Re: [PATCH] vfs: does call expand_files when needed

["Américo Wang" <xiyou.wangcong@gmail.com>]

On Wed, Nov 18, 2009 at 1:54 PM, Liu Aleaxander <aleaxander@gmail.com> wrote:
> From: Liu Aleaxander <Aleaxander@gmail.com>
> Date: Wed, 18 Nov 2009 10:59:09 +0800
> Subject: [PATCH] vfs: does call expand_files when needed
>
> I don't think we should call expand_files every time we open a
> file for a new unused fd, so does the expand when necessary.
>
> Signed-off-by: Liu Aleaxander <Aleaxander@gmail.com>
> ---
>  fs/file.c |   27 ++++++++++++++-------------
>  1 files changed, 14 insertions(+), 13 deletions(-)
>
> diff --git a/fs/file.c b/fs/file.c
> index 87e1290..3f3d0fc 100644
> --- a/fs/file.c
> +++ b/fs/file.c
> @@ -452,22 +452,22 @@ repeat:
>        if (fd < files->next_fd)
>                fd = files->next_fd;
>
> -       if (fd < fdt->max_fds)
> +       if (likely(fd < fdt->max_fds)) {
>                fd = find_next_zero_bit(fdt->open_fds->fds_bits,
>                                           fdt->max_fds, fd);
> -
> -       error = expand_files(files, fd);
> -       if (error < 0)
> -               goto out;
> -
> -       /*
> -        * If we needed to expand the fs array we
> -        * might have blocked - try again.
> -        */
> -       if (error)
> -               goto repeat;
> -
> +       } else {
> +               error = expand_files(files, fd);


In expand_files(), it has the check for
' < fdt->max_fds', so this change is not necessary.


> +               if (error < 0)
> +                       goto out;
> +
> +               /*
> +                * If we needed to expand the fs array we
> +                * might have blocked - try again.
> +                */
> +               if (error)
> +                       goto repeat;
> +       }
> +
>        if (start <= files->next_fd)
>                files->next_fd = fd + 1;
>
> --
> 1.6.2.5
>
> --
> regards
> Liu Aleaxander
> --
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