[PATCH v2] mm: Move MAP_SYNC to asm-generic/mman-common.h

[PATCH v2] mm: Move MAP_SYNC to asm-generic/mman-common.h

[Aneesh Kumar K.V]

This enables support for synchronous DAX fault on powerpc

The generic changes are added as part of
commit b6fb293f2497 ("mm: Define MAP_SYNC and VM_SYNC flags")

Without this, mmap returns EOPNOTSUPP for MAP_SYNC with MAP_SHARED_VALIDATE

Instead of adding MAP_SYNC with same value to
arch/powerpc/include/uapi/asm/mman.h, I am moving the #define to
asm-generic/mman-common.h. Two architectures using mman-common.h directly are
sparc and powerpc. We should be able to consloidate more #defines to
mman-common.h. That can be done as a separate patch.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
Changes from V1:
* Move #define to mman-common.h instead of powerpc specific mman.h change


 include/uapi/asm-generic/mman-common.h | 3 ++-
 include/uapi/asm-generic/mman.h        | 1 -
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/uapi/asm-generic/mman-common.h b/include/uapi/asm-generic/mman-common.h
index abd238d0f7a4..bea0278f65ab 100644
--- a/include/uapi/asm-generic/mman-common.h
+++ b/include/uapi/asm-generic/mman-common.h
@@ -25,7 +25,8 @@
 # define MAP_UNINITIALIZED 0x0		/* Don't support this flag */
 #endif
 
-/* 0x0100 - 0x80000 flags are defined in asm-generic/mman.h */
+/* 0x0100 - 0x40000 flags are defined in asm-generic/mman.h */
+#define MAP_SYNC		0x080000 /* perform synchronous page faults for the mapping */
 #define MAP_FIXED_NOREPLACE	0x100000	/* MAP_FIXED which doesn't unmap underlying mapping */
 
 /*
diff --git a/include/uapi/asm-generic/mman.h b/include/uapi/asm-generic/mman.h
index 653687d9771b..2dffcbf705b3 100644
--- a/include/uapi/asm-generic/mman.h
+++ b/include/uapi/asm-generic/mman.h
@@ -13,7 +13,6 @@
 #define MAP_NONBLOCK	0x10000		/* do not block on IO */
 #define MAP_STACK	0x20000		/* give out an address that is best suited for process/thread stacks */
 #define MAP_HUGETLB	0x40000		/* create a huge page mapping */
-#define MAP_SYNC	0x80000		/* perform synchronous page faults for the mapping */
 
 /* Bits [26:31] are reserved, see mman-common.h for MAP_HUGETLB usage */
 
-- 
2.21.0

Re: [PATCH v2] mm: Move MAP_SYNC to asm-generic/mman-common.h

[Jan Kara]

On Tue 28-05-19 14:41:20, Aneesh Kumar K.V wrote:
> This enables support for synchronous DAX fault on powerpc
> 
> The generic changes are added as part of
> commit b6fb293f2497 ("mm: Define MAP_SYNC and VM_SYNC flags")
> 
> Without this, mmap returns EOPNOTSUPP for MAP_SYNC with MAP_SHARED_VALIDATE
> 
> Instead of adding MAP_SYNC with same value to
> arch/powerpc/include/uapi/asm/mman.h, I am moving the #define to
> asm-generic/mman-common.h. Two architectures using mman-common.h directly are
> sparc and powerpc. We should be able to consloidate more #defines to
> mman-common.h. That can be done as a separate patch.
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>

Looks good to me FWIW (I don't have much experience with mmap flags and
their peculirarities). So feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
> Changes from V1:
> * Move #define to mman-common.h instead of powerpc specific mman.h change
> 
> 
>  include/uapi/asm-generic/mman-common.h | 3 ++-
>  include/uapi/asm-generic/mman.h        | 1 -
>  2 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/include/uapi/asm-generic/mman-common.h b/include/uapi/asm-generic/mman-common.h
> index abd238d0f7a4..bea0278f65ab 100644
> --- a/include/uapi/asm-generic/mman-common.h
> +++ b/include/uapi/asm-generic/mman-common.h
> @@ -25,7 +25,8 @@
>  # define MAP_UNINITIALIZED 0x0		/* Don't support this flag */
>  #endif
>  
> -/* 0x0100 - 0x80000 flags are defined in asm-generic/mman.h */
> +/* 0x0100 - 0x40000 flags are defined in asm-generic/mman.h */
> +#define MAP_SYNC		0x080000 /* perform synchronous page faults for the mapping */
>  #define MAP_FIXED_NOREPLACE	0x100000	/* MAP_FIXED which doesn't unmap underlying mapping */
>  
>  /*
> diff --git a/include/uapi/asm-generic/mman.h b/include/uapi/asm-generic/mman.h
> index 653687d9771b..2dffcbf705b3 100644
> --- a/include/uapi/asm-generic/mman.h
> +++ b/include/uapi/asm-generic/mman.h
> @@ -13,7 +13,6 @@
>  #define MAP_NONBLOCK	0x10000		/* do not block on IO */
>  #define MAP_STACK	0x20000		/* give out an address that is best suited for process/thread stacks */
>  #define MAP_HUGETLB	0x40000		/* create a huge page mapping */
> -#define MAP_SYNC	0x80000		/* perform synchronous page faults for the mapping */
>  
>  /* Bits [26:31] are reserved, see mman-common.h for MAP_HUGETLB usage */
>  
> -- 
> 2.21.0
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR