Re: + proc-remove-useless-checks-in-proc_register.patch added to -mm tree

[Alexey Dobriyan <adobriyan@sw.ru>]

In fact, Andrew, please, drop this patch. Fixing yet another race in
proc would be done by suppying PDE's with valid ->proc_fops before
proc_register(), so this patch would be effectively reverted.

>      proc-remove-useless-checks-in-proc_register.patch

> Subject: proc: remove useless checks in proc_register()
> From: Alexey Dobriyan <adobriyan@sw.ru>
> 
> Before proc_register() all PDEs are created by proc_create() which doesn't set
> ->proc_iops and ->proc_fops -- they're NULL.  So those branches in
> proc_register() are always taken.
> 
> Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
> 
>  fs/proc/generic.c |   15 +++++----------
>  1 file changed, 5 insertions(+), 10 deletions(-)
> 
> diff -puN fs/proc/generic.c~proc-remove-useless-checks-in-proc_register fs/proc/generic.c
> --- a/fs/proc/generic.c~proc-remove-useless-checks-in-proc_register
> +++ a/fs/proc/generic.c
> @@ -526,19 +526,14 @@ static int proc_register(struct proc_dir
>  	dp->low_ino = i;
>  
>  	if (S_ISDIR(dp->mode)) {
> -		if (dp->proc_iops == NULL) {
> -			dp->proc_fops = &proc_dir_operations;
> -			dp->proc_iops = &proc_dir_inode_operations;
> -		}
> +		dp->proc_fops = &proc_dir_operations;
> +		dp->proc_iops = &proc_dir_inode_operations;
>  		dir->nlink++;
>  	} else if (S_ISLNK(dp->mode)) {
> -		if (dp->proc_iops == NULL)
> -			dp->proc_iops = &proc_link_inode_operations;
> +		dp->proc_iops = &proc_link_inode_operations;
>  	} else if (S_ISREG(dp->mode)) {
> -		if (dp->proc_fops == NULL)
> -			dp->proc_fops = &proc_file_operations;
> -		if (dp->proc_iops == NULL)
> -			dp->proc_iops = &proc_file_inode_operations;
> +		dp->proc_fops = &proc_file_operations;
> +		dp->proc_iops = &proc_file_inode_operations;
>  	}
>  
>  	spin_lock(&proc_subdir_lock);