[PATCH 10/22] sparc: mm: use mm_is_kernel() for kernel mm checks

[Kevin Brodsky <kevin.brodsky@arm.com>]

The new MMF_KERNEL flag identifies kernel-owned mm's. Checking the
flag with mm_is_kernel() is preferred over comparing directly
against &init_mm.

No functional change, as only init_mm has MMF_KERNEL set for now.

pgtable_64.h previously forward-declared init_mm to avoid pulling
in mm_types.h. It seems that including mm_types.h is not causing
troubles any more, so we can also use mm_is_kernel() there and drop
the forward declaration.

Assisted-by: Codex:GPT-5.5
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
---
 arch/sparc/include/asm/mmu_context_64.h | 2 +-
 arch/sparc/include/asm/pgtable_64.h     | 6 ++----
 arch/sparc/mm/init_64.c                 | 2 +-
 arch/sparc/mm/tlb.c                     | 2 +-
 4 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/arch/sparc/include/asm/mmu_context_64.h b/arch/sparc/include/asm/mmu_context_64.h
index 78bbacc14d2d..e88bc61aeb04 100644
--- a/arch/sparc/include/asm/mmu_context_64.h
+++ b/arch/sparc/include/asm/mmu_context_64.h
@@ -83,7 +83,7 @@ static inline void switch_mm(struct mm_struct *old_mm, struct mm_struct *mm, str
 	int cpu = smp_processor_id();
 
 	per_cpu(per_cpu_secondary_mm, cpu) = mm;
-	if (unlikely(mm == &init_mm))
+	if (unlikely(mm_is_kernel(mm)))
 		return;
 
 	spin_lock_irqsave(&mm->context.lock, flags);
diff --git a/arch/sparc/include/asm/pgtable_64.h b/arch/sparc/include/asm/pgtable_64.h
index 0837ebbc5dce..960f8bf1ec5a 100644
--- a/arch/sparc/include/asm/pgtable_64.h
+++ b/arch/sparc/include/asm/pgtable_64.h
@@ -86,6 +86,7 @@ extern unsigned long VMALLOC_END;
 #define vmemmap			((struct page *)VMEMMAP_BASE)
 
 #include <linux/sched.h>
+#include <linux/mm_types.h>
 #include <asm/tlbflush.h>
 
 bool kern_addr_valid(unsigned long addr);
@@ -885,9 +886,6 @@ static inline unsigned long pud_pfn(pud_t pud)
 #define p4d_set(p4dp, pudp)	\
 	(p4d_val(*(p4dp)) = (__pa((unsigned long) (pudp))))
 
-/* We cannot include <linux/mm_types.h> at this point yet: */
-extern struct mm_struct init_mm;
-
 /* Actual page table PTE updates.  */
 void tlb_batch_add(struct mm_struct *mm, unsigned long vaddr,
 		   pte_t *ptep, pte_t orig, int fullmm,
@@ -903,7 +901,7 @@ static void maybe_tlb_batch_add(struct mm_struct *mm, unsigned long vaddr,
 	 * SUN4V NOTE: _PAGE_VALID is the same value in both the SUN4U
 	 *             and SUN4V pte layout, so this inline test is fine.
 	 */
-	if (likely(mm != &init_mm) && pte_accessible(mm, orig))
+	if (likely(!mm_is_kernel(mm)) && pte_accessible(mm, orig))
 		tlb_batch_add(mm, vaddr, ptep, orig, fullmm, hugepage_shift);
 }
 
diff --git a/arch/sparc/mm/init_64.c b/arch/sparc/mm/init_64.c
index 103db4683b16..e0b678349e3a 100644
--- a/arch/sparc/mm/init_64.c
+++ b/arch/sparc/mm/init_64.c
@@ -788,7 +788,7 @@ static void mmu_context_wrap(void)
 		 */
 		mm = per_cpu(per_cpu_secondary_mm, cpu);
 
-		if (unlikely(!mm || mm == &init_mm))
+		if (unlikely(!mm || mm_is_kernel(mm)))
 			continue;
 
 		old_ctx = mm->context.sparc64_ctx_val;
diff --git a/arch/sparc/mm/tlb.c b/arch/sparc/mm/tlb.c
index 6d9dd5eb1328..47083c287a94 100644
--- a/arch/sparc/mm/tlb.c
+++ b/arch/sparc/mm/tlb.c
@@ -179,7 +179,7 @@ static void tlb_batch_pmd_scan(struct mm_struct *mm, unsigned long vaddr,
 static void __set_pmd_acct(struct mm_struct *mm, unsigned long addr,
 			   pmd_t orig, pmd_t pmd)
 {
-	if (mm == &init_mm)
+	if (mm_is_kernel(mm))
 		return;
 
 	if ((pmd_val(pmd) ^ pmd_val(orig)) & _PAGE_PMD_HUGE) {

-- 
2.51.2