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.
Again, looks good. Kind of embarrassing when the open-coded version is
less LOC than using the helper.
Mike, ack?
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> drivers/md/dm-stripe.c | 63 ++++++++++--------------------------------
> 1 file changed, 15 insertions(+), 48 deletions(-)
>
> diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c
> index f084607220293..50dba3f39274c 100644
> --- a/drivers/md/dm-stripe.c
> +++ b/drivers/md/dm-stripe.c
> @@ -301,83 +301,50 @@ static int stripe_map(struct dm_target *ti, struct bio *bio)
> }
>
> #if IS_ENABLED(CONFIG_FS_DAX)
> -static long stripe_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
> - long nr_pages, void **kaddr, pfn_t *pfn)
> +static struct dax_device *stripe_dax_pgoff(struct dm_target *ti, pgoff_t *pgoff)
> {
> - sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
> struct stripe_c *sc = ti->private;
> - struct dax_device *dax_dev;
> struct block_device *bdev;
> + sector_t dev_sector;
> uint32_t stripe;
> - long ret;
>
> - stripe_map_sector(sc, sector, &stripe, &dev_sector);
> + stripe_map_sector(sc, *pgoff * PAGE_SECTORS, &stripe, &dev_sector);
> dev_sector += sc->stripe[stripe].physical_start;
> - dax_dev = sc->stripe[stripe].dev->dax_dev;
> bdev = sc->stripe[stripe].dev->bdev;
>
> - ret = bdev_dax_pgoff(bdev, dev_sector, nr_pages * PAGE_SIZE, &pgoff);
> - if (ret)
> - return ret;
> + *pgoff = (get_start_sect(bdev) + dev_sector) >> PAGE_SECTORS_SHIFT;
> + return sc->stripe[stripe].dev->dax_dev;
> +}
> +
> +static long stripe_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
> + long nr_pages, void **kaddr, pfn_t *pfn)
> +{
> + struct dax_device *dax_dev = stripe_dax_pgoff(ti, &pgoff);
> +
> return dax_direct_access(dax_dev, pgoff, nr_pages, kaddr, pfn);
> }
>
> static size_t stripe_dax_copy_from_iter(struct dm_target *ti, pgoff_t pgoff,
> void *addr, size_t bytes, struct iov_iter *i)
> {
> - sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
> - struct stripe_c *sc = ti->private;
> - struct dax_device *dax_dev;
> - struct block_device *bdev;
> - uint32_t stripe;
> -
> - stripe_map_sector(sc, sector, &stripe, &dev_sector);
> - dev_sector += sc->stripe[stripe].physical_start;
> - dax_dev = sc->stripe[stripe].dev->dax_dev;
> - bdev = sc->stripe[stripe].dev->bdev;
> + struct dax_device *dax_dev = stripe_dax_pgoff(ti, &pgoff);
>
> - 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 stripe_dax_copy_to_iter(struct dm_target *ti, pgoff_t pgoff,
> void *addr, size_t bytes, struct iov_iter *i)
> {
> - sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
> - struct stripe_c *sc = ti->private;
> - struct dax_device *dax_dev;
> - struct block_device *bdev;
> - uint32_t stripe;
> -
> - stripe_map_sector(sc, sector, &stripe, &dev_sector);
> - dev_sector += sc->stripe[stripe].physical_start;
> - dax_dev = sc->stripe[stripe].dev->dax_dev;
> - bdev = sc->stripe[stripe].dev->bdev;
> + struct dax_device *dax_dev = stripe_dax_pgoff(ti, &pgoff);
>
> - 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 stripe_dax_zero_page_range(struct dm_target *ti, pgoff_t pgoff,
> size_t nr_pages)
> {
> - int ret;
> - sector_t dev_sector, sector = pgoff * PAGE_SECTORS;
> - struct stripe_c *sc = ti->private;
> - struct dax_device *dax_dev;
> - struct block_device *bdev;
> - uint32_t stripe;
> + struct dax_device *dax_dev = stripe_dax_pgoff(ti, &pgoff);
>
> - stripe_map_sector(sc, sector, &stripe, &dev_sector);
> - dev_sector += sc->stripe[stripe].physical_start;
> - dax_dev = sc->stripe[stripe].dev->dax_dev;
> - bdev = sc->stripe[stripe].dev->bdev;
> -
> - ret = bdev_dax_pgoff(bdev, dev_sector, nr_pages << PAGE_SHIFT, &pgoff);
> - if (ret)
> - return ret;
> return dax_zero_page_range(dax_dev, pgoff, nr_pages);
> }
>
> --
> 2.30.2
>
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