Re: [PATCH] arm64: mm: Drop duplicate check in pmd_trans_huge()

From: Dev Jain
Date: Thu May 08 2025 - 00:00:28 EST




On 08/05/25 9:21 am, Gavin Shan wrote:
pmd_val(pmd) is inclusive to pmd_present(pmd) since the PMD entry
value isn't zero when pmd_present() returns true. Just drop the
duplicate check done by pmd_val(pmd).

No functional changes intended.

Signed-off-by: Gavin Shan <gshan@xxxxxxxxxx>
---
Found this by code inspection
---
arch/arm64/include/asm/pgtable.h | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index d3b538be1500..2599b9b8666f 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -739,8 +739,7 @@ static inline int pmd_trans_huge(pmd_t pmd)
* If pmd is present-invalid, pmd_table() won't detect it
* as a table, so force the valid bit for the comparison.
*/
- return pmd_val(pmd) && pmd_present(pmd) &&
- !pmd_table(__pmd(pmd_val(pmd) | PTE_VALID));
+ return pmd_present(pmd) && !pmd_table(__pmd(pmd_val(pmd) | PTE_VALID));
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */

LGTM

Reviewed-by: Dev Jain <dev.jain@xxxxxxx>