[PATCH 10/29] dm-log-writes: add a log_writes_dax_pgoff helper

Christoph Hellwig
2021-11-09T08:33:45Z

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-log-writes.c | 42 +++++++++++++++-----------------------
1 file changed, 17 insertions(+), 25 deletions(-)

diff --git a/drivers/md/dm-log-writes.c b/drivers/md/dm-log-writes.c
index 524bc536922eb..df3cd78223fb2 100644
--- a/drivers/md/dm-log-writes.c
+++ b/drivers/md/dm-log-writes.c
@@ -949,17 +949,21 @@ static int log_dax(struct log_writes_c *lc, sector_t sector, size_t bytes,
return 0;
}

+static struct dax_device *log_writes_dax_pgoff(struct dm_target *ti,
+ pgoff_t *pgoff)
+{
+ struct log_writes_c *lc = ti->private;
+
+ *pgoff += (get_start_sect(lc->dev->bdev) >> PAGE_SECTORS_SHIFT);
+ return lc->dev->dax_dev;
+}
+
static long log_writes_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
long nr_pages, void **kaddr, pfn_t *pfn)
{
- struct log_writes_c *lc = ti->private;
- sector_t sector = pgoff * PAGE_SECTORS;
- int ret;
+ struct dax_device *dax_dev = log_writes_dax_pgoff(ti, &pgoff);

- ret = bdev_dax_pgoff(lc->dev->bdev, sector, nr_pages * PAGE_SIZE, &pgoff);
- if (ret)
- return ret;
- return dax_direct_access(lc->dev->dax_dev, pgoff, nr_pages, kaddr, pfn);
+ return dax_direct_access(dax_dev, pgoff, nr_pages, kaddr, pfn);
}

static size_t log_writes_dax_copy_from_iter(struct dm_target *ti,
@@ -968,11 +972,9 @@ static size_t log_writes_dax_copy_from_iter(struct dm_target *ti,
{
struct log_writes_c *lc = ti->private;
sector_t sector = pgoff * PAGE_SECTORS;
+ struct dax_device *dax_dev = log_writes_dax_pgoff(ti, &pgoff);
int err;

- if (bdev_dax_pgoff(lc->dev->bdev, sector, ALIGN(bytes, PAGE_SIZE), &pgoff))
- return 0;
-
/* Don't bother doing anything if logging has been disabled */
if (!lc->logging_enabled)
goto dax_copy;
@@ -983,34 +985,24 @@ static size_t log_writes_dax_copy_from_iter(struct dm_target *ti,
return 0;
}
dax_copy:
- return dax_copy_from_iter(lc->dev->dax_dev, pgoff, addr, bytes, i);
+ return dax_copy_from_iter(dax_dev, pgoff, addr, bytes, i);
}

static size_t log_writes_dax_copy_to_iter(struct dm_target *ti,
pgoff_t pgoff, void *addr, size_t bytes,
struct iov_iter *i)
{
- struct log_writes_c *lc = ti->private;
- sector_t sector = pgoff * PAGE_SECTORS;
+ struct dax_device *dax_dev = log_writes_dax_pgoff(ti, &pgoff);

- if (bdev_dax_pgoff(lc->dev->bdev, sector, ALIGN(bytes, PAGE_SIZE), &pgoff))
- return 0;
- return dax_copy_to_iter(lc->dev->dax_dev, pgoff, addr, bytes, i);
+ return dax_copy_to_iter(dax_dev, pgoff, addr, bytes, i);
}

static int log_writes_dax_zero_page_range(struct dm_target *ti, pgoff_t pgoff,
size_t nr_pages)
{
- int ret;
- struct log_writes_c *lc = ti->private;
- sector_t sector = pgoff * PAGE_SECTORS;
+ struct dax_device *dax_dev = log_writes_dax_pgoff(ti, &pgoff);

- ret = bdev_dax_pgoff(lc->dev->bdev, sector, nr_pages << PAGE_SHIFT,
- &pgoff);
- if (ret)
- return ret;
- return dax_zero_page_range(lc->dev->dax_dev, pgoff,
- nr_pages << PAGE_SHIFT);
+ return dax_zero_page_range(dax_dev, pgoff, nr_pages << PAGE_SHIFT);
}

#else
--
2.30.2