mmu_gather: Let there be one tlb_{start,end}_vma() implementation

Now that architectures are no longer allowed to override
tlb_{start,end}_vma() re-arrange code so that there is only one
implementation for each of these functions.

This much simplifies trying to figure out what they actually do.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/asm-generic/tlb.h

@@ -349,8 +349,8 @@ static inline void __tlb_reset_range(struct mmu_gather *tlb)
 
 #ifdef CONFIG_MMU_GATHER_NO_RANGE
 
-#if defined(tlb_flush) || defined(tlb_start_vma) || defined(tlb_end_vma)
-#error MMU_GATHER_NO_RANGE relies on default tlb_flush(), tlb_start_vma() and tlb_end_vma()
+#if defined(tlb_flush)
+#error MMU_GATHER_NO_RANGE relies on default tlb_flush()
 #endif
 
 /*
@@ -370,17 +370,10 @@ static inline void tlb_flush(struct mmu_gather *tlb)
 static inline void
 tlb_update_vma_flags(struct mmu_gather *tlb, struct vm_area_struct *vma) { }
 
-#define tlb_end_vma tlb_end_vma
-static inline void tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vma) { }
-
 #else /* CONFIG_MMU_GATHER_NO_RANGE */
 
 #ifndef tlb_flush
 
-#if defined(tlb_start_vma) || defined(tlb_end_vma)
-#error Default tlb_flush() relies on default tlb_start_vma() and tlb_end_vma()
-#endif
-
 /*
  * When an architecture does not provide its own tlb_flush() implementation
  * but does have a reasonably efficient flush_vma_range() implementation
@@ -501,7 +494,6 @@ static inline unsigned long tlb_get_unmap_size(struct mmu_gather *tlb)
  * case where we're doing a full MM flush.  When we're doing a munmap,
  * the vmas are adjusted to only cover the region to be torn down.
  */
-#ifndef tlb_start_vma
 static inline void tlb_start_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
 {
 	if (tlb->fullmm)
@@ -512,9 +504,7 @@ static inline void tlb_start_vma(struct mmu_gather *tlb, struct vm_area_struct *
 	flush_cache_range(vma, vma->vm_start, vma->vm_end);
 #endif
 }
-#endif
 
-#ifndef tlb_end_vma
 static inline void tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
 {
 	if (tlb->fullmm || IS_ENABLED(CONFIG_MMU_GATHER_MERGE_VMAS))
@@ -528,7 +518,6 @@ static inline void tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vm
 	 */
 	tlb_flush_mmu_tlbonly(tlb);
 }
-#endif
 
 /*
  * tlb_flush_{pte|pmd|pud|p4d}_range() adjust the tlb->start and tlb->end,