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Code Issues Releases Wiki Activity

mm/mlock: use vma iterator and maple state instead of vma linked list 

Handle overflow checking in count_mm_mlocked_page_nr() differently.

Link: https://lkml.kernel.org/r/20220906194824.2110408-58-Liam.Howlett@oracle.com
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
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: 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:
Matthew Wilcox (Oracle) 2022-09-06 19:49:02 +00:00 committed by Andrew Morton
parent 66850be55e
commit 33108b05f3
1 changed files with 19 additions and 16 deletions
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35
mm/mlock.c
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@ -471,6 +471,7 @@ static int apply_vma_lock_flags(unsigned long start, size_t len,
unsigned long nstart, end, tmp;
struct vm_area_struct *vma, *prev;
int error;
MA_STATE(mas, &current->mm->mm_mt, start, start);
VM_BUG_ON(offset_in_page(start));
VM_BUG_ON(len != PAGE_ALIGN(len));
@ -479,13 +480,14 @@ static int apply_vma_lock_flags(unsigned long start, size_t len,
return -EINVAL;
if (end == start)
return 0;
vma = find_vma(current->mm, start);
if (!vma || vma->vm_start > start)
vma = mas_walk(&mas);
if (!vma)
return -ENOMEM;
prev = vma->vm_prev;
if (start > vma->vm_start)
prev = vma;
else
prev = mas_prev(&mas, 0);
for (nstart = start ; ; ) {
vm_flags_t newflags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
@ -505,7 +507,7 @@ static int apply_vma_lock_flags(unsigned long start, size_t len,
if (nstart >= end)
break;
vma = prev->vm_next;
vma = find_vma(prev->vm_mm, prev->vm_end);
if (!vma || vma->vm_start != nstart) {
error = -ENOMEM;
break;
@ -526,24 +528,23 @@ static unsigned long count_mm_mlocked_page_nr(struct mm_struct *mm,
{
struct vm_area_struct *vma;
unsigned long count = 0;
unsigned long end;
VMA_ITERATOR(vmi, mm, start);
if (mm == NULL)
mm = current->mm;
vma = find_vma(mm, start);
if (vma == NULL)
return 0;
for (; vma ; vma = vma->vm_next) {
if (start >= vma->vm_end)
continue;
if (start + len <= vma->vm_start)
break;
/* Don't overflow past ULONG_MAX */
if (unlikely(ULONG_MAX - len < start))
end = ULONG_MAX;
else
end = start + len;
for_each_vma_range(vmi, vma, end) {
if (vma->vm_flags & VM_LOCKED) {
if (start > vma->vm_start)
count -= (start - vma->vm_start);
if (start + len < vma->vm_end) {
count += start + len - vma->vm_start;
if (end < vma->vm_end) {
count += end - vma->vm_start;
break;
}
count += vma->vm_end - vma->vm_start;
@ -659,6 +660,7 @@ SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len)
*/
static int apply_mlockall_flags(int flags)
{
MA_STATE(mas, &current->mm->mm_mt, 0, 0);
struct vm_area_struct *vma, *prev = NULL;
vm_flags_t to_add = 0;
@ -679,7 +681,7 @@ static int apply_mlockall_flags(int flags)
to_add |= VM_LOCKONFAULT;
}
for (vma = current->mm->mmap; vma ; vma = prev->vm_next) {
mas_for_each(&mas, vma, ULONG_MAX) {
vm_flags_t newflags;
newflags = vma->vm_flags & VM_LOCKED_CLEAR_MASK;
@ -687,6 +689,7 @@ static int apply_mlockall_flags(int flags)
/* Ignore errors */
mlock_fixup(vma, &prev, vma->vm_start, vma->vm_end, newflags);
mas_pause(&mas);
cond_resched();
}
out: