Commit fb8090b6 authored by Liam R. Howlett's avatar Liam R. Howlett Committed by Linus Torvalds
Browse files

mm/mmap: add inline munmap_vma_range() for code readability 



There are two locations that have a block of code for munmapping a vma
range.  Change those two locations to use a function and add meaningful
comments about what happens to the arguments, which was unclear in the
previous code.

Signed-off-by: default avatarLiam R. Howlett <Liam.Howlett@Oracle.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Link: http://lkml.kernel.org/r/20200818154707.2515169-2-Liam.Howlett@Oracle.com


Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3903b55a

mm/mmap.c

+33 −15
Original line number Diff line number Diff line
@@ -575,6 +575,33 @@ static inline struct vm_area_struct *vma_next(struct mm_struct *mm, 


	return vma->vm_next;

}



/*

 * munmap_vma_range() - munmap VMAs that overlap a range.

 * @mm: The mm struct

 * @start: The start of the range.

 * @len: The length of the range.

 * @pprev: pointer to the pointer that will be set to previous vm_area_struct

 * @rb_link: the rb_node

 * @rb_parent: the parent rb_node

 *

 * Find all the vm_area_struct that overlap from @start to

 * @end and munmap them.  Set @pprev to the previous vm_area_struct.

 *

 * Returns: -ENOMEM on munmap failure or 0 on success.

 */

static inline int

munmap_vma_range(struct mm_struct *mm, unsigned long start, unsigned long len,

		 struct vm_area_struct **pprev, struct rb_node ***link,

		 struct rb_node **parent, struct list_head *uf)

{



	while (find_vma_links(mm, start, start + len, pprev, link, parent))

		if (do_munmap(mm, start, len, uf))

			return -ENOMEM;



	return 0;

}

static unsigned long count_vma_pages_range(struct mm_struct *mm,

		unsigned long addr, unsigned long end)

{
@@ -1721,13 +1748,9 @@ unsigned long mmap_region(struct file *file, unsigned long addr, 
			return -ENOMEM;

	}



	/* Clear old maps */

	while (find_vma_links(mm, addr, addr + len, &prev, &rb_link,

			      &rb_parent)) {

		if (do_munmap(mm, addr, len, uf))

	/* Clear old maps, set up prev, rb_link, rb_parent, and uf */

	if (munmap_vma_range(mm, addr, len, &prev, &rb_link, &rb_parent, uf))

		return -ENOMEM;

	}



	/*

	 * Private writable mapping: check memory availability

	 */
@@ -3063,14 +3086,9 @@ static int do_brk_flags(unsigned long addr, unsigned long len, unsigned long fla 
	if (error)

		return error;



	/*

	 * Clear old maps.  this also does some error checking for us

	 */

	while (find_vma_links(mm, addr, addr + len, &prev, &rb_link,

			      &rb_parent)) {

		if (do_munmap(mm, addr, len, uf))

	/* Clear old maps, set up prev, rb_link, rb_parent, and uf */

	if (munmap_vma_range(mm, addr, len, &prev, &rb_link, &rb_parent, uf))

		return -ENOMEM;

	}



	/* Check against address space limits *after* clearing old maps... */

	if (!may_expand_vm(mm, flags, len >> PAGE_SHIFT))

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