diff options
Diffstat (limited to 'mm/mlock.c')
| -rw-r--r-- | mm/mlock.c | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/mm/mlock.c b/mm/mlock.c index 14645be06e30..145a4258ddbc 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -516,6 +516,7 @@ static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev, int nr_pages; int ret = 0; int lock = !!(newflags & VM_LOCKED); + vm_flags_t old_flags = vma->vm_flags; if (newflags == vma->vm_flags || (vma->vm_flags & VM_SPECIAL) || is_vm_hugetlb_page(vma) || vma == get_gate_vma(current->mm)) @@ -550,6 +551,8 @@ success: nr_pages = (end - start) >> PAGE_SHIFT; if (!lock) nr_pages = -nr_pages; + else if (old_flags & VM_LOCKED) + nr_pages = 0; mm->locked_vm += nr_pages; /* @@ -617,6 +620,45 @@ static int apply_vma_lock_flags(unsigned long start, size_t len, return error; } +/* + * Go through vma areas and sum size of mlocked + * vma pages, as return value. + * Note deferred memory locking case(mlock2(,,MLOCK_ONFAULT) + * is also counted. + * Return value: previously mlocked page counts + */ +static int count_mm_mlocked_page_nr(struct mm_struct *mm, + unsigned long start, size_t len) +{ + struct vm_area_struct *vma; + int count = 0; + + if (mm == NULL) + mm = current->mm; + + vma = find_vma(mm, start); + if (vma == NULL) + vma = mm->mmap; + + for (; vma ; vma = vma->vm_next) { + if (start >= vma->vm_end) + continue; + if (start + len <= vma->vm_start) + break; + 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; + break; + } + count += vma->vm_end - vma->vm_start; + } + } + + return count >> PAGE_SHIFT; +} + static __must_check int do_mlock(unsigned long start, size_t len, vm_flags_t flags) { unsigned long locked; @@ -639,6 +681,16 @@ static __must_check int do_mlock(unsigned long start, size_t len, vm_flags_t fla return -EINTR; locked += current->mm->locked_vm; + if ((locked > lock_limit) && (!capable(CAP_IPC_LOCK))) { + /* + * It is possible that the regions requested intersect with + * previously mlocked areas, that part area in "mm->locked_vm" + * should not be counted to new mlock increment count. So check + * and adjust locked count if necessary. + */ + locked -= count_mm_mlocked_page_nr(current->mm, + start, len); + } /* check against resource limits */ if ((locked <= lock_limit) || capable(CAP_IPC_LOCK)) |