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

[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