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SubjectRe: [PATCH] proc/base: Skip assignment to len when there is no error on d_path in do_proc_readlink.
Kaitao Cheng <pilgrimtao@gmail.com> writes:

> we don't need {len = PTR_ERR(pathname)} when IS_ERR(pathname) is false,
> it's better to move it into if(IS_ERR(pathname)){}.

Please look at the generated code.

I believe you will find that your change will generate worse assembly.

Eric


> Signed-off-by: Kaitao Cheng <pilgrimtao@gmail.com>
> ---
> fs/proc/base.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/fs/proc/base.c b/fs/proc/base.c
> index d86c0afc8a85..9509e0d42610 100644
> --- a/fs/proc/base.c
> +++ b/fs/proc/base.c
> @@ -1753,9 +1753,10 @@ static int do_proc_readlink(struct path *path, char __user *buffer, int buflen)
> return -ENOMEM;
>
> pathname = d_path(path, tmp, PAGE_SIZE);
> - len = PTR_ERR(pathname);
> - if (IS_ERR(pathname))
> + if (IS_ERR(pathname)) {
> + len = PTR_ERR(pathname);
> goto out;
> + }
> len = tmp + PAGE_SIZE - 1 - pathname;
>
> if (len > buflen)

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