__bitmap_shift_right — logical right shift of the bits in a bitmap
void __bitmap_shift_right
(unsigned long * dst, const unsigned long * src, int shift, int bits);
destination bitmap
source bitmap
shift by this many bits
bitmap size, in bits
Shifting right (dividing) means moving bits in the MS -> LS bit direction. Zeros are fed into the vacated MS positions and the LS bits shifted off the bottom are lost.