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authorYang Shi <yang.shi@linaro.org>2015-11-20 15:57:10 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-11-20 16:17:32 -0800
commit50e55bf626ad3ebbca45c0c0d03eb1710a139638 (patch)
treec5ec9ea7b3b7c16e9ddf6af986e095c2b5bb5e8e
parent1a47de6e4a8dc2aaf3c3fb544b60730b74abe0f1 (diff)
mm/page-writeback.c: initialize m_dirty to avoid compile warning
When building kernel with gcc 5.2, the below warning is raised: mm/page-writeback.c: In function 'balance_dirty_pages.isra.10': mm/page-writeback.c:1545:17: warning: 'm_dirty' may be used uninitialized in this function [-Wmaybe-uninitialized] unsigned long m_dirty, m_thresh, m_bg_thresh; The m_dirty{thresh, bg_thresh} are initialized in the block of "if (mdtc)", so if mdts is null, they won't be initialized before being used. Initialize m_dirty to zero, also initialize m_thresh and m_bg_thresh to keep consistency. They are used later by if condition: !mdtc || m_dirty <= dirty_freerun_ceiling(m_thresh, m_bg_thresh) If mdtc is null, dirty_freerun_ceiling will not be called at all, so the initialization will not change any behavior other than just ceasing the compile warning. (akpm: the patch actually reduces .text size by ~20 bytes on gcc-4.x.y) [akpm@linux-foundation.org: add comment] Signed-off-by: Yang Shi <yang.shi@linaro.org> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/page-writeback.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 2c90357c34ea..3e4d65445fa7 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1542,7 +1542,9 @@ static void balance_dirty_pages(struct address_space *mapping,
for (;;) {
unsigned long now = jiffies;
unsigned long dirty, thresh, bg_thresh;
- unsigned long m_dirty, m_thresh, m_bg_thresh;
+ unsigned long m_dirty = 0; /* stop bogus uninit warnings */
+ unsigned long m_thresh = 0;
+ unsigned long m_bg_thresh = 0;
/*
* Unstable writes are a feature of certain networked