Get rid of two nested loops over nr_pages and other random cleanups.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
mm/gup.c | 148 +++++++++++++++++++++++++++++++--------------------------------
1 file changed, 72 insertions(+), 76 deletions(-)
diff --git a/mm/gup.c b/mm/gup.c
index 6ee33a6744af..6f5c5944f1a4 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -370,9 +370,10 @@ long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
unsigned int gup_flags, struct page **pages,
struct vm_area_struct **vmas, int *nonblocking)
{
- long i;
+ long i = 0;
unsigned long vm_flags;
unsigned int page_mask;
+ struct vm_area_struct *vma = NULL;
if (!nr_pages)
return 0;
@@ -400,88 +401,83 @@ long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
if (!(gup_flags & FOLL_FORCE))
gup_flags |= FOLL_NUMA;
- i = 0;
-
do {
- struct vm_area_struct *vma;
-
- vma = find_extend_vma(mm, start);
- if (!vma && in_gate_area(mm, start)) {
- int ret;
- ret = get_gate_page(mm, start & PAGE_MASK, gup_flags,
- &vma, pages ? &pages[i] : NULL);
- if (ret)
- return i ? : ret;
- page_mask = 0;
- goto next_page;
- }
-
- if (!vma ||
- (vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
- !(vm_flags & vma->vm_flags))
- return i ? : -EFAULT;
-
- if (is_vm_hugetlb_page(vma)) {
- i = follow_hugetlb_page(mm, vma, pages, vmas,
- &start, &nr_pages, i, gup_flags);
- continue;
- }
-
- do {
- struct page *page;
- unsigned int foll_flags = gup_flags;
- unsigned int page_increm;
+ struct page *page;
+ unsigned int foll_flags = gup_flags;
+ unsigned int page_increm;
+
+ /* first iteration or cross vma bound */
+ if (!vma || start >= vma->vm_end) {
+ vma = find_extend_vma(mm, start);
+ if (!vma && in_gate_area(mm, start)) {
+ int ret;
+ ret = get_gate_page(mm, start & PAGE_MASK,
+ gup_flags, &vma,
+ pages ? &pages[i] : NULL);
+ if (ret)
+ return i ? : ret;
+ page_mask = 0;
+ goto next_page;
+ }
- /*
- * If we have a pending SIGKILL, don't keep faulting
- * pages and potentially allocating memory.
- */
- if (unlikely(fatal_signal_pending(current)))
- return i ? i : -ERESTARTSYS;
+ if (!vma || (vma->vm_flags & (VM_IO | VM_PFNMAP)) ||
+ !(vm_flags & vma->vm_flags))
+ return i ? : -EFAULT;
- cond_resched();
- while (!(page = follow_page_mask(vma, start,
- foll_flags, &page_mask))) {
- int ret;
- ret = faultin_page(tsk, vma, start, &foll_flags,
- nonblocking);
- switch (ret) {
- case 0:
- break;
- case -EFAULT:
- case -ENOMEM:
- case -EHWPOISON:
- return i ? i : ret;
- case -EBUSY:
- return i;
- case -ENOENT:
- goto next_page;
- default:
- BUILD_BUG();
- }
- cond_resched();
+ if (is_vm_hugetlb_page(vma)) {
+ i = follow_hugetlb_page(mm, vma, pages, vmas,
+ &start, &nr_pages, i,
+ gup_flags);
+ continue;
}
- if (IS_ERR(page))
- return i ? i : PTR_ERR(page);
- if (pages) {
- pages[i] = page;
+ }
- flush_anon_page(vma, page, start);
- flush_dcache_page(page);
- page_mask = 0;
+ /*
+ * If we have a pending SIGKILL, don't keep faulting pages and
+ * potentially allocating memory.
+ */
+ if (unlikely(fatal_signal_pending(current)))
+ return i ? i : -ERESTARTSYS;
+retry:
+ cond_resched();
+ page = follow_page_mask(vma, start, foll_flags, &page_mask);
+ if (!page) {
+ int ret;
+ ret = faultin_page(tsk, vma, start, &foll_flags,
+ nonblocking);
+ switch (ret) {
+ case 0:
+ goto retry;
+ case -EFAULT:
+ case -ENOMEM:
+ case -EHWPOISON:
+ return i ? i : ret;
+ case -EBUSY:
+ return i;
+ case -ENOENT:
+ goto next_page;
}
+ BUILD_BUG();
+ }
+ if (IS_ERR(page))
+ return i ? i : PTR_ERR(page);
+ if (pages) {
+ pages[i] = page;
+ flush_anon_page(vma, page, start);
+ flush_dcache_page(page);
+ page_mask = 0;
+ }
next_page:
- if (vmas) {
- vmas[i] = vma;
- page_mask = 0;
- }
- page_increm = 1 + (~(start >> PAGE_SHIFT) & page_mask);
- if (page_increm > nr_pages)
- page_increm = nr_pages;
- i += page_increm;
- start += page_increm * PAGE_SIZE;
- nr_pages -= page_increm;
- } while (nr_pages && start < vma->vm_end);
+ if (vmas) {
+ vmas[i] = vma;
+ page_mask = 0;
+ }
+ page_increm = 1 + (~(start >> PAGE_SHIFT) & page_mask);
+ if (page_increm > nr_pages)
+ page_increm = nr_pages;
+ i += page_increm;
+ start += page_increm * PAGE_SIZE;
+ nr_pages -= page_increm;
} while (nr_pages);
return i;
}
--
1.9.1
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>