Revision 15c206887603a452f13fbfde2db0f8830d37028c authored by Jens Axboe on 28 September 2018, 15:40:17 UTC, committed by Jens Axboe on 28 September 2018, 15:40:17 UTC
Fix didn't work for all cases, reverting to add a (hopefully) better fix. This reverts commit f151ba989d149bbdfc90e5405724bbea094f9b17. Signed-off-by: Jens Axboe <axboe@kernel.dk>
1 parent 587562d
memweight.c
// SPDX-License-Identifier: GPL-2.0
#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);
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