linux-kernel - Re: [PATCH] ipmi:ssif: compare block number correctly for multi-part return messages

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Message-ID: <20190424135340.GD6623@minyard.net>
Date:   Wed, 24 Apr 2019 08:53:40 -0500
From:   Corey Minyard <minyard@....org>
To:     Kamlakant Patel <kamlakantp@...vell.com>
Cc:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Jayachandran Chandrasekharan Nair <jnair@...vell.com>,
        "openipmi-developer@...ts.sourceforge.net" 
        <openipmi-developer@...ts.sourceforge.net>
Subject: Re: [PATCH] ipmi:ssif: compare block number correctly for multi-part
 return messages

On Wed, Apr 24, 2019 at 11:50:43AM +0000, Kamlakant Patel wrote:
> According to ipmi spec, block number is a number that is incremented,
> starting with 0, for each new block of message data returned using the
> Middle transaction.
> 
> Here, the 'blocknum' is data[0] which always starts from zero(0) and
> 'ssif_info->multi_pos' starts from 1.
> So, we need to add +1 to blocknum while comparing with multi_pos.

Indeed, I think you are right.  I hope there's no other hardware that
mis-interprets this like I did.  I'll need to fix my qemu simulation,
too.  The funny thing is, the comment is correct. Hmm.

I'll hand-apply this, as it has DOS newlines, too.

-corey

> 
> This change fixes ("ipmi:ssif: Fix handling of multi-part return
> messages").
> 
> Reported-by: Kiran Kolukuluru <kirank@....com>
> Signed-off-by: Kamlakant Patel <kamlakantp@...vell.com>
> ---
>  drivers/char/ipmi/ipmi_ssif.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/char/ipmi/ipmi_ssif.c b/drivers/char/ipmi/ipmi_ssif.c
> index 8b5aec5..2b03845 100644
> --- a/drivers/char/ipmi/ipmi_ssif.c
> +++ b/drivers/char/ipmi/ipmi_ssif.c
> @@ -727,7 +727,7 @@ static void msg_done_handler(struct ssif_info *ssif_info, int result,
>  			/* End of read */
>  			len = ssif_info->multi_len;
>  			data = ssif_info->data;
> -		} else if (blocknum != ssif_info->multi_pos) {
> +		} else if (blocknum + 1 != ssif_info->multi_pos) {
>  			/*
>  			 * Out of sequence block, just abort.  Block
>  			 * numbers start at zero for the second block,
> -- 
> 1.8.3.1
>