Re: [PATCH] scsi: ibmvscsi: Don't use rc uninitialized in ibmvscsi_do_work

From: Nathan Chancellor
Date: Sun Jun 02 2019 - 23:27:37 EST


Hi Michael,

On Sun, Jun 02, 2019 at 08:15:38PM +1000, Michael Ellerman wrote:
> Hi Nathan,
>
> It's always preferable IMHO to keep any initialisation as localised as
> possible, so that the compiler can continue to warn about uninitialised
> usages elsewhere. In this case that would mean doing the rc = 0 in the
> switch, something like:

I am certainly okay with implementing this in a v2. I mulled over which
would be preferred, I suppose I guessed wrong :) Thank you for the
review and input.

>
> diff --git a/drivers/scsi/ibmvscsi/ibmvscsi.c b/drivers/scsi/ibmvscsi/ibmvscsi.c
> index 727c31dc11a0..7ee5755cf636 100644
> --- a/drivers/scsi/ibmvscsi/ibmvscsi.c
> +++ b/drivers/scsi/ibmvscsi/ibmvscsi.c
> @@ -2123,9 +2123,6 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
>
> spin_lock_irqsave(hostdata->host->host_lock, flags);
> switch (hostdata->action) {
> - case IBMVSCSI_HOST_ACTION_NONE:
> - case IBMVSCSI_HOST_ACTION_UNBLOCK:
> - break;
> case IBMVSCSI_HOST_ACTION_RESET:
> spin_unlock_irqrestore(hostdata->host->host_lock, flags);
> rc = ibmvscsi_reset_crq_queue(&hostdata->queue, hostdata);
> @@ -2142,7 +2139,10 @@ static void ibmvscsi_do_work(struct ibmvscsi_host_data *hostdata)
> if (!rc)
> rc = ibmvscsi_send_crq(hostdata, 0xC001000000000000LL, 0);
> break;
> + case IBMVSCSI_HOST_ACTION_NONE:
> + case IBMVSCSI_HOST_ACTION_UNBLOCK:
> default:
> + rc = 0;
> break;
> }
>
>
> But then that makes me wonder if that's actually correct?
>
> If we get an action that we don't recognise should we just throw it away
> like that? (by doing hostdata->action = IBMVSCSI_HOST_ACTION_NONE). Tyrel?

However, because of this, I will hold off on v2 until Tyrel can give
some feedback.

Thanks,
Nathan