Merge "ANDROID: mm: use raw seqcount variants in vm_write_*" (8cdb56c0) · Commits · e / devices / android_kernel_oneplus_sm7250

include/linux/mm.h

+5 −24

Original line number	Diff line number	Diff line
		@@ -1498,22 +1498,13 @@ int generic_access_phys(struct vm_area_struct *vma, unsigned long addr,
		#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)
		{
		/*
		* The reads never spins and preemption
		* disablement is not required.
		*/
		raw_write_seqcount_begin(&vma->vm_sequence);
		}
		static inline void vm_raw_write_end(struct vm_area_struct *vma)
		static inline void vm_write_end(struct vm_area_struct *vma)
		{
		raw_write_seqcount_end(&vma->vm_sequence);
		}
		@@ -1521,19 +1512,9 @@ static inline void vm_raw_write_end(struct vm_area_struct *vma)
		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);

mm/mmap.c

+9 −29

Original line number	Diff line number	Diff line
		@@ -735,29 +735,9 @@ 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);
		vm_write_begin(vma);
		if (next)
		vm_raw_write_begin(next);
		vm_write_begin(next);

		if (next && !insert) {
		struct vm_area_struct exporter = NULL, importer = NULL;
		@@ -841,8 +821,8 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
		error = anon_vma_clone(importer, exporter);
		if (error) {
		if (next && next != vma)
		vm_raw_write_end(next);
		vm_raw_write_end(vma);
		vm_write_end(next);
		vm_write_end(vma);
		return error;
		}
		}
		@@ -971,7 +951,7 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
		if (next->anon_vma)
		anon_vma_merge(vma, next);
		mm->map_count--;
		vm_raw_write_end(next);
		vm_write_end(next);
		put_vma(next);
		/*
		* In mprotect's case 6 (see comments on vma_merge),
		@@ -987,7 +967,7 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
		*/
		next = vma->vm_next;
		if (next)
		vm_raw_write_begin(next);
		vm_write_begin(next);
		} else {
		/*
		* For the scope of the comment "next" and
		@@ -1035,9 +1015,9 @@ int __vma_adjust(struct vm_area_struct *vma, unsigned long start,
		uprobe_mmap(insert);

		if (next && next != vma)
		vm_raw_write_end(next);
		vm_write_end(next);
		if (!keep_locked)
		vm_raw_write_end(vma);
		vm_write_end(vma);

		validate_mm(mm);

		@@ -3348,7 +3328,7 @@ struct vm_area_struct copy_vma(struct vm_area_struct *vmap,
		* that we protect it right now, and let the caller unprotect
		* it once the move is done.
		*/
		vm_raw_write_begin(new_vma);
		vm_write_begin(new_vma);
		vma_link(mm, new_vma, prev, rb_link, rb_parent);
		*need_rmap_locks = false;
		}

mm/mremap.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -300,7 +300,7 @@ static unsigned long move_vma(struct vm_area_struct *vma,
		* to be mapped in our back while we are copying the PTEs.
		*/
		if (vma != new_vma)
		vm_raw_write_begin(vma);
		vm_write_begin(vma);

		moved_len = move_page_tables(vma, old_addr, new_vma, new_addr, old_len,
		need_rmap_locks);
		@@ -319,7 +319,7 @@ static unsigned long move_vma(struct vm_area_struct *vma,
		move_page_tables(new_vma, new_addr, vma, old_addr, moved_len,
		true);
		if (vma != new_vma)
		vm_raw_write_end(vma);
		vm_write_end(vma);
		vma = new_vma;
		old_len = new_len;
		old_addr = new_addr;
		@@ -329,9 +329,9 @@ static unsigned long move_vma(struct vm_area_struct *vma,
		arch_remap(mm, old_addr, old_addr + old_len,
		new_addr, new_addr + new_len);
		if (vma != new_vma)
		vm_raw_write_end(vma);
		vm_write_end(vma);
		}
		vm_raw_write_end(new_vma);
		vm_write_end(new_vma);

		/* Conceal VM_ACCOUNT so old reservation is not undone */
		if (vm_flags & VM_ACCOUNT) {