OpenCloudOS-Kernel/fs/ext2
David Howells f0d1b0b30d [PATCH] LOG2: Implement a general integer log2 facility in the kernel
This facility provides three entry points:

	ilog2()		Log base 2 of unsigned long
	ilog2_u32()	Log base 2 of u32
	ilog2_u64()	Log base 2 of u64

These facilities can either be used inside functions on dynamic data:

	int do_something(long q)
	{
		...;
		y = ilog2(x)
		...;
	}

Or can be used to statically initialise global variables with constant values:

	unsigned n = ilog2(27);

When performing static initialisation, the compiler will report "error:
initializer element is not constant" if asked to take a log of zero or of
something not reducible to a constant.  They treat negative numbers as
unsigned.

When not dealing with a constant, they fall back to using fls() which permits
them to use arch-specific log calculation instructions - such as BSR on
x86/x86_64 or SCAN on FRV - if available.

[akpm@osdl.org: MMC fix]
Signed-off-by: David Howells <dhowells@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: David Howells <dhowells@redhat.com>
Cc: Wojtek Kaniewski <wojtekka@toxygen.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-08 08:28:51 -08:00
..
Makefile [PATCH] Make EXT2_DEBUG work again 2006-06-25 10:01:12 -07:00
acl.c [PATCH] fs: Removing useless casts 2006-09-27 08:26:10 -07:00
acl.h [PATCH] remove <linux/xattr_acl.h> 2005-06-23 09:45:33 -07:00
balloc.c [PATCH] EXT2: Remove superblock lock contention in ext2_statfs 2006-09-19 07:59:59 -07:00
dir.c [PATCH] ext2: change uses of f_{dentry, vfsmnt} to use f_path 2006-12-08 08:28:41 -08:00
ext2.h [PATCH] BLOCK: Move the Ext2 device ioctl compat stuff to the Ext2 driver [try #6] 2006-09-30 20:52:29 +02:00
file.c [PATCH] Streamline generic_file_* interfaces and filemap cleanups 2006-10-01 00:39:28 -07:00
fsync.c [PATCH] ext2: cleanup: put_page and comment fix 2006-06-25 10:01:25 -07:00
ialloc.c [PATCH] inode-diet: Eliminate i_blksize from the inode structure 2006-09-27 08:26:18 -07:00
inode.c [PATCH] inode-diet: Eliminate i_blksize from the inode structure 2006-09-27 08:26:18 -07:00
ioctl.c [PATCH] ext2: change uses of f_{dentry, vfsmnt} to use f_path 2006-12-08 08:28:41 -08:00
namei.c [PATCH] r/o bind mounts: unlink: monitor i_nlink 2006-10-01 00:39:30 -07:00
super.c [PATCH] LOG2: Implement a general integer log2 facility in the kernel 2006-12-08 08:28:51 -08:00
symlink.c Fix nasty ncpfs symlink handling bug. 2005-08-19 18:02:56 -07:00
xattr.c [PATCH] Remove superfluous lock_super() in extN xattr code 2006-12-07 08:39:32 -08:00
xattr.h Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
xattr_security.c [PATCH] ext2: Enable atomic inode security labeling 2005-09-09 13:57:27 -07:00
xattr_trusted.c [PATCH] capable/capability.h (fs/) 2006-01-11 18:42:13 -08:00
xattr_user.c [PATCH] remove ext2 xattr permission checks 2006-01-10 08:01:30 -08:00
xip.c [PATCH] fix xip sparse file handling in ext2 2005-07-27 16:25:53 -07:00
xip.h [PATCH] xip: ext2: execute in place 2005-06-24 00:06:41 -07:00