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-rw-r--r--include/linux/adfs_fs.h23
1 files changed, 23 insertions, 0 deletions
diff --git a/include/linux/adfs_fs.h b/include/linux/adfs_fs.h
new file mode 100644
index 000000000..0d991071a
--- /dev/null
+++ b/include/linux/adfs_fs.h
@@ -0,0 +1,23 @@
+#ifndef _ADFS_FS_H
+#define _ADFS_FS_H
+
+#include <uapi/linux/adfs_fs.h>
+
+/*
+ * Calculate the boot block checksum on an ADFS drive. Note that this will
+ * appear to be correct if the sector contains all zeros, so also check that
+ * the disk size is non-zero!!!
+ */
+static inline int adfs_checkbblk(unsigned char *ptr)
+{
+ unsigned int result = 0;
+ unsigned char *p = ptr + 511;
+
+ do {
+ result = (result & 0xff) + (result >> 8);
+ result = result + *--p;
+ } while (p != ptr);
+
+ return (result & 0xff) != ptr[511];
+}
+#endif