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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: Liam R. Howlett <Liam.Howlett@Oracle.com>
Tested-by: Yu 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: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Liam R. Howlett 2022-09-06 19:48:50 +00:00 committed by Andrew Morton
parent 2e7ce7d354
commit abdba2dda0
3 changed files with 44 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
include/linux/mm.h
View File

@ -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

29
mm/mmap.c
View File

@ -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

11
mm/nommu.c
View File

@ -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