mm: remove arch_flush_tlb_batched_pending() arch helper

Since commit 4b634918384c ("arm64/mm: Close theoretical race where stale
TLB entry remains valid"), all arches that use tlbbatch for reclaim
(arm64, riscv, x86) implement arch_flush_tlb_batched_pending() with a
flush_tlb_mm().

So let's simplify by removing the unnecessary abstraction and doing the
flush_tlb_mm() directly in flush_tlb_batched_pending().  This effectively
reverts commit db6c1f6f236d ("mm/tlbbatch: introduce
arch_flush_tlb_batched_pending()").

Link: https://lkml.kernel.org/r/20250609103132.447370-1-ryan.roberts@arm.com
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Suggested-by: Will Deacon <will@kernel.org>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Will Deacon <will@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

5 files changed, 1 insertions, 23 deletions

diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h
index aa9efee17277..18a5dc0c9a54 100644
--- a/arch/arm64/include/asm/tlbflush.h
+++ b/arch/arm64/include/asm/tlbflush.h
@@ -323,17 +323,6 @@ static inline bool arch_tlbbatch_should_defer(struct mm_struct *mm)
 }
 
 /*
- * If mprotect/munmap/etc occurs during TLB batched flushing, we need to ensure
- * all the previously issued TLBIs targeting mm have completed. But since we
- * can be executing on a remote CPU, a DSB cannot guarantee this like it can
- * for arch_tlbbatch_flush(). Our only option is to flush the entire mm.
- */
-static inline void arch_flush_tlb_batched_pending(struct mm_struct *mm)
-{
-	flush_tlb_mm(mm);
-}
-
-/*
  * To support TLB batched flush for multiple pages unmapping, we only send
  * the TLBI for each page in arch_tlbbatch_add_pending() and wait for the
  * completion at the end in arch_tlbbatch_flush(). Since we've already issued
diff --git a/arch/riscv/include/asm/tlbflush.h b/arch/riscv/include/asm/tlbflush.h
index 1a20dd746a49..eed0abc40514 100644
--- a/arch/riscv/include/asm/tlbflush.h
+++ b/arch/riscv/include/asm/tlbflush.h
@@ -63,7 +63,6 @@ void flush_pud_tlb_range(struct vm_area_struct *vma, unsigned long start,
 bool arch_tlbbatch_should_defer(struct mm_struct *mm);
 void arch_tlbbatch_add_pending(struct arch_tlbflush_unmap_batch *batch,
 		struct mm_struct *mm, unsigned long start, unsigned long end);
-void arch_flush_tlb_batched_pending(struct mm_struct *mm);
 void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch);
 
 extern unsigned long tlb_flush_all_threshold;
diff --git a/arch/riscv/mm/tlbflush.c b/arch/riscv/mm/tlbflush.c
index e737ba7949b1..8404530ec00f 100644
--- a/arch/riscv/mm/tlbflush.c
+++ b/arch/riscv/mm/tlbflush.c
@@ -234,11 +234,6 @@ void arch_tlbbatch_add_pending(struct arch_tlbflush_unmap_batch *batch,
 	mmu_notifier_arch_invalidate_secondary_tlbs(mm, start, end);
 }
 
-void arch_flush_tlb_batched_pending(struct mm_struct *mm)
-{
-	flush_tlb_mm(mm);
-}
-
 void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch)
 {
 	__flush_tlb_range(NULL, &batch->cpumask,
diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
index e9b81876ebe4..00daedfefc1b 100644
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -356,11 +356,6 @@ static inline void arch_tlbbatch_add_pending(struct arch_tlbflush_unmap_batch *b
 	mmu_notifier_arch_invalidate_secondary_tlbs(mm, 0, -1UL);
 }
 
-static inline void arch_flush_tlb_batched_pending(struct mm_struct *mm)
-{
-	flush_tlb_mm(mm);
-}
-
 extern void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch);
 
 static inline bool pte_flags_need_flush(unsigned long oldflags,
diff --git a/mm/rmap.c b/mm/rmap.c
index 4c833b43fef9..f93ce27132ab 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -746,7 +746,7 @@ void flush_tlb_batched_pending(struct mm_struct *mm)
 	int flushed = batch >> TLB_FLUSH_BATCH_FLUSHED_SHIFT;
 
 	if (pending != flushed) {
-		arch_flush_tlb_batched_pending(mm);
+		flush_tlb_mm(mm);
 		/*
 		 * If the new TLB flushing is pending during flushing, leave
 		 * mm->tlb_flush_batched as is, to avoid losing flushing.