On Sun, Oct 17, 2021 at 9:41 PM Christoph Hellwig <hch@xxxxxx> wrote:
>
> Add a helper to perform the entire remapping for DAX accesses. This
> helper open codes bdev_dax_pgoff given that the alignment checks have
> already been done by the submitting file system and don't need to be
> repeated.
Looks good.
Mike, ack?
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> drivers/md/dm-linear.c | 49 +++++++++++++-----------------------------
> 1 file changed, 15 insertions(+), 34 deletions(-)
>
> diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
> index 32fbab11bf90c..bf03f73fd0f36 100644
> --- a/drivers/md/dm-linear.c
> +++ b/drivers/md/dm-linear.c
> @@ -164,63 +164,44 @@ static int linear_iterate_devices(struct dm_target *ti,
> }
>
> #if IS_ENABLED(CONFIG_FS_DAX)
> +static struct dax_device *linear_dax_pgoff(struct dm_target *ti, pgoff_t *pgoff)
> +{
> + struct linear_c *lc = ti->private;
> + sector_t sector = linear_map_sector(ti, *pgoff << PAGE_SECTORS_SHIFT);
> +
> + *pgoff = (get_start_sect(lc->dev->bdev) + sector) >> PAGE_SECTORS_SHIFT;
> + return lc->dev->dax_dev;
> +}
> +
> static long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
> long nr_pages, void **kaddr, pfn_t *pfn)
> {
> - long ret;
> - struct linear_c *lc = ti->private;
> - struct block_device *bdev = lc->dev->bdev;
> - struct dax_device *dax_dev = lc->dev->dax_dev;
> - sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
> -
> - dev_sector = linear_map_sector(ti, sector);
> - ret = bdev_dax_pgoff(bdev, dev_sector, nr_pages * PAGE_SIZE, &pgoff);
> - if (ret)
> - return ret;
> + struct dax_device *dax_dev = linear_dax_pgoff(ti, &pgoff);
> +
> return dax_direct_access(dax_dev, pgoff, nr_pages, kaddr, pfn);
> }
>
> static size_t linear_dax_copy_from_iter(struct dm_target *ti, pgoff_t pgoff,
> void *addr, size_t bytes, struct iov_iter *i)
> {
> - struct linear_c *lc = ti->private;
> - struct block_device *bdev = lc->dev->bdev;
> - struct dax_device *dax_dev = lc->dev->dax_dev;
> - sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
> + struct dax_device *dax_dev = linear_dax_pgoff(ti, &pgoff);
>
> - dev_sector = linear_map_sector(ti, sector);
> - if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(bytes, PAGE_SIZE), &pgoff))
> - return 0;
> return dax_copy_from_iter(dax_dev, pgoff, addr, bytes, i);
> }
>
> static size_t linear_dax_copy_to_iter(struct dm_target *ti, pgoff_t pgoff,
> void *addr, size_t bytes, struct iov_iter *i)
> {
> - struct linear_c *lc = ti->private;
> - struct block_device *bdev = lc->dev->bdev;
> - struct dax_device *dax_dev = lc->dev->dax_dev;
> - sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
> + struct dax_device *dax_dev = linear_dax_pgoff(ti, &pgoff);
>
> - dev_sector = linear_map_sector(ti, sector);
> - if (bdev_dax_pgoff(bdev, dev_sector, ALIGN(bytes, PAGE_SIZE), &pgoff))
> - return 0;
> return dax_copy_to_iter(dax_dev, pgoff, addr, bytes, i);
> }
>
> static int linear_dax_zero_page_range(struct dm_target *ti, pgoff_t pgoff,
> size_t nr_pages)
> {
> - int ret;
> - struct linear_c *lc = ti->private;
> - struct block_device *bdev = lc->dev->bdev;
> - struct dax_device *dax_dev = lc->dev->dax_dev;
> - sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
> -
> - dev_sector = linear_map_sector(ti, sector);
> - ret = bdev_dax_pgoff(bdev, dev_sector, nr_pages << PAGE_SHIFT, &pgoff);
> - if (ret)
> - return ret;
> + struct dax_device *dax_dev = linear_dax_pgoff(ti, &pgoff);
> +
> return dax_zero_page_range(dax_dev, pgoff, nr_pages);
> }
>
> --
> 2.30.2
>
