> + /*
> + * There are no users as of now. Once users are there, fix dm code
> + * to be able to split a long range across targets.
> + */
This comment confused me. I think this wants to say something like:
/*
* There are now callers that want to zero across a page boundary as of
* now. Once there are users this check can be removed after the
* device mapper code has been updated to split ranges across targets.
*/
> +static int pmem_dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
> + unsigned int offset, size_t len)
> +{
> + int rc = 0;
> + phys_addr_t phys_pos = pgoff * PAGE_SIZE + offset;
Any reason not to pass a phys_addr_t in the calling convention for the
method and maybe also for dax_zero_page_range itself?
> + sector_start = ALIGN(phys_pos, 512)/512;
> + sector_end = ALIGN_DOWN(phys_pos + bytes, 512)/512;
Missing whitespaces. Also this could use DIV_ROUND_UP and
DIV_ROUND_DOWN.
> + if (sector_end > sector_start)
> + nr_sectors = sector_end - sector_start;
> +
> + if (nr_sectors &&
> + unlikely(is_bad_pmem(&pmem->bb, sector_start,
> + nr_sectors * 512)))
> + bad_pmem = true;
How could nr_sectors be zero?
> + write_pmem(pmem_addr, page, 0, bytes);
> + if (unlikely(bad_pmem)) {
> + /*
> + * Pass block aligned offset and length. That seems
> + * to work as of now. Other finer grained alignment
> + * cases can be addressed later if need be.
> + */
> + rc = pmem_clear_poison(pmem, ALIGN(pmem_off, 512),
> + nr_sectors * 512);
> + write_pmem(pmem_addr, page, 0, bytes);
> + }
This code largerly duplicates the write side of pmem_do_bvec. I
think it might make sense to split pmem_do_bvec into a read and a write
side as a prep patch, and then reuse the write side here.
> +int generic_dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
> + unsigned int offset, size_t len);
This should probably go into a separare are of the header and have
comment about being a section for generic helpers for drivers.
