Re: [PATCH v2] drm/i915: Initialise entry in intel_ppat_get() for older compilers

["Wang, Zhi A" <zhi.a.wang@intel.com>]

Thanks! Looks good to me.

-----Original Message-----
From: Chris Wilson [mailto:chris@chris-wilson.co.uk] 
Sent: Wednesday, November 15, 2017 3:17 PM
To: intel-gfx@lists.freedesktop.org
Cc: Chris Wilson <chris@chris-wilson.co.uk>; Joonas Lahtinen <joonas.lahtinen@linux.intel.com>; Wang, Zhi A <zhi.a.wang@intel.com>; Ville Syrjälä <ville.syrjala@linux.intel.com>
Subject: [PATCH v2] drm/i915: Initialise entry in intel_ppat_get() for older compilers

gcc-4.7.3 is confused by the guards inside intel_ppat_get() and reports:

drivers/gpu/drm/i915/i915_gem_gtt.c: In function ‘intel_ppat_get’:
drivers/gpu/drm/i915/i915_gem_gtt.c:3044:27: warning: ‘entry’ may be used uninitialized in this function [-Wmaybe-uninitialized]

Forgive the compiler this once, and rearrange the code so that entry is always initialised.

v2: Flavour with a bit of NULL (instead of ERR_PTR(-ENOSPC).

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Zhi Wang <zhi.a.wang@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
---
 drivers/gpu/drm/i915/i915_gem_gtt.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
index 3c3a699436c9..f92a39fc511c 100644
--- a/drivers/gpu/drm/i915/i915_gem_gtt.c
+++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
@@ -3076,7 +3076,7 @@ const struct intel_ppat_entry *  intel_ppat_get(struct drm_i915_private *i915, u8 value)  {
 	struct intel_ppat *ppat = &i915->ppat;
-	struct intel_ppat_entry *entry;
+	struct intel_ppat_entry *entry = NULL;
 	unsigned int scanned, best_score;
 	int i;
 
@@ -3099,7 +3099,7 @@ intel_ppat_get(struct drm_i915_private *i915, u8 value)
 	}
 
 	if (scanned == ppat->max_entries) {
-		if (!best_score)
+		if (!entry)
 			return ERR_PTR(-ENOSPC);
 
 		kref_get(&entry->ref);
--
2.15.0

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