--- 773793368a791b44e34f5fd561c81d970878cfbf
+++ 7394e9e17534ecb03573e28b2288d06cccf24a32
@@ -365,7 +365,17 @@ __generic_file_splice_read(struct file *
 		 * If the page isn't uptodate, we may need to start io on it
 		 */
 		if (!PageUptodate(page)) {
-			lock_page(page);
+			/*
+			 * If in nonblock mode then dont block on waiting
+			 * for an in-flight io page
+			 */
+			if (flags & SPLICE_F_NONBLOCK) {
+				if (!trylock_page(page)) {
+					error = -EAGAIN;
+					break;
+				}
+			} else
+				lock_page(page);
 
 			/*
 			 * Page was truncated, or invalidated by the
@@ -638,11 +648,9 @@ static int pipe_to_sendpage(struct pipe_
 	ret = buf->ops->confirm(pipe, buf);
 	if (!ret) {
 		more = (sd->flags & SPLICE_F_MORE) || sd->len < sd->total_len;
-		if (file->f_op && file->f_op->sendpage)
-			ret = file->f_op->sendpage(file, buf->page, buf->offset,
-						   sd->len, &pos, more);
-		else
-			ret = -EINVAL;
+
+		ret = file->f_op->sendpage(file, buf->page, buf->offset,
+					   sd->len, &pos, more);
 	}
 
 	return ret;
@@ -1060,9 +1068,8 @@ static long do_splice_from(struct pipe_i
 	if (unlikely(ret < 0))
 		return ret;
 
-	if (out->f_op && out->f_op->splice_write)
-		splice_write = out->f_op->splice_write;
-	else
+	splice_write = out->f_op->splice_write;
+	if (!splice_write)
 		splice_write = default_file_splice_write;
 
 	return splice_write(pipe, out, ppos, len, flags);
@@ -1086,9 +1093,8 @@ static long do_splice_to(struct file *in
 	if (unlikely(ret < 0))
 		return ret;
 
-	if (in->f_op && in->f_op->splice_read)
-		splice_read = in->f_op->splice_read;
-	else
+	splice_read = in->f_op->splice_read;
+	if (!splice_read)
 		splice_read = default_file_splice_read;
 
 	return splice_read(in, ppos, pipe, len, flags);
@@ -1310,8 +1316,7 @@ static long do_splice(struct file *in, l
 		if (off_in)
 			return -ESPIPE;
 		if (off_out) {
-			if (!out->f_op || !out->f_op->llseek ||
-			    out->f_op->llseek == no_llseek)
+			if (out->f_op->llseek == no_llseek)
 				return -EINVAL;
 			if (copy_from_user(&offset, off_out, sizeof(loff_t)))
 				return -EFAULT;
@@ -1331,8 +1336,7 @@ static long do_splice(struct file *in, l
 		if (off_out)
 			return -ESPIPE;
 		if (off_in) {
-			if (!in->f_op || !in->f_op->llseek ||
-			    in->f_op->llseek == no_llseek)
+			if (in->f_op->llseek == no_llseek)
 				return -EINVAL;
 			if (copy_from_user(&offset, off_in, sizeof(loff_t)))
 				return -EFAULT;