iov: add import_ubuf()

Like import_single_range(), but for ITER_UBUF.

Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

1 files changed, 11 insertions, 0 deletions

diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index f9a3ff37ecd1..f036760b66e2 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -1877,6 +1877,17 @@ int import_single_range(int rw, void __user *buf, size_t len,
 }
 EXPORT_SYMBOL(import_single_range);
 
+int import_ubuf(int rw, void __user *buf, size_t len, struct iov_iter *i)
+{
+	if (len > MAX_RW_COUNT)
+		len = MAX_RW_COUNT;
+	if (unlikely(!access_ok(buf, len)))
+		return -EFAULT;
+
+	iov_iter_ubuf(i, rw, buf, len);
+	return 0;
+}
+
 /**
  * iov_iter_restore() - Restore a &struct iov_iter to the same state as when
  *     iov_iter_save_state() was called.