include/linux/adfs_fs.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ADFS_FS_H
   3 #define _ADFS_FS_H
   4
   5 #include <uapi/linux/adfs_fs.h>
   6
   7 /*
   8  * Calculate the boot block checksum on an ADFS drive.  Note that this will
   9  * appear to be correct if the sector contains all zeros, so also check that
  10  * the disk size is non-zero!!!
  11  */
  12 static inline int adfs_checkbblk(unsigned char *ptr)
  13 {
  14         unsigned int result = 0;
  15         unsigned char *p = ptr + 511;
  16
  17         do {
  18                 result = (result & 0xff) + (result >> 8);
  19                 result = result + *--p;
  20         } while (p != ptr);
  21
  22         return (result & 0xff) != ptr[511];
  23 }
  24 #endif