[RFC][PATCH 2.4 1/4] inotify 0.22 2.4.x backport - find_next_bit

[Mihai Rusu <dizzy@schlund.ro>]

Hi

This is the find_next_bit implementation from 2.6.11 vanilla. Needed by
"idr.c".

-- 
Mihai Rusu
Linux System Development

Schlund + Partner AG   Tel         : +40-21-231-2544
Str Mircea Eliade 18   EMail       : dizzy@schlund.ro
Sect 1, Bucuresti
71295, Romania




 include/linux/bitops.h |    2 +
 lib/Makefile           |    2 -
 lib/find_next_bit.c    |   55 +++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 58 insertions(+), 1 deletion(-)

diff -uNr linux-2.4.30.orig/include/linux/bitops.h linux-2.4.30/include/linux/bitops.h
--- linux-2.4.30.orig/include/linux/bitops.h	2001-11-22 21:46:18.000000000 +0200
+++ linux-2.4.30/include/linux/bitops.h	2005-05-09 13:13:18.000000000 +0300
@@ -66,6 +66,8 @@
         return (res & 0x0F) + ((res >> 4) & 0x0F);
 }
 
+int find_next_bit(const unsigned long *addr, int size, int offset);
+
 #include <asm/bitops.h>
 
 
diff -uNr linux-2.4.30.orig/lib/Makefile linux-2.4.30/lib/Makefile
--- linux-2.4.30.orig/lib/Makefile	2004-04-14 16:05:40.000000000 +0300
+++ linux-2.4.30/lib/Makefile	2005-05-09 13:16:49.000000000 +0300
@@ -12,7 +12,7 @@
 	       rbtree.o crc32.o firmware_class.o
 
 obj-y := errno.o ctype.o string.o vsprintf.o brlock.o cmdline.o \
-	 bust_spinlocks.o rbtree.o dump_stack.o
+	 bust_spinlocks.o rbtree.o dump_stack.o find_next_bit.o
 
 obj-$(CONFIG_FW_LOADER) += firmware_class.o
 obj-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
diff -uNr linux-2.4.30.orig/lib/find_next_bit.c linux-2.4.30/lib/find_next_bit.c
--- linux-2.4.30.orig/lib/find_next_bit.c	1970-01-01 02:00:00.000000000 +0200
+++ linux-2.4.30/lib/find_next_bit.c	2005-05-09 13:13:18.000000000 +0300
@@ -0,0 +1,55 @@
+/* find_next_bit.c: fallback find next bit implementation
+ *
+ * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/bitops.h>
+
+int find_next_bit(const unsigned long *addr, int size, int offset)
+{
+	const unsigned long *base;
+	const int NBITS = sizeof(*addr) * 8;
+	unsigned long tmp;
+
+	base = addr;
+	if (offset) {
+		int suboffset;
+
+		addr += offset / NBITS;
+
+		suboffset = offset % NBITS;
+		if (suboffset) {
+			tmp = *addr;
+			tmp >>= suboffset;
+			if (tmp)
+				goto finish;
+		}
+
+		addr++;
+	}
+
+	while ((tmp = *addr) == 0)
+		addr++;
+
+	offset = (addr - base) * NBITS;
+
+ finish:
+	/* count the remaining bits without using __ffs() since that takes a 32-bit arg */
+	while (!(tmp & 0xff)) {
+		offset += 8;
+		tmp >>= 8;
+	}
+
+	while (!(tmp & 1)) {
+		offset++;
+		tmp >>= 1;
+	}
+
+	return offset;
+}