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mmap: use the VMA iterator in count_vma_pages_range()

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This simplifies the implementation and is faster than using the linked
list.

Link: https://lkml.kernel.org/r/20220906194824.2110408-11-Liam.Howlett@oracle.com
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Howells <dhowells@redhat.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Matthew Wilcox (Oracle) 2022-09-06 19:48:46 +00:00 committed by Andrew Morton
parent f39af05949
commit 2e3af1db17
1 changed files with 7 additions and 17 deletions
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24
mm/mmap.c
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@ -629,29 +629,19 @@ munmap_vma_range(struct mm_struct *mm, unsigned long start, unsigned long len,
return 0;
}
static unsigned long count_vma_pages_range(struct mm_struct *mm,
unsigned long addr, unsigned long end)
{
unsigned long nr_pages = 0;
VMA_ITERATOR(vmi, mm, addr);
struct vm_area_struct *vma;
unsigned long nr_pages = 0;
/* Find first overlapping mapping */
vma = find_vma_intersection(mm, addr, end);
if (!vma)
return 0;
for_each_vma_range(vmi, vma, end) {
unsigned long vm_start = max(addr, vma->vm_start);
unsigned long vm_end = min(end, vma->vm_end);
nr_pages = (min(end, vma->vm_end) -
max(addr, vma->vm_start)) >> PAGE_SHIFT;
/* Iterate over the rest of the overlaps */
for (vma = vma->vm_next; vma; vma = vma->vm_next) {
unsigned long overlap_len;
if (vma->vm_start > end)
break;
overlap_len = min(end, vma->vm_end) - vma->vm_start;
nr_pages += overlap_len >> PAGE_SHIFT;
nr_pages += PHYS_PFN(vm_end - vm_start);
}
return nr_pages;