Re: [PATCH] arm64/mm: Use phys_to_page() to access pgtable memory

From: Gavin Shan
Date: Mon Apr 27 2020 - 19:45:45 EST


Hi Mark,

On 4/24/20 7:22 PM, Mark Rutland wrote:
On Fri, Apr 24, 2020 at 02:48:54PM +1000, Gavin Shan wrote:
The macros {pgd, pud, pmd}_page() retrieves the page struct of the
corresponding page frame, which is reserved as page table. There
is already a macro (phys_to_page), defined in memory.h, to convert
the physical address to the page struct. So it's reasonable to
use that in pgtable.h.

Signed-off-by: Gavin Shan <gshan@xxxxxxxxxx>

It might be worth pointing out that phys_to_page() is defined as:

#define phys_to_page(phys) (pfn_to_page(__phys_to_pfn(phys)))

... so this is obviously equivalent.

Given that, and given we already explicitly include <asm/memory.h>, this
looks like a nice cleanup to me.

With or without the commit message addition:

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

Mark.


Thanks for the comments. I will post v2 shortly, which has the improved
commit log and your reviewed-by.

Thanks,
Gavin

---
arch/arm64/include/asm/pgtable.h | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 538c85e62f86..8c20e2bd6287 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -508,7 +508,7 @@ static inline void pte_unmap(pte_t *pte) { }
#define pte_set_fixmap_offset(pmd, addr) pte_set_fixmap(pte_offset_phys(pmd, addr))
#define pte_clear_fixmap() clear_fixmap(FIX_PTE)
-#define pmd_page(pmd) pfn_to_page(__phys_to_pfn(__pmd_to_phys(pmd)))
+#define pmd_page(pmd) phys_to_page(__pmd_to_phys(pmd))
/* use ONLY for statically allocated translation tables */
#define pte_offset_kimg(dir,addr) ((pte_t *)__phys_to_kimg(pte_offset_phys((dir), (addr))))
@@ -566,7 +566,7 @@ static inline phys_addr_t pud_page_paddr(pud_t pud)
#define pmd_set_fixmap_offset(pud, addr) pmd_set_fixmap(pmd_offset_phys(pud, addr))
#define pmd_clear_fixmap() clear_fixmap(FIX_PMD)
-#define pud_page(pud) pfn_to_page(__phys_to_pfn(__pud_to_phys(pud)))
+#define pud_page(pud) phys_to_page(__pud_to_phys(pud))
/* use ONLY for statically allocated translation tables */
#define pmd_offset_kimg(dir,addr) ((pmd_t *)__phys_to_kimg(pmd_offset_phys((dir), (addr))))
@@ -624,7 +624,7 @@ static inline phys_addr_t pgd_page_paddr(pgd_t pgd)
#define pud_set_fixmap_offset(pgd, addr) pud_set_fixmap(pud_offset_phys(pgd, addr))
#define pud_clear_fixmap() clear_fixmap(FIX_PUD)
-#define pgd_page(pgd) pfn_to_page(__phys_to_pfn(__pgd_to_phys(pgd)))
+#define pgd_page(pgd) phys_to_page(__pgd_to_phys(pgd))
/* use ONLY for statically allocated translation tables */
#define pud_offset_kimg(dir,addr) ((pud_t *)__phys_to_kimg(pud_offset_phys((dir), (addr))))
--
2.23.0