Re: [PATCH v2 2/5] dax: fix dax_mapping() definition in the FS_DAX=n + DEV_DAX=y case

[Jan Kara]

On Thu 22-02-18 23:17:51, Dan Williams wrote:
> An address_space will only have dax exceptional entries when FS_DAX is
> enabled. The current reliance on S_DAX causes compile failures when
> S_DAX is defined for DEV_DAX, but FS_DAX is disabled. Make dax_mapping()
> always return false so that mm/truncate.c drops its link time
> dependencies on fs/dax.c.
> 
> Cc: Alexander Viro 
> Cc: linux-fsde...@vger.kernel.org
> Cc: Christoph Hellwig 
> Cc: Jan Kara 
> Cc: 
> Reported-by: kbuild test robot 
> Fixes: dee410792419 ("/dev/dax, core: file operations and dax-mmap")
> Signed-off-by: Dan Williams 

Looks good. You can add:

Reviewed-by: Jan Kara 

Honza

> ---
>  include/linux/dax.h |9 ++---
>  1 file changed, 6 insertions(+), 3 deletions(-)
> 
> diff --git a/include/linux/dax.h b/include/linux/dax.h
> index 0185ecdae135..62e8cf7eb566 100644
> --- a/include/linux/dax.h
> +++ b/include/linux/dax.h
> @@ -107,6 +107,10 @@ int dax_invalidate_mapping_entry_sync(struct 
> address_space *mapping,
>  int __dax_zero_page_range(struct block_device *bdev,
>   struct dax_device *dax_dev, sector_t sector,
>   unsigned int offset, unsigned int length);
> +static inline bool dax_mapping(struct address_space *mapping)
> +{
> + return mapping->host && IS_DAX(mapping->host);
> +}
>  #else
>  static inline int __dax_zero_page_range(struct block_device *bdev,
>   struct dax_device *dax_dev, sector_t sector,
> @@ -114,12 +118,11 @@ static inline int __dax_zero_page_range(struct 
> block_device *bdev,
>  {
>   return -ENXIO;
>  }
> -#endif
> -
>  static inline bool dax_mapping(struct address_space *mapping)
>  {
> - return mapping->host && IS_DAX(mapping->host);
> + return false;
>  }
> +#endif
>  
>  struct writeback_control;
>  int dax_writeback_mapping_range(struct address_space *mapping,
> 
-- 
Jan Kara 
SUSE Labs, CR

[PATCH v2 2/5] dax: fix dax_mapping() definition in the FS_DAX=n + DEV_DAX=y case

[Dan Williams]

An address_space will only have dax exceptional entries when FS_DAX is
enabled. The current reliance on S_DAX causes compile failures when
S_DAX is defined for DEV_DAX, but FS_DAX is disabled. Make dax_mapping()
always return false so that mm/truncate.c drops its link time
dependencies on fs/dax.c.

Cc: Alexander Viro 
Cc: linux-fsde...@vger.kernel.org
Cc: Christoph Hellwig 
Cc: Jan Kara 
Cc: 
Reported-by: kbuild test robot 
Fixes: dee410792419 ("/dev/dax, core: file operations and dax-mmap")
Signed-off-by: Dan Williams 
---
 include/linux/dax.h |9 ++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/include/linux/dax.h b/include/linux/dax.h
index 0185ecdae135..62e8cf7eb566 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -107,6 +107,10 @@ int dax_invalidate_mapping_entry_sync(struct address_space 
*mapping,
 int __dax_zero_page_range(struct block_device *bdev,
struct dax_device *dax_dev, sector_t sector,
unsigned int offset, unsigned int length);
+static inline bool dax_mapping(struct address_space *mapping)
+{
+   return mapping->host && IS_DAX(mapping->host);
+}
 #else
 static inline int __dax_zero_page_range(struct block_device *bdev,
struct dax_device *dax_dev, sector_t sector,
@@ -114,12 +118,11 @@ static inline int __dax_zero_page_range(struct 
block_device *bdev,
 {
return -ENXIO;
 }
-#endif
-
 static inline bool dax_mapping(struct address_space *mapping)
 {
-   return mapping->host && IS_DAX(mapping->host);
+   return false;
 }
+#endif
 
 struct writeback_control;
 int dax_writeback_mapping_range(struct address_space *mapping,