[PATCH v2] mm: clean up redundant code

[Feng Lee <379943137@qq.com>]

Remove pgd_offset_gate() completely and simply make the single
caller use pgd_offset()

It appears that the gate area resides in the kernel-mapped segment
exclusively on IA64. Therefore, removing pgd_offset_k is safe since
IA64 is now obsolete.

Signed-off-by: Feng Lee <379943137@qq.com>

---
Changes in v2:
  - remove pgd_offset_gate completely
  - remove pgd_offset_k from the get_gate_page function completely
---
 include/linux/pgtable.h | 4 ----
 mm/gup.c                | 5 +----
 2 files changed, 1 insertion(+), 8 deletions(-)

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index b50447ef1c92..f1e890b60460 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -1164,10 +1164,6 @@ static inline void arch_swap_restore(swp_entry_t entry, struct folio *folio)
 }
 #endif
 
-#ifndef __HAVE_ARCH_PGD_OFFSET_GATE
-#define pgd_offset_gate(mm, addr)	pgd_offset(mm, addr)
-#endif
-
 #ifndef __HAVE_ARCH_MOVE_PTE
 #define move_pte(pte, old_addr, new_addr)	(pte)
 #endif
diff --git a/mm/gup.c b/mm/gup.c
index f32168339390..0685403fe510 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -1101,10 +1101,7 @@ static int get_gate_page(struct mm_struct *mm, unsigned long address,
 	/* user gate pages are read-only */
 	if (gup_flags & FOLL_WRITE)
 		return -EFAULT;
-	if (address > TASK_SIZE)
-		pgd = pgd_offset_k(address);
-	else
-		pgd = pgd_offset_gate(mm, address);
+	pgd = pgd_offset(mm, address);
 	if (pgd_none(*pgd))
 		return -EFAULT;
 	p4d = p4d_offset(pgd, address);
-- 
2.49.0