2 files changed, 71 insertions, 0 deletions

diff --git a/include/linux/uio.h b/include/linux/uio.h
index 71880299ed48..1f4a37f1f025 100644
--- a/include/linux/uio.h
+++ b/include/linux/uio.h
@@ -139,4 +139,18 @@ static inline void iov_iter_reexpand(struct iov_iter *i, size_t count)
 size_t csum_and_copy_to_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
 size_t csum_and_copy_from_iter(void *addr, size_t bytes, __wsum *csum, struct iov_iter *i);
 
+int import_iovec(int type, const struct iovec __user * uvector,
+                 unsigned nr_segs, unsigned fast_segs,
+                 struct iovec **iov, struct iov_iter *i);
+
+#ifdef CONFIG_COMPAT
+struct compat_iovec;
+int compat_import_iovec(int type, const struct compat_iovec __user * uvector,
+                 unsigned nr_segs, unsigned fast_segs,
+                 struct iovec **iov, struct iov_iter *i);
+#endif
+
+int import_single_range(int type, void __user *buf, size_t len,
+                 struct iovec *iov, struct iov_iter *i);
+
 #endif
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index 9d96e283520c..fc6e33f6b7f3 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -766,3 +766,60 @@ const void *dup_iter(struct iov_iter *new, struct iov_iter *old, gfp_t flags)
                                    flags);
 }
 EXPORT_SYMBOL(dup_iter);
+
+int import_iovec(int type, const struct iovec __user * uvector,
+                 unsigned nr_segs, unsigned fast_segs,
+                 struct iovec **iov, struct iov_iter *i)
+{
+        ssize_t n;
+        struct iovec *p;
+        n = rw_copy_check_uvector(type, uvector, nr_segs, fast_segs,
+                                  *iov, &p);
+        if (n < 0) {
+                if (p != *iov)
+                        kfree(p);
+                *iov = NULL;
+                return n;
+        }
+        iov_iter_init(i, type, p, nr_segs, n);
+        *iov = p == *iov ? NULL : p;
+        return 0;
+}
+EXPORT_SYMBOL(import_iovec);
+
+#ifdef CONFIG_COMPAT
+#include <linux/compat.h>
+
+int compat_import_iovec(int type, const struct compat_iovec __user * uvector,
+                 unsigned nr_segs, unsigned fast_segs,
+                 struct iovec **iov, struct iov_iter *i)
+{
+        ssize_t n;
+        struct iovec *p;
+        n = compat_rw_copy_check_uvector(type, uvector, nr_segs, fast_segs,
+                                  *iov, &p);
+        if (n < 0) {
+                if (p != *iov)
+                        kfree(p);
+                *iov = NULL;
+                return n;
+        }
+        iov_iter_init(i, type, p, nr_segs, n);
+        *iov = p == *iov ? NULL : p;
+        return 0;
+}
+#endif
+
+int import_single_range(int rw, void __user *buf, size_t len,
+                 struct iovec *iov, struct iov_iter *i)
+{
+        if (len > MAX_RW_COUNT)
+                len = MAX_RW_COUNT;
+        if (unlikely(!access_ok(!rw, buf, len)))
+                return -EFAULT;
+
+        iov->iov_base = buf;
+        iov->iov_len = len;
+        iov_iter_init(i, rw, iov, 1, len);
+        return 0;
+}