linux-kernel - Re: [PATCH v2] scsi: sli4: Remove the buggy code

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20230817105252.GA14370@yadro.com>
Date:   Thu, 17 Aug 2023 13:52:52 +0300
From:   Dmitry Bogdanov <d.bogdanov@...ro.com>
To:     <coolrrsh@...il.com>
CC:     <james.smart@...adcom.com>, <ram.vegesna@...adcom.com>,
        <jejb@...ux.ibm.com>, <martin.petersen@...cle.com>,
        <rdunlap@...radead.org>, <linux-scsi@...r.kernel.org>,
        <target-devel@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-kernel-mentees@...ts.linuxfoundation.org>
Subject: Re: [PATCH v2] scsi: sli4: Remove the buggy code

On Thu, Aug 17, 2023 at 04:07:51PM +0530, coolrrsh@...il.com wrote:
> 
> From: Rajeshwar R Shinde <coolrrsh@...il.com>
> 
> In the function sli_xmit_bls_rsp64_wqe, the 'if' and 'else' conditions
> evaluates the same expression and gives same output. Also the variable
> bls->local_n_port_id_dword is not used anywhere. Therefore removing the
> redundant code.
> 
> This fixes coccinelle warning such as:
> drivers/scsi/elx/libefc_sli/sli4.c:2320:2-4: WARNING: possible
> condition with no effect (if == else)
> 
> Signed-off-by: Rajeshwar R Shinde <coolrrsh@...il.com>
> ---
> v1->v2
> Modified patch and verified with checkpatch.pl.
> 
> ---
>  drivers/scsi/elx/libefc_sli/sli4.c | 7 -------
>  1 file changed, 7 deletions(-)
> 
> diff --git a/drivers/scsi/elx/libefc_sli/sli4.c b/drivers/scsi/elx/libefc_sli/sli4.c
> index 8f96049f62dd..af661b769464 100644
> --- a/drivers/scsi/elx/libefc_sli/sli4.c
> +++ b/drivers/scsi/elx/libefc_sli/sli4.c
> @@ -2317,13 +2317,6 @@ sli_xmit_bls_rsp64_wqe(struct sli4 *sli, void *buf,
>                 SLI4_GENERIC_CONTEXT_VPI << SLI4_BLS_RSP_WQE_CT_SHFT;
>                 bls->context_tag = cpu_to_le16(params->vpi);
> 
> -               if (params->s_id != U32_MAX)
> -                       bls->local_n_port_id_dword |=
> -                               cpu_to_le32(params->s_id & 0x00ffffff);
> -               else
> -                       bls->local_n_port_id_dword |=
> -                               cpu_to_le32(params->s_id & 0x00ffffff);
> -

omg, it is not an unused variable. Whole bls is a HW descriptor, all of
its variables are used by HW. You should keep v1 version of the patch.
According to the comment at the beginning of the funciton s_id here shall
be != U32_MAX. That is an explanation for your v1 patch.

>                 dw_ridflags = (dw_ridflags & ~SLI4_BLS_RSP_RID) |
>                                (params->d_id & SLI4_BLS_RSP_RID);
> 
> --
> 2.25.1
>