[patch] proc: copy_to_user() returns unsigned

[patch] proc: copy_to_user() returns unsigned

[Dan Carpenter]

copy_to_user() returns the number of bytes left to be copied.

This was a typo from: d82ef020cf31504c816803b1def94eb5ff173363
"proc: pagemap: Hold mmap_sem during page walk".

Signed-off-by: Dan Carpenter <error27@gmail.com>

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 0962739..bfb2773 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -799,7 +799,7 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
 		start_vaddr = end;
 
 		len = min(count, PM_ENTRY_BYTES * pm.pos);
-		if (copy_to_user(buf, pm.buffer, len) < 0) {
+		if (copy_to_user(buf, pm.buffer, len)) {
 			ret = -EFAULT;
 			goto out_free;
 		}

Re: [patch] proc: copy_to_user() returns unsigned

[Minchan Kim]

I got confused when I see the title of patch.
That's because I understood copy_to_user returns unsigned.
Please, change title to describe your patch.

[PATCH] proc : fix wrong usage of copy_to_user's return value.

Maybe you could name it well than me who is a not native English.

On Tue, Apr 6, 2010 at 7:45 PM, Dan Carpenter <error27@gmail.com> wrote:
> copy_to_user() returns the number of bytes left to be copied.
>
> This was a typo from: d82ef020cf31504c816803b1def94eb5ff173363
> "proc: pagemap: Hold mmap_sem during page walk".
>
> Signed-off-by: Dan Carpenter <error27@gmail.com>
Reviewed-by: Minchan Kim <minchan.kim@gmail.com>



-- 
Kind regards,
Minchan Kim

Re: [patch] proc: copy_to_user() returns unsigned

[KOSAKI Motohiro]

> copy_to_user() returns the number of bytes left to be copied.
> 
> This was a typo from: d82ef020cf31504c816803b1def94eb5ff173363
> "proc: pagemap: Hold mmap_sem during page walk".
> 
> Signed-off-by: Dan Carpenter <error27@gmail.com>
> 
> diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
> index 0962739..bfb2773 100644
> --- a/fs/proc/task_mmu.c
> +++ b/fs/proc/task_mmu.c
> @@ -799,7 +799,7 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
>  		start_vaddr = end;
>  
>  		len = min(count, PM_ENTRY_BYTES * pm.pos);
> -		if (copy_to_user(buf, pm.buffer, len) < 0) {
> +		if (copy_to_user(buf, pm.buffer, len)) {
>  			ret = -EFAULT;
>  			goto out_free;
>  		}

  Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>


However I don't think this patch is kernel-janitors material. it should
be just merged mainline soon.

Re: [patch] proc: copy_to_user() returns unsigned

[Matt Mackall]

On Tue, 2010-04-06 at 13:45 +0300, Dan Carpenter wrote:
> copy_to_user() returns the number of bytes left to be copied.
> 
> This was a typo from: d82ef020cf31504c816803b1def94eb5ff173363
> "proc: pagemap: Hold mmap_sem during page walk".
> 
> Signed-off-by: Dan Carpenter <error27@gmail.com>
> 
> diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
> index 0962739..bfb2773 100644
> --- a/fs/proc/task_mmu.c
> +++ b/fs/proc/task_mmu.c
> @@ -799,7 +799,7 @@ static ssize_t pagemap_read(struct file *file, char __user *buf,
>  		start_vaddr = end;
>  
>  		len = min(count, PM_ENTRY_BYTES * pm.pos);
> -		if (copy_to_user(buf, pm.buffer, len) < 0) {
> +		if (copy_to_user(buf, pm.buffer, len)) {
>  			ret = -EFAULT;
>  			goto out_free;
>  		}

Acked-by: Matt Mackall <mpm@selenic.com>

Linus, please take this one too.

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