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authorAkinobu Mita <akinobu.mita@gmail.com>2012-07-30 14:40:55 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-07-30 17:25:16 -0700
commit639b9e34f15e4b2c30068a4e4485586af0cdf709 (patch)
treea84e3277a55757dac4630e3d20bc353b195c3c10 /include/linux/string.h
parentf7f95056779eb69c5fc3ac30e5cb6fd28bdbba43 (diff)
string: introduce memweight()
memweight() is the function that counts the total number of bits set in memory area. Unlike bitmap_weight(), memweight() takes pointer and size in bytes to specify a memory area which does not need to be aligned to long-word boundary. [akpm@linux-foundation.org: rename `w' to `ret'] Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Cc: Anders Larsen <al@alarsen.net> Cc: Alasdair Kergon <agk@redhat.com> Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Jan Kara <jack@suse.cz> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Matthew Wilcox <matthew@wil.cx> Cc: Mauro Carvalho Chehab <mchehab@infradead.org> Cc: Tony Luck <tony.luck@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/string.h')
-rw-r--r--include/linux/string.h3
1 files changed, 3 insertions, 0 deletions
diff --git a/include/linux/string.h b/include/linux/string.h
index e033564f10ba..ffe0442e18d2 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -145,4 +145,7 @@ static inline bool strstarts(const char *str, const char *prefix)
return strncmp(str, prefix, strlen(prefix)) == 0;
}
#endif
+
+extern size_t memweight(const void *ptr, size_t bytes);
+
#endif /* _LINUX_STRING_H_ */