---

yaml
---
r: 331392
b: refs/heads/master
c: ec8fc87
h: refs/heads/master
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: eb5e89fc70bb3f115b3206ed0c57d3aba1fdd155
+refs/heads/master: ec8fc870156b2b144f55b6a5a7d135018f04b30e

trunk/drivers/char/virtio_console.c

@@ -794,7 +794,7 @@ static int pipe_to_sg(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
 			struct splice_desc *sd)
 {
 	struct sg_list *sgl = sd->u.data;
-	unsigned int len = 0;
+	unsigned int offset, len;
 
 	if (sgl->n == MAX_SPLICE_PAGES)
 		return 0;
@@ -807,9 +807,31 @@ static int pipe_to_sg(struct pipe_inode_info *pipe, struct pipe_buffer *buf,
 
 		len = min(buf->len, sd->len);
 		sg_set_page(&(sgl->sg[sgl->n]), buf->page, len, buf->offset);
-		sgl->n++;
-		sgl->len += len;
+	} else {
+		/* Failback to copying a page */
+		struct page *page = alloc_page(GFP_KERNEL);
+		char *src = buf->ops->map(pipe, buf, 1);
+		char *dst;
+
+		if (!page)
+			return -ENOMEM;
+		dst = kmap(page);
+
+		offset = sd->pos & ~PAGE_MASK;
+
+		len = sd->len;
+		if (len + offset > PAGE_SIZE)
+			len = PAGE_SIZE - offset;
+
+		memcpy(dst + offset, src + buf->offset, len);
+
+		kunmap(page);
+		buf->ops->unmap(pipe, buf, src);
+
+		sg_set_page(&(sgl->sg[sgl->n]), page, len, offset);
 	}
+	sgl->n++;
+	sgl->len += len;
 
 	return len;
 }