diff --git a/mm/mlock.c b/mm/mlock.c
index 45eb650b9654e..e13918d4fc4f8 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -139,49 +139,36 @@ static void munlock_vma_page(struct page *page)
}
/**
- * __mlock_vma_pages_range() - mlock/munlock a range of pages in the vma.
+ * __mlock_vma_pages_range() - mlock a range of pages in the vma.
* @vma: target vma
* @start: start address
* @end: end address
- * @mlock: 0 indicate munlock, otherwise mlock.
*
- * If @mlock == 0, unlock an mlocked range;
- * else mlock the range of pages. This takes care of making the pages present ,
- * too.
+ * This takes care of making the pages present too.
*
* return 0 on success, negative error code on error.
*
* vma->vm_mm->mmap_sem must be held for at least read.
*/
static long __mlock_vma_pages_range(struct vm_area_struct *vma,
- unsigned long start, unsigned long end,
- int mlock)
+ unsigned long start, unsigned long end)
{
struct mm_struct *mm = vma->vm_mm;
unsigned long addr = start;
struct page *pages[16]; /* 16 gives a reasonable batch */
int nr_pages = (end - start) / PAGE_SIZE;
int ret = 0;
- int gup_flags = 0;
+ int gup_flags;
VM_BUG_ON(start & ~PAGE_MASK);
VM_BUG_ON(end & ~PAGE_MASK);
VM_BUG_ON(start < vma->vm_start);
VM_BUG_ON(end > vma->vm_end);
- VM_BUG_ON((!rwsem_is_locked(&mm->mmap_sem)) &&
- (atomic_read(&mm->mm_users) != 0));
-
- /*
- * mlock: don't page populate if vma has PROT_NONE permission.
- * munlock: always do munlock although the vma has PROT_NONE
- * permission, or SIGKILL is pending.
- */
- if (!mlock)
- gup_flags |= GUP_FLAGS_IGNORE_VMA_PERMISSIONS |
- GUP_FLAGS_IGNORE_SIGKILL;
+ VM_BUG_ON(!rwsem_is_locked(&mm->mmap_sem));
+ gup_flags = 0;
if (vma->vm_flags & VM_WRITE)
- gup_flags |= GUP_FLAGS_WRITE;
+ gup_flags = GUP_FLAGS_WRITE;
while (nr_pages > 0) {
int i;
@@ -201,19 +188,10 @@ static long __mlock_vma_pages_range(struct vm_area_struct *vma,
* This can happen for, e.g., VM_NONLINEAR regions before
* a page has been allocated and mapped at a given offset,
* or for addresses that map beyond end of a file.
- * We'll mlock the the pages if/when they get faulted in.
+ * We'll mlock the pages if/when they get faulted in.
*/
if (ret < 0)
break;
- if (ret == 0) {
- /*
- * We know the vma is there, so the only time
- * we cannot get a single page should be an
- * error (ret < 0) case.
- */
- WARN_ON(1);
- break;
- }
lru_add_drain(); /* push cached pages to LRU */
@@ -224,28 +202,22 @@ static long __mlock_vma_pages_range(struct vm_area_struct *vma,
/*
* Because we lock page here and migration is blocked
* by the elevated reference, we need only check for
- * page truncation (file-cache only).
+ * file-cache page truncation. This page->mapping
+ * check also neatly skips over the ZERO_PAGE(),
+ * though if that's common we'd prefer not to lock it.
*/
- if (page->mapping) {
- if (mlock)
- mlock_vma_page(page);
- else
- munlock_vma_page(page);
- }
+ if (page->mapping)
+ mlock_vma_page(page);
unlock_page(page);
- put_page(page); /* ref from get_user_pages() */
-
- /*
- * here we assume that get_user_pages() has given us
- * a list of virtually contiguous pages.
- */
- addr += PAGE_SIZE; /* for next get_user_pages() */
- nr_pages--;
+ put_page(page); /* ref from get_user_pages() */
}
+
+ addr += ret * PAGE_SIZE;
+ nr_pages -= ret;
ret = 0;
}
- return ret; /* count entire vma as locked_vm */
+ return ret; /* 0 or negative error code */
}
/*
@@ -289,7 +261,7 @@ long mlock_vma_pages_range(struct vm_area_struct *vma,
is_vm_hugetlb_page(vma) ||
vma == get_gate_vma(current))) {
- __mlock_vma_pages_range(vma, start, end, 1);
+ __mlock_vma_pages_range(vma, start, end);
/* Hide errors from mmap() and other callers */
return 0;
@@ -310,7 +282,6 @@ long mlock_vma_pages_range(struct vm_area_struct *vma,
return nr_pages; /* error or pages NOT mlocked */
}
-
/*
* munlock_vma_pages_range() - munlock all pages in the vma range.'
* @vma - vma containing range to be munlock()ed.
@@ -330,10 +301,24 @@ long mlock_vma_pages_range(struct vm_area_struct *vma,
* free them. This will result in freeing mlocked pages.
*/
void munlock_vma_pages_range(struct vm_area_struct *vma,
- unsigned long start, unsigned long end)
+ unsigned long start, unsigned long end)
{
+ unsigned long addr;
+
+ lru_add_drain();
vma->vm_flags &= ~VM_LOCKED;
- __mlock_vma_pages_range(vma, start, end, 0);
+
+ for (addr = start; addr < end; addr += PAGE_SIZE) {
+ struct page *page = follow_page(vma, addr, FOLL_GET);
+ if (page) {
+ lock_page(page);
+ if (page->mapping)
+ munlock_vma_page(page);
+ unlock_page(page);
+ put_page(page);
+ }
+ cond_resched();
+ }
}
/*
@@ -400,18 +385,14 @@ static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev,
* It's okay if try_to_unmap_one unmaps a page just after we
* set VM_LOCKED, __mlock_vma_pages_range will bring it back.
*/
- vma->vm_flags = newflags;
if (lock) {
- ret = __mlock_vma_pages_range(vma, start, end, 1);
-
- if (ret > 0) {
- mm->locked_vm -= ret;
- ret = 0;
- } else
- ret = __mlock_posix_error_return(ret); /* translate if needed */
+ vma->vm_flags = newflags;
+ ret = __mlock_vma_pages_range(vma, start, end);
+ if (ret < 0)
+ ret = __mlock_posix_error_return(ret);
} else {
- __mlock_vma_pages_range(vma, start, end, 0);
+ munlock_vma_pages_range(vma, start, end);
}
out: