@@ -859,6 +859,9 @@ extern int access_process_vm(struct task_struct *tsk, unsigned long addr, void *
int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
unsigned long start, int nr_pages, int write, int force,
struct page **pages, struct vm_area_struct **vmas);
+int get_user_pages_nowait(struct task_struct *tsk, struct mm_struct *mm,
+ unsigned long start, int nr_pages, int write, int force,
+ struct page **pages, struct vm_area_struct **vmas);
int get_user_pages_fast(unsigned long start, int nr_pages, int write,
struct page **pages);
struct page *get_dump_page(unsigned long addr);
@@ -1416,6 +1419,8 @@ struct page *follow_page(struct vm_area_struct *, unsigned long address,
#define FOLL_GET 0x04 /* do get_page on page */
#define FOLL_DUMP 0x08 /* give error on hole if it would be zero */
#define FOLL_FORCE 0x10 /* get_user_pages read/write w/o permission */
+#define FOLL_RETRY 0x20 /* if disk transfer is needed release mmap_sem and return error */
+#define FOLL_NOWAIT 0x40 /* if disk transfer is needed return error without releasing mmap_sem */
typedef int (*pte_fn_t)(pte_t *pte, pgtable_t token, unsigned long addr,
void *data);
@@ -1443,8 +1443,12 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
int ret;
ret = handle_mm_fault(mm, vma, start,
- (foll_flags & FOLL_WRITE) ?
- FAULT_FLAG_WRITE : 0);
+ ((foll_flags & FOLL_WRITE) ?
+ FAULT_FLAG_WRITE : 0) |
+ ((foll_flags & FOLL_RETRY) ?
+ FAULT_FLAG_ALLOW_RETRY : 0) |
+ ((foll_flags & FOLL_NOWAIT) ?
+ FAULT_FLAG_RETRY_NOWAIT : 0));
if (ret & VM_FAULT_ERROR) {
if (ret & VM_FAULT_OOM)
@@ -1460,6 +1464,9 @@ int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
else
tsk->min_flt++;
+ if (ret & VM_FAULT_RETRY)
+ return i ? i : -EFAULT;
+
/*
* The VM_FAULT_WRITE bit tells us that
* do_wp_page has broken COW when necessary,
@@ -1563,6 +1570,23 @@ int get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
}
EXPORT_SYMBOL(get_user_pages);
+int get_user_pages_nowait(struct task_struct *tsk, struct mm_struct *mm,
+ unsigned long start, int nr_pages, int write, int force,
+ struct page **pages, struct vm_area_struct **vmas)
+{
+ int flags = FOLL_TOUCH | FOLL_RETRY | FOLL_NOWAIT;
+
+ if (pages)
+ flags |= FOLL_GET;
+ if (write)
+ flags |= FOLL_WRITE;
+ if (force)
+ flags |= FOLL_FORCE;
+
+ return __get_user_pages(tsk, mm, start, nr_pages, flags, pages, vmas);
+}
+EXPORT_SYMBOL(get_user_pages_nowait);
+
/**
* get_dump_page() - pin user page in memory while writing it to core dump
* @addr: user address