| // SPDX-License-Identifier: GPL-2.0 |
| #include <linux/export.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) |
| const unsigned char *bitmap = ptr; |
| for (; bytes > 0 && ((unsigned long)bitmap) % sizeof(long); |
| ret += hweight8(*bitmap); |
| longs = bytes / sizeof(long); |
| BUG_ON(longs >= INT_MAX / BITS_PER_LONG); |
| ret += bitmap_weight((unsigned long *)bitmap, |
| 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); |
| EXPORT_SYMBOL(memweight); |