diff options
author | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-08-06 09:48:31 -0700 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2012-08-06 09:48:31 -0700 |
commit | c87985a3ce723995fc7b25e598238d67154108a1 (patch) | |
tree | e60def1b77c25c1d74180f62e8a5603f9826f209 /lib/memweight.c | |
parent | d155255a344c417acad74156654295a2964e6b81 (diff) | |
parent | 0d7614f09c1ebdbaa1599a5aba7593f147bf96ee (diff) |
Merge tty-next into 3.6-rc1
This handles the merge issue in:
arch/um/drivers/line.c
arch/um/drivers/line.h
And resolves the duplicate patches that were in both trees do to the
tty-next branch not getting merged into 3.6-rc1.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'lib/memweight.c')
-rw-r--r-- | lib/memweight.c | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/lib/memweight.c b/lib/memweight.c new file mode 100644 index 00000000000..e35fc877189 --- /dev/null +++ b/lib/memweight.c @@ -0,0 +1,38 @@ +#include <linux/export.h> +#include <linux/bug.h> +#include <linux/bitmap.h> + +/** + * memweight - count the total number of bits set in memory area + * @ptr: pointer to the start of the area + * @bytes: the size of the area + */ +size_t memweight(const void *ptr, size_t bytes) +{ + size_t ret = 0; + size_t longs; + const unsigned char *bitmap = ptr; + + for (; bytes > 0 && ((unsigned long)bitmap) % sizeof(long); + bytes--, bitmap++) + ret += hweight8(*bitmap); + + longs = bytes / sizeof(long); + if (longs) { + BUG_ON(longs >= INT_MAX / BITS_PER_LONG); + ret += bitmap_weight((unsigned long *)bitmap, + longs * BITS_PER_LONG); + bytes -= longs * sizeof(long); + bitmap += longs * sizeof(long); + } + /* + * The reason that this last loop is distinct from the preceding + * bitmap_weight() call is to compute 1-bits in the last region smaller + * than sizeof(long) properly on big-endian systems. + */ + for (; bytes > 0; bytes--, bitmap++) + ret += hweight8(*bitmap); + + return ret; +} +EXPORT_SYMBOL(memweight); |