The __alloc_pages_slowpath() has gotten rather complex and gcc
is no longer able to follow the gotos and prove that the
alloc_flags variable is initialized at the time it is used:
mm/page_alloc.c: In function '__alloc_pages_slowpath':
mm/page_alloc.c:3565:15: error: 'alloc_flags' may be used uninitialized in this function [-Werror=maybe-uninitialized]
To be honest, I can't figure that out either, maybe it is or
maybe not, but moving the existing initialization up a little
higher looks safe and makes it obvious to both me and gcc that
the initialization comes before the first use.
Fixes: 74eaa4a97e8e ("mm: consolidate GFP_NOFAIL checks in the allocator slowpath")
Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
---
mm/page_alloc.c | 15 +++++++--------
1 file changed, 7 insertions(+), 8 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index cf641932c015..d9fa4564524f 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -3591,6 +3591,13 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
(__GFP_ATOMIC|__GFP_DIRECT_RECLAIM)))
gfp_mask &= ~__GFP_ATOMIC;
+ /*
+ * The fast path uses conservative alloc_flags to succeed only until
+ * kswapd needs to be woken up, and to avoid the cost of setting up
+ * alloc_flags precisely. So we do that now.
+ */
+ alloc_flags = gfp_to_alloc_flags(gfp_mask);
+
retry_cpuset:
compaction_retries = 0;
no_progress_loops = 0;
@@ -3607,14 +3614,6 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order,
if (!ac->preferred_zoneref->zone)
goto nopage;
-
- /*
- * The fast path uses conservative alloc_flags to succeed only until
- * kswapd needs to be woken up, and to avoid the cost of setting up
- * alloc_flags precisely. So we do that now.
- */
- alloc_flags = gfp_to_alloc_flags(gfp_mask);
-
if (gfp_mask & __GFP_KSWAPD_RECLAIM)
wake_all_kswapds(order, ac);
--
2.9.0
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