[PATCH 11/29] dm-stripe: add a stripe_dax_pgoff helper

Christoph Hellwig
2021-11-09T08:33:47Z

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.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Mike Snitzer <snitzer@redhat.com>
---
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