* [PATCH] mm/sparse: fix a bad comparison
@ 2019-02-28 18:18 Qian Cai
0 siblings, 0 replies; only message in thread
From: Qian Cai @ 2019-02-28 18:18 UTC (permalink / raw)
To: akpm; +Cc: dave.hansen, linux-mm, linux-kernel, Qian Cai
next_present_section_nr() could only return an unsigned number -1, so
just check it specifically where compilers will convert -1 to unsigned
if needed.
mm/sparse.c: In function 'sparse_init_nid':
mm/sparse.c:200:20: warning: comparison of unsigned expression >= 0 is
always true [-Wtype-limits]
((section_nr >= 0) && \
^~
mm/sparse.c:478:2: note: in expansion of macro
'for_each_present_section_nr'
for_each_present_section_nr(pnum_begin, pnum) {
^~~~~~~~~~~~~~~~~~~~~~~~~~~
mm/sparse.c:200:20: warning: comparison of unsigned expression >= 0 is
always true [-Wtype-limits]
((section_nr >= 0) && \
^~
mm/sparse.c:497:2: note: in expansion of macro
'for_each_present_section_nr'
for_each_present_section_nr(pnum_begin, pnum) {
^~~~~~~~~~~~~~~~~~~~~~~~~~~
mm/sparse.c: In function 'sparse_init':
mm/sparse.c:200:20: warning: comparison of unsigned expression >= 0 is
always true [-Wtype-limits]
((section_nr >= 0) && \
^~
mm/sparse.c:520:2: note: in expansion of macro
'for_each_present_section_nr'
for_each_present_section_nr(pnum_begin + 1, pnum_end) {
^~~~~~~~~~~~~~~~~~~~~~~~~~~
Fixes: c4e1be9ec113 ("mm, sparsemem: break out of loops early")
Signed-off-by: Qian Cai <cai@lca.pw>
---
mm/sparse.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/sparse.c b/mm/sparse.c
index 7ea5dc6c6b19..77a0554fa5bd 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -197,7 +197,7 @@ static inline int next_present_section_nr(int section_nr)
}
#define for_each_present_section_nr(start, section_nr) \
for (section_nr = next_present_section_nr(start-1); \
- ((section_nr >= 0) && \
+ ((section_nr != -1) && \
(section_nr <= __highest_present_section_nr)); \
section_nr = next_present_section_nr(section_nr))
--
2.17.2 (Apple Git-113)
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