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Unverified Commit f005ca24 authored by Minchan Kim's avatar Minchan Kim Committed by basamaryan
Browse files

Revert "mm: VMA sequence count" 



This reverts commit 184ccc18.

Bug: 128240262
Change-Id: I7293939d08e6b9603d82464f4538a573b3407a88
Signed-off-by: default avatarMinchan Kim <minchan@google.com>
parent 1fe3771a

include/linux/mm.h

+0 −44
Original line number Diff line number Diff line
@@ -1373,9 +1373,6 @@ struct zap_details { 
static inline void INIT_VMA(struct vm_area_struct *vma)

{

	INIT_LIST_HEAD(&vma->anon_vma_chain);

#ifdef CONFIG_SPECULATIVE_PAGE_FAULT

	seqcount_init(&vma->vm_sequence);

#endif

}



struct page *_vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
@@ -1460,47 +1457,6 @@ static inline void unmap_shared_mapping_range(struct address_space *mapping, 
	unmap_mapping_range(mapping, holebegin, holelen, 0);

}



#ifdef CONFIG_SPECULATIVE_PAGE_FAULT

static inline void vm_write_begin(struct vm_area_struct *vma)

{

	write_seqcount_begin(&vma->vm_sequence);

}

static inline void vm_write_begin_nested(struct vm_area_struct *vma,

					 int subclass)

{

	write_seqcount_begin_nested(&vma->vm_sequence, subclass);

}

static inline void vm_write_end(struct vm_area_struct *vma)

{

	write_seqcount_end(&vma->vm_sequence);

}

static inline void vm_raw_write_begin(struct vm_area_struct *vma)

{

	raw_write_seqcount_begin(&vma->vm_sequence);

}

static inline void vm_raw_write_end(struct vm_area_struct *vma)

{

	raw_write_seqcount_end(&vma->vm_sequence);

}

#else

static inline void vm_write_begin(struct vm_area_struct *vma)

{

}

static inline void vm_write_begin_nested(struct vm_area_struct *vma,

					 int subclass)

{

}

static inline void vm_write_end(struct vm_area_struct *vma)

{

}

static inline void vm_raw_write_begin(struct vm_area_struct *vma)

{

}

static inline void vm_raw_write_end(struct vm_area_struct *vma)

{

}

#endif /* CONFIG_SPECULATIVE_PAGE_FAULT */



extern void truncate_pagecache(struct inode *inode, loff_t new);

extern void truncate_setsize(struct inode *inode, loff_t newsize);

void pagecache_isize_extended(struct inode *inode, loff_t from, loff_t to);

include/linux/mm_types.h

+0 −3
Original line number Diff line number Diff line
@@ -349,9 +349,6 @@ struct vm_area_struct { 
	struct mempolicy *vm_policy;	/* NUMA policy for the VMA */

#endif

	struct vm_userfaultfd_ctx vm_userfaultfd_ctx;

#ifdef CONFIG_SPECULATIVE_PAGE_FAULT

	seqcount_t vm_sequence;

#endif

} __randomize_layout;



struct core_thread {

mm/memory.c

+0 −2
Original line number Diff line number Diff line
@@ -1552,7 +1552,6 @@ void unmap_page_range(struct mmu_gather *tlb, 
	unsigned long next;



	BUG_ON(addr >= end);

	vm_write_begin(vma);

	tlb_start_vma(tlb, vma);

	pgd = pgd_offset(vma->vm_mm, addr);

	do {
@@ -1562,7 +1561,6 @@ void unmap_page_range(struct mmu_gather *tlb, 
		next = zap_p4d_range(tlb, vma, pgd, addr, next, details);

	} while (pgd++, addr = next, addr != end);

	tlb_end_vma(tlb, vma);

	vm_write_end(vma);

}

mm/mmap.c

+0 −31
Original line number Diff line number Diff line
@@ -687,30 +687,6 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start, 
	long adjust_next = 0;

	int remove_next = 0;



	/*

	 * Why using vm_raw_write*() functions here to avoid lockdep's warning ?

	 *

	 * Locked is complaining about a theoretical lock dependency, involving

	 * 3 locks:

	 *   mapping->i_mmap_rwsem --> vma->vm_sequence --> fs_reclaim

	 *

	 * Here are the major path leading to this dependency :

	 *  1. __vma_adjust() mmap_sem  -> vm_sequence -> i_mmap_rwsem

	 *  2. move_vmap() mmap_sem -> vm_sequence -> fs_reclaim

	 *  3. __alloc_pages_nodemask() fs_reclaim -> i_mmap_rwsem

	 *  4. unmap_mapping_range() i_mmap_rwsem -> vm_sequence

	 *

	 * So there is no way to solve this easily, especially because in

	 * unmap_mapping_range() the i_mmap_rwsem is grab while the impacted

	 * VMAs are not yet known.

	 * However, the way the vm_seq is used is guarantying that we will

	 * never block on it since we just check for its value and never wait

	 * for it to move, see vma_has_changed() and handle_speculative_fault().

	 */

	vm_raw_write_begin(vma);

	if (next)

		vm_raw_write_begin(next);



	if (next && !insert) {

		struct vm_area_struct *exporter = NULL, *importer = NULL;
@@ -921,7 +897,6 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start, 
			anon_vma_merge(vma, next);

		mm->map_count--;

		mpol_put(vma_policy(next));

		vm_raw_write_end(next);

		kmem_cache_free(vm_area_cachep, next);

		/*

		 * In mprotect's case 6 (see comments on vma_merge),
@@ -936,8 +911,6 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start, 
			 * "vma->vm_next" gap must be updated.

			 */

			next = vma->vm_next;

			if (next)

				vm_raw_write_begin(next);

		} else {

			/*

			 * For the scope of the comment "next" and
@@ -984,10 +957,6 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start, 
	if (insert && file)

		uprobe_mmap(insert);



	if (next && next != vma)

		vm_raw_write_end(next);

	vm_raw_write_end(vma);



	validate_mm(mm);



	return 0;