+int kvm_get_user_page_io(struct task_struct *tsk, struct mm_struct *mm,
+ unsigned long addr, bool write_fault,
+ struct page **pagep)
+{
+ int npages;
+ int locked = 1;
+ int flags = FOLL_TOUCH | FOLL_HWPOISON |
+ (pagep ? FOLL_GET : 0) |
+ (write_fault ? FOLL_WRITE : 0);
+
+ /*
+ * If retrying the fault, we get here *not* having allowed the filemap
+ * to wait on the page lock. We should now allow waiting on the IO with
+ * the mmap semaphore released.
+ */
+ down_read(&mm->mmap_sem);
+ npages = __get_user_pages(tsk, mm, addr, 1, flags, pagep, NULL,
+ &locked);
+ if (!locked) {
+ VM_BUG_ON(npages != -EBUSY);
+
+ if (!pagep)
+ return 0;
+
+ /*
+ * The previous call has now waited on the IO. Now we can
+ * retry and complete. Pass TRIED to ensure we do not re
+ * schedule async IO (see e.g. filemap_fault).
+ */
+ down_read(&mm->mmap_sem);
+ npages = __get_user_pages(tsk, mm, addr, 1, flags | FOLL_TRIED,
+ pagep, NULL, NULL);
+ }
+ up_read(&mm->mmap_sem);
+ return npages;
+}
+