Branch data     Line data    Source code

       1                 :            : #include <linux/export.h>
       2                 :            : #include <linux/bug.h>
       3                 :            : #include <linux/bitmap.h>
       4                 :            : 
       5                 :            : /**
       6                 :            :  * memweight - count the total number of bits set in memory area
       7                 :            :  * @ptr: pointer to the start of the area
       8                 :            :  * @bytes: the size of the area
       9                 :            :  */
      10                 :          0 : size_t memweight(const void *ptr, size_t bytes)
      11                 :            : {
      12                 :            :         size_t ret = 0;
      13                 :            :         size_t longs;
      14                 :            :         const unsigned char *bitmap = ptr;
      15                 :            : 
      16 [ #  # ][ #  # ]:          0 :         for (; bytes > 0 && ((unsigned long)bitmap) % sizeof(long);
      17                 :          0 :                         bytes--, bitmap++)
      18         [ #  # ]:          0 :                 ret += hweight8(*bitmap);
      19                 :            : 
      20                 :          0 :         longs = bytes / sizeof(long);
      21         [ #  # ]:          0 :         if (longs) {
      22         [ #  # ]:          0 :                 BUG_ON(longs >= INT_MAX / BITS_PER_LONG);
      23                 :          0 :                 ret += bitmap_weight((unsigned long *)bitmap,
      24                 :          0 :                                 longs * BITS_PER_LONG);
      25                 :          0 :                 bytes -= longs * sizeof(long);
      26                 :          0 :                 bitmap += longs * sizeof(long);
      27                 :            :         }
      28                 :            :         /*
      29                 :            :          * The reason that this last loop is distinct from the preceding
      30                 :            :          * bitmap_weight() call is to compute 1-bits in the last region smaller
      31                 :            :          * than sizeof(long) properly on big-endian systems.
      32                 :            :          */
      33         [ #  # ]:          0 :         for (; bytes > 0; bytes--, bitmap++)
      34         [ #  # ]:          0 :                 ret += hweight8(*bitmap);
      35                 :            : 
      36                 :          0 :         return ret;
      37                 :            : }
      38                 :            : EXPORT_SYMBOL(memweight);