Replacing (n & (n-1)) in the context of power of 2 checks
with is_power_of_2
Signed-off-by: vignesh babu <[email protected]>
---
diff --git a/fs/ufs/super.c b/fs/ufs/super.c
index 22ff6ed..2b30116 100644
--- a/fs/ufs/super.c
+++ b/fs/ufs/super.c
@@ -87,6 +87,7 @@
#include <linux/smp_lock.h>
#include <linux/buffer_head.h>
#include <linux/vfs.h>
+#include <linux/log2.h>
#include "swab.h"
#include "util.h"
@@ -854,7 +855,7 @@ magic_found:
uspi->s_fmask = fs32_to_cpu(sb, usb1->fs_fmask);
uspi->s_fshift = fs32_to_cpu(sb, usb1->fs_fshift);
- if (uspi->s_fsize & (uspi->s_fsize - 1)) {
+ if (!is_power_of_2(uspi->s_fsize)) {
printk(KERN_ERR "ufs_read_super: fragment size %u is not a power of 2\n",
uspi->s_fsize);
goto failed;
@@ -869,7 +870,7 @@ magic_found:
uspi->s_fsize);
goto failed;
}
- if (uspi->s_bsize & (uspi->s_bsize - 1)) {
+ if (!is_power_of_2(uspi->s_bsize)) {
printk(KERN_ERR "ufs_read_super: block size %u is not a power of 2\n",
uspi->s_bsize);
goto failed;
--
Vignesh Babu BM
_____________________________________________________________
"Why is it that every time I'm with you, makes me believe in magic?"
On Thu, Jun 14, 2007 at 01:39:18PM +0530, vignesh babu wrote:
>
>
> Replacing (n & (n-1)) in the context of power of 2 checks
> with is_power_of_2
>
> Signed-off-by: vignesh babu <[email protected]>
Acked-by: Evgeniy Dushistov <[email protected]>
> ---
> diff --git a/fs/ufs/super.c b/fs/ufs/super.c
> index 22ff6ed..2b30116 100644
> --- a/fs/ufs/super.c
> +++ b/fs/ufs/super.c
> @@ -87,6 +87,7 @@
> #include <linux/smp_lock.h>
> #include <linux/buffer_head.h>
> #include <linux/vfs.h>
> +#include <linux/log2.h>
>
> #include "swab.h"
> #include "util.h"
> @@ -854,7 +855,7 @@ magic_found:
> uspi->s_fmask = fs32_to_cpu(sb, usb1->fs_fmask);
> uspi->s_fshift = fs32_to_cpu(sb, usb1->fs_fshift);
>
> - if (uspi->s_fsize & (uspi->s_fsize - 1)) {
> + if (!is_power_of_2(uspi->s_fsize)) {
> printk(KERN_ERR "ufs_read_super: fragment size %u is not a power of 2\n",
> uspi->s_fsize);
> goto failed;
> @@ -869,7 +870,7 @@ magic_found:
> uspi->s_fsize);
> goto failed;
> }
> - if (uspi->s_bsize & (uspi->s_bsize - 1)) {
> + if (!is_power_of_2(uspi->s_bsize)) {
> printk(KERN_ERR "ufs_read_super: block size %u is not a power of 2\n",
> uspi->s_bsize);
> goto failed;
>
> --
> Vignesh Babu BM
> _____________________________________________________________
> "Why is it that every time I'm with you, makes me believe in magic?"
>
>
>
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--
/Evgeniy
Hi,
On Thu, Jun 14, 2007 at 01:39:18PM +0530, vignesh babu wrote:
> Replacing (n & (n-1)) in the context of power of 2 checks
> with is_power_of_2
You might want to run
egrep -R '([a-zA-Z0-9_.>]+) *& *\(\1 *- *1\)' /usr/src/linux
This does not match if the check is broken into multiple lines, though.
Still, 66 matches so far. Perhaps a big patch that removes most of these
occurrences would be more appropriate.
Hannes
Thanks Hannes, Im on it...
On Mon, 2007-06-25 at 14:13 +0200, Johannes Weiner wrote:
> egrep -R '([a-zA-Z0-9_.>]+) *& *\(\1 *- *1\)' /usr/src/linux
--
Vignesh Babu BM
_____________________________________________________________
"Why is it that every time I'm with you, makes me believe in magic?"
On Mon, 25 Jun 2007, Johannes Weiner wrote:
> Hi,
>
> On Thu, Jun 14, 2007 at 01:39:18PM +0530, vignesh babu wrote:
> > Replacing (n & (n-1)) in the context of power of 2 checks
> > with is_power_of_2
>
> You might want to run
>
> egrep -R '([a-zA-Z0-9_.>]+) *& *\(\1 *- *1\)' /usr/src/linux
>
> This does not match if the check is broken into multiple lines,
> though. Still, 66 matches so far. Perhaps a big patch that removes
> most of these occurrences would be more appropriate.
this cleanup project is already well documented here:
http://fsdev.net/wiki/index.php?title=Power_of_2_stuff
and it's unlikely that you'd get a big patch in that tries to do all
of that at once. it's much easier to do it a subsystem at a time.
rday
p.s. that wiki page could probably use some updating.
--
========================================================================
Robert P. J. Day
Linux Consulting, Training and Annoying Kernel Pedantry
Waterloo, Ontario, CANADA
http://fsdev.net/wiki/index.php?title=Main_Page
========================================================================