Re: [RFC PATCH v2 3/3] mm: make generic pXd_addr_end() macros inline functions

2020-09-08 Thread Alexander Gordeev 
On Tue, Sep 08, 2020 at 07:19:38AM +0200, Christophe Leroy wrote:

[...]

> >diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
> >index 67ebc22cf83d..d9e7d16c2263 100644
> >--- a/include/linux/pgtable.h
> >+++ b/include/linux/pgtable.h
> >@@ -656,31 +656,35 @@ static inline int arch_unmap_one(struct mm_struct *mm,
> >   */
> >  #ifndef pgd_addr_end
> >-#define pgd_addr_end(pgd, addr, end)
> >\
> >-({  unsigned long __boundary = ((addr) + PGDIR_SIZE) & PGDIR_MASK;  \
> >-(__boundary - 1 < (end) - 1)? __boundary: (end);\
> >-})
> >+#define pgd_addr_end pgd_addr_end
> 
> I think that #define is pointless, usually there is no such #define
> for the default case.

Default pgd_addr_end() gets overriden on s390 (arch/s390/include/asm/pgtable.h):

#define pgd_addr_end pgd_addr_end
static inline unsigned long pgd_addr_end(pgd_t pgd, unsigned long addr, 
unsigned long end)
{
return rste_addr_end_folded(pgd_val(pgd), addr, end);
}

> >+static inline unsigned long pgd_addr_end(pgd_t pgd, unsigned long addr, 
> >unsigned long end)
> >+{   unsigned long __boundary = (addr + PGDIR_SIZE) & PGDIR_MASK;
> >+return (__boundary - 1 < end - 1) ? __boundary : end;
> >+}

Re: [RFC PATCH v2 3/3] mm: make generic pXd_addr_end() macros inline functions

2020-09-08 Thread Christophe Leroy 




Le 08/09/2020 à 17:48, Alexander Gordeev a écrit :

On Tue, Sep 08, 2020 at 07:19:38AM +0200, Christophe Leroy wrote:

[...]


diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 67ebc22cf83d..d9e7d16c2263 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -656,31 +656,35 @@ static inline int arch_unmap_one(struct mm_struct *mm,
   */
  #ifndef pgd_addr_end
-#define pgd_addr_end(pgd, addr, end)   \
-({ unsigned long __boundary = ((addr) + PGDIR_SIZE) & PGDIR_MASK;  \
-   (__boundary - 1 < (end) - 1)? __boundary: (end); \
-})
+#define pgd_addr_end pgd_addr_end


I think that #define is pointless, usually there is no such #define
for the default case.


Default pgd_addr_end() gets overriden on s390 (arch/s390/include/asm/pgtable.h):

#define pgd_addr_end pgd_addr_end
static inline unsigned long pgd_addr_end(pgd_t pgd, unsigned long addr, 
unsigned long end)
{
return rste_addr_end_folded(pgd_val(pgd), addr, end);
}


Yes, there in s390 the #define is needed to hit the #ifndef pgd_addr_end 
that's in include/linux/pgtable.h


But in include/linux/pgtable.h, there is no need of an #define 
pgd_addr_end pgd_addr_end I think





+static inline unsigned long pgd_addr_end(pgd_t pgd, unsigned long addr, 
unsigned long end)
+{  unsigned long __boundary = (addr + PGDIR_SIZE) & PGDIR_MASK;
+   return (__boundary - 1 < end - 1) ? __boundary : end;
+}



Christophe

Re: [RFC PATCH v2 3/3] mm: make generic pXd_addr_end() macros inline functions

2020-09-07 Thread Christophe Leroy 




Le 07/09/2020 à 20:00, Gerald Schaefer a écrit :

From: Alexander Gordeev 

Since pXd_addr_end() macros take pXd page-table entry as a
parameter it makes sense to check the entry type on compile.
Even though most archs do not make use of page-table entries
in pXd_addr_end() calls, checking the type in traversal code
paths could help to avoid subtle bugs.

Signed-off-by: Alexander Gordeev 
Signed-off-by: Gerald Schaefer 
---
  include/linux/pgtable.h | 36 
  1 file changed, 20 insertions(+), 16 deletions(-)

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 67ebc22cf83d..d9e7d16c2263 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -656,31 +656,35 @@ static inline int arch_unmap_one(struct mm_struct *mm,
   */
  
  #ifndef pgd_addr_end

-#define pgd_addr_end(pgd, addr, end)   \
-({ unsigned long __boundary = ((addr) + PGDIR_SIZE) & PGDIR_MASK;  \
-   (__boundary - 1 < (end) - 1)? __boundary: (end); \
-})
+#define pgd_addr_end pgd_addr_end


I think that #define is pointless, usually there is no such #define for 
the default case.



