4.19-stable review patch. If anyone has any objections, please let me know.
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[ Upstream commit d778015ac95bc036af73342c878ab19250e01fe1 ]
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) { ^~~~~~~~~~~~~~~~~~~~~~~~~~~
Link: http://lkml.kernel.org/r/20190228181839.86504-1-cai@lca.pw Fixes: c4e1be9ec113 ("mm, sparsemem: break out of loops early") Signed-off-by: Qian Cai cai@lca.pw Reviewed-by: Andrew Morton akpm@linux-foundation.org Cc: Dave Hansen dave.hansen@linux.intel.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- mm/sparse.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/sparse.c b/mm/sparse.c index 10b07eea9a6e..45950a074bdb 100644 --- a/mm/sparse.c +++ b/mm/sparse.c @@ -196,7 +196,7 @@ 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))