[PATCH 10/11] dm-stripe: add a stripe_dax_pgoff helper

[Christoph Hellwig]

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 
---
 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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Re: [PATCH 10/11] dm-stripe: add a stripe_dax_pgoff helper

[Dan Williams]

On Sun, Oct 17, 2021 at 9:41 PM Christoph Hellwig  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 
> ---
>  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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Re: [PATCH 10/11] dm-stripe: add a stripe_dax_pgoff helper

[Mike Snitzer]

On Wed, Oct 27 2021 at  9:41P -0400,
Dan Williams  wrote:

> On Sun, Oct 17, 2021 at 9:41 PM Christoph Hellwig  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?

Acked-by: Mike Snitzer 

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