diff mbox series

arm64: mm: simplify the page end calculation in __create_pgd_mapping()

Message ID 20191103123559.8866-1-yamada.masahiro@socionext.com
State Accepted
Commit 32d1870877ba7675c642e903e5ef71c82a245325
Headers show
Series arm64: mm: simplify the page end calculation in __create_pgd_mapping() | expand

Commit Message

Masahiro Yamada Nov. 3, 2019, 12:35 p.m. UTC
Calculate the page-aligned end address more simply.

The local variable, "length" is unneeded.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

---

 arch/arm64/mm/mmu.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

-- 
2.17.1

Comments

Mark Rutland Nov. 5, 2019, 9:37 a.m. UTC | #1
On Sun, Nov 03, 2019 at 09:35:58PM +0900, Masahiro Yamada wrote:
> Calculate the page-aligned end address more simply.

> 

> The local variable, "length" is unneeded.

> 

> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

> ---

> 

>  arch/arm64/mm/mmu.c | 5 ++---

>  1 file changed, 2 insertions(+), 3 deletions(-)

> 

> diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c

> index 60c929f3683b..a9f541912289 100644

> --- a/arch/arm64/mm/mmu.c

> +++ b/arch/arm64/mm/mmu.c

> @@ -338,7 +338,7 @@ static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,

>  				 phys_addr_t (*pgtable_alloc)(int),

>  				 int flags)

>  {

> -	unsigned long addr, length, end, next;

> +	unsigned long addr, end, next;

>  	pgd_t *pgdp = pgd_offset_raw(pgdir, virt);

>  

>  	/*

> @@ -350,9 +350,8 @@ static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,

>  

>  	phys &= PAGE_MASK;

>  	addr = virt & PAGE_MASK;

> -	length = PAGE_ALIGN(size + (virt & ~PAGE_MASK));

> +	end = PAGE_ALIGN(virt + size);

>  

> -	end = addr + length;


While looking at this, I got confused by the old code and thought that
there was an existing bug, but I now see that's not the case, and the
old and new code are equivalent.

The new code looks cleaner, and leaves less room for confusion, so I
think that's preferable:

Reviewed-by: Mark Rutland <mark.rutland@arm.com>


Mark.

>  	do {

>  		next = pgd_addr_end(addr, end);

>  		alloc_init_pud(pgdp, addr, next, phys, prot, pgtable_alloc,

> -- 

> 2.17.1

>
Catalin Marinas Nov. 6, 2019, 11:17 a.m. UTC | #2
On Sun, Nov 03, 2019 at 09:35:58PM +0900, Masahiro Yamada wrote:
> Calculate the page-aligned end address more simply.

> 

> The local variable, "length" is unneeded.

> 

> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>


Queued for 5.5. Thanks.

-- 
Catalin
diff mbox series

Patch

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index 60c929f3683b..a9f541912289 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -338,7 +338,7 @@  static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
 				 phys_addr_t (*pgtable_alloc)(int),
 				 int flags)
 {
-	unsigned long addr, length, end, next;
+	unsigned long addr, end, next;
 	pgd_t *pgdp = pgd_offset_raw(pgdir, virt);
 
 	/*
@@ -350,9 +350,8 @@  static void __create_pgd_mapping(pgd_t *pgdir, phys_addr_t phys,
 
 	phys &= PAGE_MASK;
 	addr = virt & PAGE_MASK;
-	length = PAGE_ALIGN(size + (virt & ~PAGE_MASK));
+	end = PAGE_ALIGN(virt + size);
 
-	end = addr + length;
 	do {
 		next = pgd_addr_end(addr, end);
 		alloc_init_pud(pgdp, addr, next, phys, prot, pgtable_alloc,