[PATCH] proc: fix kflags to uflags copying in /proc/kpageflags

[PATCH] proc: fix kflags to uflags copying in /proc/kpageflags

[Wu Fengguang]

Fix kpf_copy_bit(src,dst) to be kpf_copy_bit(dst,src) to match the
actual call patterns, e.g. kpf_copy_bit(kflags, KPF_LOCKED, PG_locked).

This misplacement of src/dst only affected reporting of PG_writeback,
PG_reclaim and PG_buddy. For others kflags==uflags so not affected.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---

This is a tested and trivial no-side-effect fix.
I'd suggest it for 2.6.29-rc7 and 2.6.28.X kernels.

diff --git a/fs/proc/page.c b/fs/proc/page.c
index 2d13451..e998383 100644
--- a/fs/proc/page.c
+++ b/fs/proc/page.c
@@ -80,7 +80,7 @@ static const struct file_operations proc_kpagecount_operations = {
 #define KPF_RECLAIM    9
 #define KPF_BUDDY     10
 
-#define kpf_copy_bit(flags, srcpos, dstpos) (((flags >> srcpos) & 1) << dstpos)
+#define kpf_copy_bit(flags, dstpos, srcpos) (((flags >> srcpos) & 1) << dstpos)
 
 static ssize_t kpageflags_read(struct file *file, char __user *buf,
 			     size_t count, loff_t *ppos)

Re: [PATCH] proc: fix kflags to uflags copying in /proc/kpageflags

[KOSAKI Motohiro]

> Fix kpf_copy_bit(src,dst) to be kpf_copy_bit(dst,src) to match the
> actual call patterns, e.g. kpf_copy_bit(kflags, KPF_LOCKED, PG_locked).
> 
> This misplacement of src/dst only affected reporting of PG_writeback,
> PG_reclaim and PG_buddy. For others kflags==uflags so not affected.
> 
> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
> ---
> 
> This is a tested and trivial no-side-effect fix.
> I'd suggest it for 2.6.29-rc7 and 2.6.28.X kernels.
> 
> diff --git a/fs/proc/page.c b/fs/proc/page.c
> index 2d13451..e998383 100644
> --- a/fs/proc/page.c
> +++ b/fs/proc/page.c
> @@ -80,7 +80,7 @@ static const struct file_operations proc_kpagecount_operations = {
>  #define KPF_RECLAIM    9
>  #define KPF_BUDDY     10
>  
> -#define kpf_copy_bit(flags, srcpos, dstpos) (((flags >> srcpos) & 1) << dstpos)
> +#define kpf_copy_bit(flags, dstpos, srcpos) (((flags >> srcpos) & 1) << dstpos)

Good catch! :)
	Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>


but don't worry. the number of this interface user is very few.

Re: [PATCH] proc: fix kflags to uflags copying in /proc/kpageflags

[Wu Fengguang]

On Wed, Mar 11, 2009 at 03:17:58AM +0200, KOSAKI Motohiro wrote:
> > Fix kpf_copy_bit(src,dst) to be kpf_copy_bit(dst,src) to match the
> > actual call patterns, e.g. kpf_copy_bit(kflags, KPF_LOCKED, PG_locked).
> > 
> > This misplacement of src/dst only affected reporting of PG_writeback,
> > PG_reclaim and PG_buddy. For others kflags==uflags so not affected.
> > 
> > Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
> > ---
> > 
> > This is a tested and trivial no-side-effect fix.
> > I'd suggest it for 2.6.29-rc7 and 2.6.28.X kernels.
> > 
> > diff --git a/fs/proc/page.c b/fs/proc/page.c
> > index 2d13451..e998383 100644
> > --- a/fs/proc/page.c
> > +++ b/fs/proc/page.c
> > @@ -80,7 +80,7 @@ static const struct file_operations proc_kpagecount_operations = {
> >  #define KPF_RECLAIM    9
> >  #define KPF_BUDDY     10
> >  
> > -#define kpf_copy_bit(flags, srcpos, dstpos) (((flags >> srcpos) & 1) << dstpos)
> > +#define kpf_copy_bit(flags, dstpos, srcpos) (((flags >> srcpos) & 1) << dstpos)
> 
> Good catch! :)
> 	Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>

Thank you :)

> 
> but don't worry. the number of this interface user is very few.

Yeah, so few users that I have to write the tools by myself ;-)

Thanks,
Fengguang