#include <linux/export.h>
#include <linux/bug.h>
#include <linux/errno.h>
+#include <linux/bitmap.h>
#ifndef __HAVE_ARCH_STRNICMP
/**
return check_bytes8(start, value, bytes % 8);
}
EXPORT_SYMBOL(memchr_inv);
+
+/**
+ * memweight - count the total number of bits set in memory area
+ * @ptr: pointer to the start of the area
+ * @bytes: the size of the area
+ */
+size_t memweight(const void *ptr, size_t bytes)
+{
+ size_t w = 0;
+ size_t longs;
+ const unsigned char *bitmap = ptr;
+
+ for (; bytes > 0 && ((unsigned long)bitmap) % sizeof(long);
+ bytes--, bitmap++)
+ w += hweight8(*bitmap);
+
+ longs = bytes / sizeof(long);
+ if (longs) {
+ BUG_ON(longs >= INT_MAX / BITS_PER_LONG);
+ w += bitmap_weight((unsigned long *)bitmap,
+ longs * BITS_PER_LONG);
+ bytes -= longs * sizeof(long);
+ bitmap += longs * sizeof(long);
+ }
+ /*
+ * The reason that this last loop is distinct from the preceding
+ * bitmap_weight() call is to compute 1-bits in the last region smaller
+ * than sizeof(long) properly on big-endian systems.
+ */
+ for (; bytes > 0; bytes--, bitmap++)
+ w += hweight8(*bitmap);
+
+ return w;
+}
+EXPORT_SYMBOL(memweight);