diff options
Diffstat (limited to 'mm/hugetlb.c')
| -rw-r--r-- | mm/hugetlb.c | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 75d8bd7e8798..6b03cd9b6d37 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -3984,6 +3984,7 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long vaddr = *position; unsigned long remainder = *nr_pages; struct hstate *h = hstate_vma(vma); + int err = -EFAULT; while (vaddr < vma->vm_end && remainder) { pte_t *pte; @@ -4055,6 +4056,19 @@ long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT; page = pte_page(huge_ptep_get(pte)); + + /* + * Instead of doing 'try_get_page()' below in the same_page + * loop, just check the count once here. + */ + if (unlikely(page_count(page) <= 0)) { + if (pages) { + spin_unlock(ptl); + remainder = 0; + err = -ENOMEM; + break; + } + } same_page: if (pages) { pages[i] = mem_map_offset(page, pfn_offset); @@ -4081,7 +4095,7 @@ same_page: *nr_pages = remainder; *position = vaddr; - return i ? i : -EFAULT; + return i ? i : err; } #ifndef __HAVE_ARCH_FLUSH_HUGETLB_TLB_RANGE |