}
EXPORT_SYMBOL(strndup_user);
+/**
+ * memdup_user_nul - duplicate memory region from user space and NUL-terminate
+ *
+ * @src: source address in user space
+ * @len: number of bytes to copy
+ *
+ * Returns an ERR_PTR() on failure.
+ */
+void *memdup_user_nul(const void __user *src, size_t len)
+{
+ char *p;
+
+ /*
+ * Always use GFP_KERNEL, since copy_from_user() can sleep and
+ * cause pagefault, which makes it pointless to use GFP_NOFS
+ * or GFP_ATOMIC.
+ */
+ p = kmalloc_track_caller(len + 1, GFP_KERNEL);
+ if (!p)
+ return ERR_PTR(-ENOMEM);
+
+ if (copy_from_user(p, src, len)) {
+ kfree(p);
+ return ERR_PTR(-EFAULT);
+ }
+ p[len] = '\0';
+
+ return p;
+}
+EXPORT_SYMBOL(memdup_user_nul);
+
void __vma_link_list(struct mm_struct *mm, struct vm_area_struct *vma,
struct vm_area_struct *prev, struct rb_node *rb_parent)
{
struct address_space *page_mapping(struct page *page)
{
- unsigned long mapping;
+ struct address_space *mapping;
+
+ page = compound_head(page);
/* This happens if someone calls flush_dcache_page on slab page */
if (unlikely(PageSlab(page)))
return swap_address_space(entry);
}
- mapping = (unsigned long)page->mapping;
- if (mapping & PAGE_MAPPING_FLAGS)
+ mapping = page->mapping;
+ if ((unsigned long)mapping & PAGE_MAPPING_FLAGS)
return NULL;
- return page->mapping;
+ return mapping;
+}
+
+/* Slow path of page_mapcount() for compound pages */
+int __page_mapcount(struct page *page)
+{
+ int ret;
+
+ ret = atomic_read(&page->_mapcount) + 1;
+ page = compound_head(page);
+ ret += atomic_read(compound_mapcount_ptr(page)) + 1;
+ if (PageDoubleMap(page))
+ ret--;
+ return ret;
}
+EXPORT_SYMBOL_GPL(__page_mapcount);
int overcommit_ratio_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp,