From 9b5757bdc7635ee22d7442f156f15d67210386d7 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <peterz@infradead.org>
Date: Mon, 16 Nov 2020 14:17:38 +0800
Subject: [PATCH] asm-generic/tlb: Remove tlb_flush_mmu_free()

mainline inclusion
from mainline-v5.2-rc1
commit fa0aafb8acb684e68231ff0a547ed249f8dc31a5
category:feature
bugzilla:NA
CVE:NA

-------------------

As the comment notes; it is a potentially dangerous operation. Just
use tlb_flush_mmu(), that will skip the (double) TLB invalidate if
it really isn't needed anyway.

No change in behavior intended.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
 include/asm-generic/tlb.h | 10 +++-------
 mm/memory.c               |  2 +-
 mm/mmu_gather.c           |  2 +-
 3 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/include/asm-generic/tlb.h b/include/asm-generic/tlb.h
index ef1c077dd07e..6998e6d7c728 100644
--- a/include/asm-generic/tlb.h
+++ b/include/asm-generic/tlb.h
@@ -66,16 +66,13 @@
  *    call before __tlb_remove_page*() to set the current page-size; implies a
  *    possible tlb_flush_mmu() call.
  *
- *  - tlb_flush_mmu() / tlb_flush_mmu_tlbonly() / tlb_flush_mmu_free()
+ *  - tlb_flush_mmu() / tlb_flush_mmu_tlbonly()
  *
  *    tlb_flush_mmu_tlbonly() - does the TLB invalidate (and resets
  *                              related state, like the range)
  *
- *    tlb_flush_mmu_free() - frees the queued pages; make absolutely
- *			     sure no additional tlb_remove_page()
- *			     calls happen between _tlbonly() and this.
- *
- *    tlb_flush_mmu() - the above two calls.
+ *    tlb_flush_mmu() - in addition to the above TLB invalidate, also frees
+ *			whatever pages are still batched.
  *
  *  - mmu_gather::fullmm
  *
@@ -266,7 +263,6 @@ void arch_tlb_gather_mmu(struct mmu_gather *tlb,
 void tlb_flush_mmu(struct mmu_gather *tlb);
 void arch_tlb_finish_mmu(struct mmu_gather *tlb,
 			 unsigned long start, unsigned long end, bool force);
-void tlb_flush_mmu_free(struct mmu_gather *tlb);
 
 static inline void __tlb_adjust_range(struct mmu_gather *tlb,
 				      unsigned long address,
diff --git a/mm/memory.c b/mm/memory.c
index 85dd6fb68be1..7503203c8436 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1168,7 +1168,7 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
 	 */
 	if (force_flush) {
 		force_flush = 0;
-		tlb_flush_mmu_free(tlb);
+		tlb_flush_mmu(tlb);
 		if (addr != end)
 			goto again;
 	}
diff --git a/mm/mmu_gather.c b/mm/mmu_gather.c
index cac2eb492ee9..b5d53f170a00 100644
--- a/mm/mmu_gather.c
+++ b/mm/mmu_gather.c
@@ -91,7 +91,7 @@ bool __tlb_remove_page_size(struct mmu_gather *tlb, struct page *page, int page_
 
 #endif /* HAVE_MMU_GATHER_NO_GATHER */
 
-void tlb_flush_mmu_free(struct mmu_gather *tlb)
+static void tlb_flush_mmu_free(struct mmu_gather *tlb)
 {
 #ifdef CONFIG_HAVE_RCU_TABLE_FREE
 	tlb_table_flush(tlb);
-- 
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