+static inline unsigned long pgd_addr_end(pgd_t pgd, unsigned long addr, 
unsigned long end)
+{  unsigned long __boundary = (addr + PGDIR_SIZE) & PGDIR_MASK;
+   return (__boundary - 1 < end - 1) ? __boundary : end;
+}


Please use the standard layout, ie entry { and exit } alone on their 
line, and space between local vars declaration and the rest.


Also remove the leading __ in front of var names as it's not needed once 
it is not macros anymore.


f_name()
{
some_local_var;

do_something();
}


  #endif
  
  #ifndef p4d_addr_end

-#define p4d_addr_end(p4d, addr, end)   \
-({ unsigned long __boundary = ((addr) + P4D_SIZE) & P4D_MASK;  \
-   (__boundary - 1 < (end) - 1)? __boundary: (end); \
-})
+#define p4d_addr_end p4d_addr_end
+static inline unsigned long p4d_addr_end(p4d_t p4d, unsigned long addr, 
unsigned long end)
+{  unsigned long __boundary = (addr + P4D_SIZE) & P4D_MASK;
+   return (__boundary - 1 < end - 1) ? __boundary : end;
+}
  #endif
  
  #ifndef pud_addr_end

-#define pud_addr_end(pud, addr, end)   \
-({ unsigned long __boundary = ((addr) + PUD_SIZE) & PUD_MASK;  \
-   (__boundary - 1 < (end) - 1)? __boundary: (end); \
-})
+#define pud_addr_end pud_addr_end
+static inline unsigned long pud_addr_end(pud_t pud, unsigned long addr, 
unsigned long end)
+{  unsigned long __boundary = (addr + PUD_SIZE) & PUD_MASK;
+   return (__boundary - 1 < end - 1) ? __boundary : end;
+}
  #endif
  
  #ifndef pmd_addr_end

-#define pmd_addr_end(pmd, addr, end)   \
-({ unsigned long __boundary = ((addr) + PMD_SIZE) & PMD_MASK;  \
-   (__boundary - 1 < (end) - 1)? __boundary: (end); \
-})
+#define pmd_addr_end pmd_addr_end
+static inline unsigned long pmd_addr_end(pmd_t pmd, unsigned long addr, 
unsigned long end)
+{  unsigned long __boundary = (addr + PMD_SIZE) & PMD_MASK;
+   return (__boundary - 1 < end - 1) ? __boundary : end;
+}
  #endif
  
  /*

Re: [RFC PATCH v2 3/3] mm: make generic pXd_addr_end() macros inline functions

2020-09-07 Thread Mike Rapoport 
Hi,

Some style comments below.

On Mon, Sep 07, 2020 at 08:00:58PM +0200, Gerald Schaefer wrote:
> From: Alexander Gordeev 
> 
> Since pXd_addr_end() macros take pXd page-table entry as a
> parameter it makes sense to check the entry type on compile.
> Even though most archs do not make use of page-table entries
> in pXd_addr_end() calls, checking the type in traversal code
> paths could help to avoid subtle bugs.
> 
> Signed-off-by: Alexander Gordeev 
> Signed-off-by: Gerald Schaefer 
> ---
>  include/linux/pgtable.h | 36 
>  1 file changed, 20 insertions(+), 16 deletions(-)
> 
> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
> index 67ebc22cf83d..d9e7d16c2263 100644
> --- a/include/linux/pgtable.h
> +++ b/include/linux/pgtable.h
> @@ -656,31 +656,35 @@ static inline int arch_unmap_one(struct mm_struct *mm,
>   */
>  
>  #ifndef pgd_addr_end
> -#define pgd_addr_end(pgd, addr, end) \
> -({   unsigned long __boundary = ((addr) + PGDIR_SIZE) & PGDIR_MASK;  \
> - (__boundary - 1 < (end) - 1)? __boundary: (end);\
> -})
> +#define pgd_addr_end pgd_addr_end
> +static inline unsigned long pgd_addr_end(pgd_t pgd, unsigned long addr, 
> unsigned long end)
> +{unsigned long __boundary = (addr + PGDIR_SIZE) & PGDIR_MASK;

The code should be on a separate line from the curly brace.
Besides, since this is not a macro anymore, I think it would be nicer to
use 'boundary' without underscores.
This applies to the changes below as well.

