Commit abdba2dd authored by Liam R. Howlett's avatar Liam R. Howlett Committed by Andrew Morton
Browse files

mm: use maple tree operations for find_vma_intersection() 

Move find_vma_intersection() to mmap.c and change implementation to maple
tree.

When searching for a vma within a range, it is easier to use the maple
tree interface.

Exported find_vma_intersection() for kvm module.

Link: https://lkml.kernel.org/r/20220906194824.2110408-24-Liam.Howlett@oracle.com


Signed-off-by: default avatarLiam R. Howlett <Liam.Howlett@Oracle.com>
Tested-by: default avatarYu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 2e7ce7d3

include/linux/mm.h

+4 −18
Original line number Diff line number Diff line
@@ -2778,26 +2778,12 @@ extern struct vm_area_struct * find_vma(struct mm_struct * mm, unsigned long add 
extern struct vm_area_struct * find_vma_prev(struct mm_struct * mm, unsigned long addr,

					     struct vm_area_struct **pprev);



/**

 * find_vma_intersection() - Look up the first VMA which intersects the interval

 * @mm: The process address space.

 * @start_addr: The inclusive start user address.

 * @end_addr: The exclusive end user address.

 *

 * Returns: The first VMA within the provided range, %NULL otherwise.  Assumes

 * start_addr < end_addr.

/*

 * Look up the first VMA which intersects the interval [start_addr, end_addr)

 * NULL if none.  Assume start_addr < end_addr.

 */

static inline

struct vm_area_struct *find_vma_intersection(struct mm_struct *mm,

					     unsigned long start_addr,

					     unsigned long end_addr)

{

	struct vm_area_struct *vma = find_vma(mm, start_addr);



	if (vma && end_addr <= vma->vm_start)

		vma = NULL;

	return vma;

}

			unsigned long start_addr, unsigned long end_addr);



/**

 * vma_lookup() - Find a VMA at a specific address

mm/mmap.c

+29 −0
Original line number Diff line number Diff line
@@ -2061,6 +2061,35 @@ get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, 


EXPORT_SYMBOL(get_unmapped_area);



/**

 * find_vma_intersection() - Look up the first VMA which intersects the interval

 * @mm: The process address space.

 * @start_addr: The inclusive start user address.

 * @end_addr: The exclusive end user address.

 *

 * Returns: The first VMA within the provided range, %NULL otherwise.  Assumes

 * start_addr < end_addr.

 */

struct vm_area_struct *find_vma_intersection(struct mm_struct *mm,

					     unsigned long start_addr,

					     unsigned long end_addr)

{

	struct vm_area_struct *vma;

	unsigned long index = start_addr;



	mmap_assert_locked(mm);

	/* Check the cache first. */

	vma = vmacache_find(mm, start_addr);

	if (likely(vma))

		return vma;



	vma = mt_find(&mm->mm_mt, &index, end_addr - 1);

	if (vma)

		vmacache_update(start_addr, vma);

	return vma;

}

EXPORT_SYMBOL(find_vma_intersection);



/**

 * find_vma() - Find the VMA for a given address, or the next VMA.

 * @mm: The mm_struct to check

mm/nommu.c

+11 −0
Original line number Diff line number Diff line
@@ -642,6 +642,17 @@ static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma) 
	vm_area_free(vma);

}



struct vm_area_struct *find_vma_intersection(struct mm_struct *mm,

					     unsigned long start_addr,

					     unsigned long end_addr)

{

	unsigned long index = start_addr;



	mmap_assert_locked(mm);

	return mt_find(&mm->mm_mt, &index, end_addr - 1);

}

EXPORT_SYMBOL(find_vma_intersection);



/*

 * look up the first VMA in which addr resides, NULL if none

 * - should be called with mm->mmap_lock at least held readlocked