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lib: add bitmap_{from,to}_arr64

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Manipulating 64-bit arrays with bitmap functions is potentially dangerous
because on 32-bit BE machines the order of halfwords doesn't match.
Another issue is that compiler may throw a warning about out-of-boundary
access.

This patch adds bitmap_{from,to}_arr64 functions in addition to existing
bitmap_{from,to}_arr32.

CC: Alexander Gordeev <agordeev@linux.ibm.com>
CC: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
CC: Christian Borntraeger <borntraeger@linux.ibm.com>
CC: Claudio Imbrenda <imbrenda@linux.ibm.com>
CC: David Hildenbrand <david@redhat.com>
CC: Heiko Carstens <hca@linux.ibm.com>
CC: Janosch Frank <frankja@linux.ibm.com>
CC: Rasmus Villemoes <linux@rasmusvillemoes.dk>
CC: Sven Schnelle <svens@linux.ibm.com>
CC: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Yury Norov <yury.norov@gmail.com>
This commit is contained in:
Yury Norov 2022-04-28 13:51:13 -07:00
parent e041e0ac53
commit 0a97953fd2
2 changed files with 74 additions and 5 deletions
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23
include/linux/bitmap.h
View file

@ -72,6 +72,8 @@ struct device;
* bitmap_allocate_region(bitmap, pos, order) Allocate specified bit region
* bitmap_from_arr32(dst, buf, nbits) Copy nbits from u32[] buf to dst
* bitmap_to_arr32(buf, src, nbits) Copy nbits from buf to u32[] dst
* bitmap_to_arr64(buf, src, nbits) Copy nbits from buf to u64[] dst
* bitmap_to_arr64(buf, src, nbits) Copy nbits from buf to u64[] dst
* bitmap_get_value8(map, start) Get 8bit value from map at start
* bitmap_set_value8(map, value, start) Set 8bit value to map at start
*
@ -285,6 +287,22 @@ void bitmap_to_arr32(u32 *buf, const unsigned long *bitmap,
(const unsigned long *) (bitmap), (nbits))
#endif
/*
* On 64-bit systems bitmaps are represented as u64 arrays internally. On LE32
* machines the order of hi and lo parts of numbers match the bitmap structure.
* In both cases conversion is not needed when copying data from/to arrays of
* u64.
*/
#if (BITS_PER_LONG == 32) && defined(__BIG_ENDIAN)
void bitmap_from_arr64(unsigned long *bitmap, const u64 *buf, unsigned int nbits);
void bitmap_to_arr64(u64 *buf, const unsigned long *bitmap, unsigned int nbits);
#else
#define bitmap_from_arr64(bitmap, buf, nbits) \
bitmap_copy_clear_tail((unsigned long *)(bitmap), (const unsigned long *)(buf), (nbits))
#define bitmap_to_arr64(buf, bitmap, nbits) \
bitmap_copy_clear_tail((unsigned long *)(buf), (const unsigned long *)(bitmap), (nbits))
#endif
static inline int bitmap_and(unsigned long *dst, const unsigned long *src1,
const unsigned long *src2, unsigned int nbits)
{
@ -518,10 +536,7 @@ static inline void bitmap_next_set_region(unsigned long *bitmap,
*/
static inline void bitmap_from_u64(unsigned long *dst, u64 mask)
{
dst[0] = mask & ULONG_MAX;
if (sizeof(mask) > sizeof(unsigned long))
dst[1] = mask >> 32;
bitmap_from_arr64(dst, &mask, 64);
}
/**