Merge with /pub/scm/linux/kernel/git/torvalds/linux-2.6.git

Signed-off-by: Steve French <sfrench@us.ibm.com>

1 files changed, 150 insertions, 27 deletions

diff --git a/lib/find_next_bit.c b/lib/find_next_bit.c
index c05b4b19cf6c..bda0d71a2514 100644
--- a/lib/find_next_bit.c
+++ b/lib/find_next_bit.c
@@ -11,48 +11,171 @@
 
 #include <linux/bitops.h>
 #include <linux/module.h>
+#include <asm/types.h>
+#include <asm/byteorder.h>
 
-int find_next_bit(const unsigned long *addr, int size, int offset)
+#define BITOP_WORD(nr)          ((nr) / BITS_PER_LONG)
+
+/**
+ * find_next_bit - find the next set bit in a memory region
+ * @addr: The address to base the search on
+ * @offset: The bitnumber to start searching at
+ * @size: The maximum size to search
+ */
+unsigned long find_next_bit(const unsigned long *addr, unsigned long size,
+                unsigned long offset)
 {
-        const unsigned long *base;
-        const int NBITS = sizeof(*addr) * 8;
+        const unsigned long *p = addr + BITOP_WORD(offset);
+        unsigned long result = offset & ~(BITS_PER_LONG-1);
         unsigned long tmp;
 
-        base = addr;
+        if (offset >= size)
+                return size;
+        size -= result;
+        offset %= BITS_PER_LONG;
         if (offset) {
-                int suboffset;
+                tmp = *(p++);
+                tmp &= (~0UL << offset);
+                if (size < BITS_PER_LONG)
+                        goto found_first;
+                if (tmp)
+                        goto found_middle;
+                size -= BITS_PER_LONG;
+                result += BITS_PER_LONG;
+        }
+        while (size & ~(BITS_PER_LONG-1)) {
+                if ((tmp = *(p++)))
+                        goto found_middle;
+                result += BITS_PER_LONG;
+                size -= BITS_PER_LONG;
+        }
+        if (!size)
+                return result;
+        tmp = *p;
 
-                addr += offset / NBITS;
+found_first:
+        tmp &= (~0UL >> (BITS_PER_LONG - size));
+        if (tmp == 0UL)         /* Are any bits set? */
+                return result + size;   /* Nope. */
+found_middle:
+        return result + __ffs(tmp);
+}
 
-                suboffset = offset % NBITS;
-                if (suboffset) {
-                        tmp = *addr;
-                        tmp >>= suboffset;
-                        if (tmp)
-                                goto finish;
-                }
+EXPORT_SYMBOL(find_next_bit);
 
-                addr++;
+/*
+ * This implementation of find_{first,next}_zero_bit was stolen from
+ * Linus' asm-alpha/bitops.h.
+ */
+unsigned long find_next_zero_bit(const unsigned long *addr, unsigned long size,
+                unsigned long offset)
+{
+        const unsigned long *p = addr + BITOP_WORD(offset);
+        unsigned long result = offset & ~(BITS_PER_LONG-1);
+        unsigned long tmp;
+
+        if (offset >= size)
+                return size;
+        size -= result;
+        offset %= BITS_PER_LONG;
+        if (offset) {
+                tmp = *(p++);
+                tmp |= ~0UL >> (BITS_PER_LONG - offset);
+                if (size < BITS_PER_LONG)
+                        goto found_first;
+                if (~tmp)
+                        goto found_middle;
+                size -= BITS_PER_LONG;
+                result += BITS_PER_LONG;
+        }
+        while (size & ~(BITS_PER_LONG-1)) {
+                if (~(tmp = *(p++)))
+                        goto found_middle;
+                result += BITS_PER_LONG;
+                size -= BITS_PER_LONG;
         }
+        if (!size)
+                return result;
+        tmp = *p;
+
+found_first:
+        tmp |= ~0UL << size;
+        if (tmp == ~0UL)        /* Are any bits zero? */
+                return result + size;   /* Nope. */
+found_middle:
+        return result + ffz(tmp);
+}
+
+EXPORT_SYMBOL(find_next_zero_bit);
 
-        while ((tmp = *addr) == 0)
-                addr++;
+#ifdef __BIG_ENDIAN
 
-        offset = (addr - base) * NBITS;
+/* include/linux/byteorder does not support "unsigned long" type */
+static inline unsigned long ext2_swabp(const unsigned long * x)
+{
+#if BITS_PER_LONG == 64
+        return (unsigned long) __swab64p((u64 *) x);
+#elif BITS_PER_LONG == 32
+        return (unsigned long) __swab32p((u32 *) x);
+#else
+#error BITS_PER_LONG not defined
+#endif
+}
+
+/* include/linux/byteorder doesn't support "unsigned long" type */
+static inline unsigned long ext2_swab(const unsigned long y)
+{
+#if BITS_PER_LONG == 64
+        return (unsigned long) __swab64((u64) y);
+#elif BITS_PER_LONG == 32
+        return (unsigned long) __swab32((u32) y);
+#else
+#error BITS_PER_LONG not defined
+#endif
+}
 
- finish:
-        /* count the remaining bits without using __ffs() since that takes a 32-bit arg */
-        while (!(tmp & 0xff)) {
-                offset += 8;
-                tmp >>= 8;
+unsigned long generic_find_next_zero_le_bit(const unsigned long *addr, unsigned
+                long size, unsigned long offset)
+{
+        const unsigned long *p = addr + BITOP_WORD(offset);
+        unsigned long result = offset & ~(BITS_PER_LONG - 1);
+        unsigned long tmp;
+
+        if (offset >= size)
+                return size;
+        size -= result;
+        offset &= (BITS_PER_LONG - 1UL);
+        if (offset) {
+                tmp = ext2_swabp(p++);
+                tmp |= (~0UL >> (BITS_PER_LONG - offset));
+                if (size < BITS_PER_LONG)
+                        goto found_first;
+                if (~tmp)
+                        goto found_middle;
+                size -= BITS_PER_LONG;
+                result += BITS_PER_LONG;
         }
 
-        while (!(tmp & 1)) {
-                offset++;
-                tmp >>= 1;
+        while (size & ~(BITS_PER_LONG - 1)) {
+                if (~(tmp = *(p++)))
+                        goto found_middle_swap;
+                result += BITS_PER_LONG;
+                size -= BITS_PER_LONG;
         }
+        if (!size)
+                return result;
+        tmp = ext2_swabp(p);
+found_first:
+        tmp |= ~0UL << size;
+        if (tmp == ~0UL)        /* Are any bits zero? */
+                return result + size; /* Nope. Skip ffz */
+found_middle:
+        return result + ffz(tmp);
 
-        return offset;
+found_middle_swap:
+        return result + ffz(ext2_swab(tmp));
 }
 
-EXPORT_SYMBOL(find_next_bit);
+EXPORT_SYMBOL(generic_find_next_zero_le_bit);
+
+#endif /* __BIG_ENDIAN */