[PATCH]is_power_of_2-ufs/super.c

[PATCH]is_power_of_2-ufs/super.c

[vignesh babu]

Replacing (n & (n-1)) in the context of power of 2 checks
with is_power_of_2

Signed-off-by: vignesh babu <vignesh.babu@wipro.com>
--- 
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?"

[KJ] [PATCH]is_power_of_2-ufs/super.c

[vignesh babu]

Replacing (n & (n-1)) in the context of power of 2 checks
with is_power_of_2

Signed-off-by: vignesh babu <vignesh.babu@wipro.com>
--- 
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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Kernel-janitors mailing list
Kernel-janitors@lists.linux-foundation.org
https://lists.linux-foundation.org/mailman/listinfo/kernel-janitors

[KJ] Re: [PATCH]is_power_of_2-ufs/super.c

[Evgeniy Dushistov]

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 <vignesh.babu@wipro.com>

Acked-by: Evgeniy Dushistov <dushistov@mail.ru>

> --- 
> 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?"
> 
> 
> 
> The information contained in this electronic message and any attachments to this message are intended for the exclusive use of the addressee(s) and may contain proprietary, confidential or privileged information. If you are not the intended recipient, you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately and destroy all copies of this message and any attachments. 
> 
> WARNING: Computer viruses can be transmitted via email. The recipient should check this email and any attachments for the presence of viruses. The company accepts no liability for any damage caused by any virus transmitted by this email.
>  
> www.wipro.com

-- 
/Evgeniy

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Re: [PATCH]is_power_of_2-ufs/super.c

[Evgeniy Dushistov]

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 <vignesh.babu@wipro.com>

Acked-by: Evgeniy Dushistov <dushistov@mail.ru>

> --- 
> 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?"
> 
> 
> 
> The information contained in this electronic message and any attachments to this message are intended for the exclusive use of the addressee(s) and may contain proprietary, confidential or privileged information. If you are not the intended recipient, you should not disseminate, distribute or copy this e-mail. Please notify the sender immediately and destroy all copies of this message and any attachments. 
> 
> WARNING: Computer viruses can be transmitted via email. The recipient should check this email and any attachments for the presence of viruses. The company accepts no liability for any damage caused by any virus transmitted by this email.
>  
> www.wipro.com

-- 
/Evgeniy

[KJ] Re: [PATCH]is_power_of_2-ufs/super.c

[Johannes Weiner]

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
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Re: [PATCH]is_power_of_2-ufs/super.c

[Johannes Weiner]

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

Re: [PATCH]is_power_of_2-ufs/super.c

[vignesh babu]

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?"

[KJ] Re: [PATCH]is_power_of_2-ufs/super.c

[vignesh babu]

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?"

_______________________________________________
Kernel-janitors mailing list
Kernel-janitors@lists.linux-foundation.org
https://lists.linux-foundation.org/mailman/listinfo/kernel-janitors

[KJ] Re: [PATCH]is_power_of_2-ufs/super.c

[Robert P. J. Day]

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
====================================
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Re: [PATCH]is_power_of_2-ufs/super.c

[Robert P. J. Day]

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
========================================================================