Re: [PATCH v5 7/7] pmem: fix pmem_do_write() avoid writing to 'np' page

[Christoph Hellwig]

On Fri, Jan 28, 2022 at 02:31:50PM -0700, Jane Chu wrote:
> +     if (!bad_pmem) {
>               write_pmem(pmem_addr, page, page_off, len);
> +     } else {
> +             rc = pmem_clear_poison(pmem, pmem_off, len);
> +             if (rc == BLK_STS_OK)
> +                     write_pmem(pmem_addr, page, page_off, len);
> +             else
> +                     pr_warn("%s: failed to clear poison\n",
> +                             __func__);

This warning probably needs ratelimiting.

Also this flow looks a little odd.  I'd redo the whole function with a
clear bad_mem case:

        if (unlikely(is_bad_pmem(&pmem->bb, sector, len))) {
                blk_status_t rc = pmem_clear_poison(pmem, pmem_off, len);

                if (rc != BLK_STS_OK) {
                        pr_warn("%s: failed to clear poison\n", __func__);
                        return rc;
                }
        }
        flush_dcache_page(page);
        write_pmem(pmem_addr, page, page_off, len);
        return BLK_STS_OK;