Re: [PATCH] ipmi: ssif_bmc: Move smbus_cmd assignment after cleanup

[Corey Minyard <corey@minyard.net>]

On Fri, Jan 03, 2025 at 10:44:46AM +0700, Quan Nguyen wrote:
> 
> 
> On 01/01/2025 23:54, Cosmo Chou wrote:
> > Move smbus_cmd assignment to the end of process_smbus_cmd() to ensure
> > the new command is not lost when complete_response() is triggered.
> > 
> 
> Thanks Cosmo for the catch.
> 
> And, IMHO, the root cause is the memset() on part buffer called in
> complete_response() is not quite correct. In the current implementation, the
> complete_response() should only be called when the READ is completed, ie:
> only on I2C_SLAVE_STOP of READ transaction, otherwise all the info of
> current on-going request will be mistakenly cleared as in this case.
> 
> This patch is good and I wonder if we can make this a bit further as below?

Yes, this is probably more future proof.

Can you send me a formal patch, with a "Found-by:" for Cosmo?  I'll
replace Cosmo's patch.

Thanks,

-corey

> 
> diff --git a/drivers/char/ipmi/ssif_bmc.c b/drivers/char/ipmi/ssif_bmc.c
> index a14fafc583d4..310f17dd9511 100644
> --- a/drivers/char/ipmi/ssif_bmc.c
> +++ b/drivers/char/ipmi/ssif_bmc.c
> @@ -292,7 +292,6 @@ static void complete_response(struct ssif_bmc_ctx
> *ssif_bmc)
>         ssif_bmc->nbytes_processed = 0;
>         ssif_bmc->remain_len = 0;
>         ssif_bmc->busy = false;
> -       memset(&ssif_bmc->part_buf, 0, sizeof(struct ssif_part_buffer));
>         wake_up_all(&ssif_bmc->wait_queue);
>  }
> 
> @@ -744,9 +743,11 @@ static void on_stop_event(struct ssif_bmc_ctx
> *ssif_bmc, u8 *val)
>                         ssif_bmc->aborting = true;
>                 }
>         } else if (ssif_bmc->state == SSIF_RES_SENDING) {
> -               if (ssif_bmc->is_singlepart_read || ssif_bmc->block_num ==
> 0xFF)
> +               if (ssif_bmc->is_singlepart_read || ssif_bmc->block_num ==
> 0xFF) {
> +                       memset(&ssif_bmc->part_buf, 0, sizeof(struct
> ssif_part_buffer));
>                         /* Invalidate response buffer to denote it is sent
> */
>                         complete_response(ssif_bmc);
> +               }
>                 ssif_bmc->state = SSIF_READY;
>         }
> 
> Thanks and Happy New Year.
> - Quan