> + return (__boundary - 1 < end - 1) ? __boundary : end;
> +}
>  #endif
>  
>  #ifndef p4d_addr_end
> -#define p4d_addr_end(p4d, addr, end) \
> -({   unsigned long __boundary = ((addr) + P4D_SIZE) & P4D_MASK;  \
> - (__boundary - 1 < (end) - 1)? __boundary: (end);\
> -})
> +#define p4d_addr_end p4d_addr_end
> +static inline unsigned long p4d_addr_end(p4d_t p4d, unsigned long addr, 
> unsigned long end)
> +{unsigned long __boundary = (addr + P4D_SIZE) & P4D_MASK;
> + return (__boundary - 1 < end - 1) ? __boundary : end;
> +}
>  #endif
>  
>  #ifndef pud_addr_end
> -#define pud_addr_end(pud, addr, end) \
> -({   unsigned long __boundary = ((addr) + PUD_SIZE) & PUD_MASK;  \
> - (__boundary - 1 < (end) - 1)? __boundary: (end);\
> -})
> +#define pud_addr_end pud_addr_end
> +static inline unsigned long pud_addr_end(pud_t pud, unsigned long addr, 
> unsigned long end)
> +{unsigned long __boundary = (addr + PUD_SIZE) & PUD_MASK;
> + return (__boundary - 1 < end - 1) ? __boundary : end;
> +}
>  #endif
>  
>  #ifndef pmd_addr_end
> -#define pmd_addr_end(pmd, addr, end) \
> -({   unsigned long __boundary = ((addr) + PMD_SIZE) & PMD_MASK;  \
> - (__boundary - 1 < (end) - 1)? __boundary: (end);\
> -})
> +#define pmd_addr_end pmd_addr_end
> +static inline unsigned long pmd_addr_end(pmd_t pmd, unsigned long addr, 
> unsigned long end)
> +{unsigned long __boundary = (addr + PMD_SIZE) & PMD_MASK;
> + return (__boundary - 1 < end - 1) ? __boundary : end;
> +}
>  #endif
>  
>  /*
> -- 
> 2.17.1
> 

-- 
Sincerely yours,
Mike.

[RFC PATCH v2 3/3] mm: make generic pXd_addr_end() macros inline functions

2020-09-07 Thread Gerald Schaefer 
From: Alexander Gordeev 

Since pXd_addr_end() macros take pXd page-table entry as a
parameter it makes sense to check the entry type on compile.
Even though most archs do not make use of page-table entries
in pXd_addr_end() calls, checking the type in traversal code
paths could help to avoid subtle bugs.

Signed-off-by: Alexander Gordeev 
Signed-off-by: Gerald Schaefer 
---
 include/linux/pgtable.h | 36 
 1 file changed, 20 insertions(+), 16 deletions(-)

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 67ebc22cf83d..d9e7d16c2263 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -656,31 +656,35 @@ static inline int arch_unmap_one(struct mm_struct *mm,
  */
 
 #ifndef pgd_addr_end
-#define pgd_addr_end(pgd, addr, end)   \
-({ unsigned long __boundary = ((addr) + PGDIR_SIZE) & PGDIR_MASK;  \
-   (__boundary - 1 < (end) - 1)? __boundary: (end);\
-})
+#define pgd_addr_end pgd_addr_end
+static inline unsigned long pgd_addr_end(pgd_t pgd, unsigned long addr, 
unsigned long end)
+{  unsigned long __boundary = (addr + PGDIR_SIZE) & PGDIR_MASK;
+   return (__boundary - 1 < end - 1) ? __boundary : end;
+}
 #endif
 
 #ifndef p4d_addr_end
-#define p4d_addr_end(p4d, addr, end)   \
-({ unsigned long __boundary = ((addr) + P4D_SIZE) & P4D_MASK;  \
-   (__boundary - 1 < (end) - 1)? __boundary: (end);\
-})
+#define p4d_addr_end p4d_addr_end
+static inline unsigned long p4d_addr_end(p4d_t p4d, unsigned long addr, 
unsigned long end)
+{  unsigned long __boundary = (addr + P4D_SIZE) & P4D_MASK;
+   return (__boundary - 1 < end - 1) ? __boundary : end;
+}
 #endif
 
 #ifndef pud_addr_end
-#define pud_addr_end(pud, addr, end)   \
-({ unsigned long __boundary = ((addr) + PUD_SIZE) & PUD_MASK;  \
-   (__boundary - 1 < (end) - 1)? __boundary: (end);\
-})
+#define pud_addr_end pud_addr_end
+static inline unsigned long pud_addr_end(pud_t pud, unsigned long addr, 
unsigned long end)
+{  unsigned long __boundary = (addr + PUD_SIZE) & PUD_MASK;
+   return (__boundary - 1 < end - 1) ? __boundary : end;
+}
 #endif
 
 #ifndef pmd_addr_end
-#define pmd_addr_end(pmd, addr, end)   \
-({ unsigned long __boundary = ((addr) + PMD_SIZE) & PMD_MASK;  \
-   (__boundary - 1 < (end) - 1)? __boundary: (end);\
-})
+#define pmd_addr_end pmd_addr_end
+static inline unsigned long pmd_addr_end(pmd_t pmd, unsigned long addr, 
unsigned long end)
+{  unsigned long __boundary = (addr + PMD_SIZE) & PMD_MASK;
+   return (__boundary - 1 < end - 1) ? __boundary : end;
+}
 #endif
 
 /*
-- 
2.17.1