Re: [PATCH] scsi: lpfc: use memcpy_toio instead of writeq

[James Smart]

About to post a patch to fix. Rather than fidgeting with the copy 
routine, I want to go back to what we originally proposed - writeq() on 
64bit, writel() on 32-bit.

-- james


On 2/23/2018 1:02 PM, Arnd Bergmann wrote:
> On Fri, Feb 23, 2018 at 4:36 PM, Arnd Bergmann <arnd@xxxxxxxx> wrote:
> > @@ -138,12 +137,10 @@ lpfc_sli4_wq_put(struct lpfc_queue *q, union lpfc_wqe *wqe)
> >          if (q->phba->sli3_options & LPFC_SLI4_PHWQ_ENABLED)
> >                  bf_set(wqe_wqid, &wqe->generic.wqe_com, q->queue_id);
> >          lpfc_sli_pcimem_bcopy(wqe, temp_wqe, q->entry_size);
> > -       if (q->dpp_enable && q->phba->cfg_enable_dpp) {
> > +       if (q->dpp_enable && q->phba->cfg_enable_dpp)
> >                  /* write to DPP aperture taking advatage of Combined Writes */
> > -               tmp = (uint8_t *)wqe;
> > -               for (i = 0; i < q->entry_size; i += sizeof(uint64_t))
> > -                       writeq(*((uint64_t *)(tmp + i)), q->dpp_regaddr + i);
> > -       }
> > +               memcpy_toio(tmp, q->dpp_regaddr, q->entry_size);
> > +
> >          /* ensure WQE bcopy and DPP flushed before doorbell write */
> >          wmb();
> Not sure where we are with the question of whether memcpy_toio
> is a good replacement or not, but further build testing showed that
> my patch was completely broken in more than one way:
>
> I mixed up the source and destination arguments, and I used
> the uninitialized 'tmp' instead of 'wqe'. Don't try this patch.
>
>         Arnd