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References: <20211018044054.1779424-1-hch@lst.de> <20211018044054.1779424-2-hch@lst.de>
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From:   Dan Williams <dan.j.williams@intel.com>
Date:   Wed, 27 Oct 2021 13:53:21 -0700
Message-ID: <CAPcyv4hrEPizMOH-XhCqh=23EJDG=W6VwvQ1pVstfe-Jm-AsiQ@mail.gmail.com>
Subject: Re: [PATCH 01/11] dm: make the DAX support dependend on CONFIG_FS_DAX
To:     Christoph Hellwig <hch@lst.de>, Mike Snitzer <snitzer@redhat.com>
Cc:     Ira Weiny <ira.weiny@intel.com>,
        device-mapper development <dm-devel@redhat.com>,
        linux-xfs <linux-xfs@vger.kernel.org>,
        Linux NVDIMM <nvdimm@lists.linux.dev>,
        linux-s390 <linux-s390@vger.kernel.org>,
        linux-fsdevel <linux-fsdevel@vger.kernel.org>,
        linux-erofs@lists.ozlabs.org,
        linux-ext4 <linux-ext4@vger.kernel.org>,
        virtualization@lists.linux-foundation.org
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On Sun, Oct 17, 2021 at 9:41 PM Christoph Hellwig <hch@lst.de> wrote:
>
> The device mapper DAX support is all hanging off a block device and thus
> can't be used with device dax.  Make it depend on CONFIG_FS_DAX instead
> of CONFIG_DAX_DRIVER.  This also means that bdev_dax_pgoff only needs to
> be built under CONFIG_FS_DAX now.

Looks good.

Mike, can I get an ack to take this through nvdimm.git? (you'll likely
see me repeat this question on subsequent patches in this series).

>
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  drivers/dax/super.c        | 6 ++----
>  drivers/md/dm-linear.c     | 2 +-
>  drivers/md/dm-log-writes.c | 2 +-
>  drivers/md/dm-stripe.c     | 2 +-
>  drivers/md/dm-writecache.c | 2 +-
>  drivers/md/dm.c            | 2 +-
>  6 files changed, 7 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/dax/super.c b/drivers/dax/super.c
> index b882cf8106ea3..e20d0cef10a18 100644
> --- a/drivers/dax/super.c
> +++ b/drivers/dax/super.c
> @@ -63,7 +63,7 @@ static int dax_host_hash(const char *host)
>         return hashlen_hash(hashlen_string("DAX", host)) % DAX_HASH_SIZE;
>  }
>
> -#ifdef CONFIG_BLOCK
> +#if defined(CONFIG_BLOCK) && defined(CONFIG_FS_DAX)
>  #include <linux/blkdev.h>
>
>  int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size,
> @@ -80,7 +80,6 @@ int bdev_dax_pgoff(struct block_device *bdev, sector_t sector, size_t size,
>  }
>  EXPORT_SYMBOL(bdev_dax_pgoff);
>
> -#if IS_ENABLED(CONFIG_FS_DAX)
>  /**
>   * dax_get_by_host() - temporary lookup mechanism for filesystem-dax
>   * @host: alternate name for the device registered by a dax driver
> @@ -219,8 +218,7 @@ bool dax_supported(struct dax_device *dax_dev, struct block_device *bdev,
>         return ret;
>  }
>  EXPORT_SYMBOL_GPL(dax_supported);
> -#endif /* CONFIG_FS_DAX */
> -#endif /* CONFIG_BLOCK */
> +#endif /* CONFIG_BLOCK && CONFIG_FS_DAX */
>
>  enum dax_device_flags {
>         /* !alive + rcu grace period == no new operations / mappings */
> diff --git a/drivers/md/dm-linear.c b/drivers/md/dm-linear.c
> index 679b4c0a2eea1..32fbab11bf90c 100644
> --- a/drivers/md/dm-linear.c
> +++ b/drivers/md/dm-linear.c
> @@ -163,7 +163,7 @@ static int linear_iterate_devices(struct dm_target *ti,
>         return fn(ti, lc->dev, lc->start, ti->len, data);
>  }
>
> -#if IS_ENABLED(CONFIG_DAX_DRIVER)
> +#if IS_ENABLED(CONFIG_FS_DAX)
>  static long linear_dax_direct_access(struct dm_target *ti, pgoff_t pgoff,
>                 long nr_pages, void **kaddr, pfn_t *pfn)
>  {
> diff --git a/drivers/md/dm-log-writes.c b/drivers/md/dm-log-writes.c
> index d93a4db235124..6d694526881d0 100644
> --- a/drivers/md/dm-log-writes.c
> +++ b/drivers/md/dm-log-writes.c
> @@ -903,7 +903,7 @@ static void log_writes_io_hints(struct dm_target *ti, struct queue_limits *limit
>         limits->io_min = limits->physical_block_size;
>  }
>
> -#if IS_ENABLED(CONFIG_DAX_DRIVER)
> +#if IS_ENABLED(CONFIG_FS_DAX)
>  static int log_dax(struct log_writes_c *lc, sector_t sector, size_t bytes,
>                    struct iov_iter *i)
>  {
> diff --git a/drivers/md/dm-stripe.c b/drivers/md/dm-stripe.c
> index 6660b6b53d5bf..f084607220293 100644
> --- a/drivers/md/dm-stripe.c
> +++ b/drivers/md/dm-stripe.c
> @@ -300,7 +300,7 @@ static int stripe_map(struct dm_target *ti, struct bio *bio)
>         return DM_MAPIO_REMAPPED;
>  }
>
> -#if IS_ENABLED(CONFIG_DAX_DRIVER)
> +#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)
>  {
> diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
> index 18320444fb0a9..4c3a6e33604d3 100644
> --- a/drivers/md/dm-writecache.c
> +++ b/drivers/md/dm-writecache.c
> @@ -38,7 +38,7 @@
>  #define BITMAP_GRANULARITY     PAGE_SIZE
>  #endif
>
> -#if IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API) && IS_ENABLED(CONFIG_DAX_DRIVER)
> +#if IS_ENABLED(CONFIG_ARCH_HAS_PMEM_API) && IS_ENABLED(CONFIG_FS_DAX)
>  #define DM_WRITECACHE_HAS_PMEM
>  #endif
>
> diff --git a/drivers/md/dm.c b/drivers/md/dm.c
> index 7870e6460633f..79737aee516b1 100644
> --- a/drivers/md/dm.c
> +++ b/drivers/md/dm.c
> @@ -1783,7 +1783,7 @@ static struct mapped_device *alloc_dev(int minor)
>         md->disk->private_data = md;
>         sprintf(md->disk->disk_name, "dm-%d", minor);
>
> -       if (IS_ENABLED(CONFIG_DAX_DRIVER)) {
> +       if (IS_ENABLED(CONFIG_FS_DAX)) {
>                 md->dax_dev = alloc_dax(md, md->disk->disk_name,
>                                         &dm_dax_ops, 0);
>                 if (IS_ERR(md->dax_dev))
> --
> 2.30.2
>