linux/fs/ext3
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
..
acl.c [PATCH] fs: Removing useless casts 2006-09-27 08:26:10 -07:00
acl.h
balloc.c [PATCH] ext3 balloc: fix _with_rsv freeze 2006-12-07 08:39:48 -08:00
bitmap.c [PATCH] ext3 and jbd cleanup: remove whitespace 2006-09-27 08:26:09 -07:00
dir.c [PATCH] ext3: change uses of f_{dentry, vfsmnt} to use f_path 2006-12-08 08:28:41 -08:00
ext3_jbd.c [PATCH] ext3: uninline large functions 2006-12-07 08:39:35 -08:00
file.c [PATCH] ext3: change uses of f_{dentry, vfsmnt} to use f_path 2006-12-08 08:28:41 -08:00
fsync.c [PATCH] ext3 and jbd cleanup: remove whitespace 2006-09-27 08:26:09 -07:00
hash.c [PATCH] ext3: More whitespace cleanups 2006-09-27 08:26:10 -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] retries in ext3_prepare_write() violate ordering requirements 2006-12-07 08:39:37 -08:00
ioctl.c [PATCH] ext3: change uses of f_{dentry, vfsmnt} to use f_path 2006-12-08 08:28:41 -08:00
Makefile [PATCH] ext3: uninline large functions 2006-12-07 08:39:35 -08:00
namei.c [PATCH] ext3: change uses of f_{dentry, vfsmnt} to use f_path 2006-12-08 08:28:41 -08:00
namei.h
resize.c [PATCH] fs: Removing useless casts 2006-09-27 08:26:10 -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
xattr.c [PATCH] Remove superfluous lock_super() in extN xattr code 2006-12-07 08:39:32 -08:00
xattr.h
xattr_security.c
xattr_trusted.c
xattr_user.c