/i915/gt/selftest_workarounds.c:492:17: error: 'rsvd' may be used uninitialized in this function [-Werror=maybe-uninitialized]

I could not figure out a good way to do this in a way that gcc
understands better, so initialize the variable to zero, as last
resort.

Fixes: aee20aaed887 ("drm/i915: Implement read-only support in whitelist selftest")
Signed-off-by: Arnd Bergmann <arnd@...db.de>
---
 drivers/gpu/drm/i915/gt/selftest_workarounds.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/i915/gt/selftest_workarounds.c b/drivers/gpu/drm/i915/gt/selftest_workarounds.c
index 5ed323254ee1..32785463ec9e 100644
--- a/drivers/gpu/drm/i915/gt/selftest_workarounds.c
+++ b/drivers/gpu/drm/i915/gt/selftest_workarounds.c
@@ -623,6 +623,8 @@ static int check_dirty_whitelist(struct intel_context *ce)
 				err = -EINVAL;
 				goto out_unpin;
 			}
+		} else {
+			rsvd = 0;
 		}
 
 		expect = results[0];
-- 
2.26.2