[PATCH 17/18] asm-generic/tlb: Remove tlb_flush_mmu_free()
From: Peter Zijlstra
Date: Wed Sep 26 2018 - 07:55:19 EST
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.
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
include/asm-generic/tlb.h | 10 +++-------
mm/memory.c | 2 +-
mm/mmu_gather.c | 2 +-
3 files changed, 5 insertions(+), 9 deletions(-)
--- a/include/asm-generic/tlb.h
+++ b/include/asm-generic/tlb.h
@@ -67,16 +67,13 @@
* 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
*
@@ -274,7 +271,6 @@ void arch_tlb_gather_mmu(struct mmu_gath
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,
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1155,7 +1155,7 @@ static unsigned long zap_pte_range(struc
*/
if (force_flush) {
force_flush = 0;
- tlb_flush_mmu_free(tlb);
+ tlb_flush_mmu(tlb);
if (addr != end)
goto again;
}
--- a/mm/mmu_gather.c
+++ b/mm/mmu_gather.c
@@ -91,7 +91,7 @@ bool __tlb_remove_page_size(struct mmu_g
#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);