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Date:   Wed, 2 Feb 2022 05:28:43 -0800
From:   Christoph Hellwig <hch@infradead.org>
To:     Jane Chu <jane.chu@oracle.com>
Cc:     david@fromorbit.com, djwong@kernel.org, dan.j.williams@intel.com,
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        linux-fsdevel@vger.kernel.org, nvdimm@lists.linux.dev,
        linux-kernel@vger.kernel.org, linux-xfs@vger.kernel.org
Subject: Re: [PATCH v5 7/7] pmem: fix pmem_do_write() avoid writing to 'np'
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References: <20220128213150.1333552-1-jane.chu@oracle.com>
 <20220128213150.1333552-8-jane.chu@oracle.com>
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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;