linux-kernel - Re: [PATCH 01/10] smb/client: reduce loop count in map_smb2_to_linux

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Message-ID: <CAH2r5mu25T8sBO4P25St_H0F0KMenn+5QGWx1Tfa+=6AsF6aNw@mail.gmail.com>
Date: Wed, 3 Dec 2025 23:49:29 -0600
From: Steve French <smfrench@...il.com>
To: chenxiaosong.chenxiaosong@...ux.dev
Cc: linkinjeon@...nel.org, linkinjeon@...ba.org, linux-cifs@...r.kernel.org, 
	linux-kernel@...r.kernel.org, chenxiaosong@...nxiaosong.com, 
	ChenXiaoSong <chenxiaosong@...inos.cn>, samba-technical <samba-technical@...ts.samba.org>
Subject: Re: [PATCH 01/10] smb/client: reduce loop count in
 map_smb2_to_linux_error() by half

Have merged the first three patches (see below) in this series into
cifs-2.6.git for-next pending additional review and testing.   The
other seven may also be ok - but want to look more carefully at them,
more review appreciated

ba521f56912f (HEAD -> for-next, origin/for-next) smb: add two elements
to smb2_error_map_table array
905d8999d67d smb/client: remove unused elements from smb2_error_map_table array
26866d690bd1 smb/client: reduce loop count in map_smb2_to_linux_error() by half

On Wed, Dec 3, 2025 at 10:59 PM <chenxiaosong.chenxiaosong@...ux.dev> wrote:
>
> From: ChenXiaoSong <chenxiaosong@...inos.cn>
>
> The smb2_error_map_table array currently has 1740 elements. When searching
> for the last element and calling smb2_print_status(), 3480 comparisons
> are needed.
>
> The loop in smb2_print_status() is unnecessary, smb2_print_status() can be
> removed, and only iterate over the array once, printing the message when
> the target status code is found.
>
> Signed-off-by: ChenXiaoSong <chenxiaosong@...inos.cn>
> ---
>  fs/smb/client/smb2maperror.c | 30 ++++++------------------------
>  1 file changed, 6 insertions(+), 24 deletions(-)
>
> diff --git a/fs/smb/client/smb2maperror.c b/fs/smb/client/smb2maperror.c
> index 12c2b868789f..d1df6e518d21 100644
> --- a/fs/smb/client/smb2maperror.c
> +++ b/fs/smb/client/smb2maperror.c
> @@ -2418,24 +2418,6 @@ static const struct status_to_posix_error smb2_error_map_table[] = {
>         {0, 0, NULL}
>  };
>
> -/*****************************************************************************
> - Print an error message from the status code
> - *****************************************************************************/
> -static void
> -smb2_print_status(__le32 status)
> -{
> -       int idx = 0;
> -
> -       while (smb2_error_map_table[idx].status_string != NULL) {
> -               if ((smb2_error_map_table[idx].smb2_status) == status) {
> -                       pr_notice("Status code returned 0x%08x %s\n", status,
> -                                 smb2_error_map_table[idx].status_string);
> -               }
> -               idx++;
> -       }
> -       return;
> -}
> -
>  int
>  map_smb2_to_linux_error(char *buf, bool log_err)
>  {
> @@ -2452,16 +2434,16 @@ map_smb2_to_linux_error(char *buf, bool log_err)
>                 return 0;
>         }
>
> -       /* mask facility */
> -       if (log_err && (smb2err != STATUS_MORE_PROCESSING_REQUIRED) &&
> -           (smb2err != STATUS_END_OF_FILE))
> -               smb2_print_status(smb2err);
> -       else if (cifsFYI & CIFS_RC)
> -               smb2_print_status(smb2err);
> +       log_err = (log_err && (smb2err != STATUS_MORE_PROCESSING_REQUIRED) &&
> +                  (smb2err != STATUS_END_OF_FILE)) ||
> +                 (cifsFYI & CIFS_RC);
>
>         for (i = 0; i < sizeof(smb2_error_map_table) /
>                         sizeof(struct status_to_posix_error); i++) {
>                 if (smb2_error_map_table[i].smb2_status == smb2err) {
> +                       if (log_err)
> +                               pr_notice("Status code returned 0x%08x %s\n", smb2err,
> +                                         smb2_error_map_table[i].status_string);
>                         rc = smb2_error_map_table[i].posix_error;
>                         break;
>                 }
> --
> 2.43.0
>


-- 
Thanks,

Steve