lib/bitmap: Introduce bitmap_scatter() and bitmap_gather() helpers
These helpers scatters or gathers a bitmap with the help of the mask
position bits parameter.
bitmap_scatter() does the following:
src:
0000000001011010
||||||
+------+|||||
| +----+||||
| |+----+|||
| || +-+||
| || | ||
mask: ...v..vv...v..vv
...0..11...0..10
dst:
0000001100000010
and bitmap_gather() performs this one:
mask: ...v..vv...v..vv
src:
0000001100000010
^ ^^ ^ 0
| || | 10
| || > 010
| |+--> 1010
| +--> 11010
+----> 011010
dst:
0000000000011010
bitmap_gather() can the seen as the reverse bitmap_scatter() operation.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/lkml/20230926052007.3917389-3-andriy.shevchenko@linux.intel.com/
Co-developed-by: Herve Codina <herve.codina@bootlin.com>
Signed-off-by: Herve Codina <herve.codina@bootlin.com>
Acked-by: Yury Norov <yury.norov@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>