If sendmsg() is passed MSG_SPLICE_PAGES and is given a buffer that contains
some data that's resident in the slab, copy/coalesce it rather than
returning EIO.
Signed-off-by: David Howells <[email protected]>
cc: Eric Dumazet <[email protected]>
cc: "David S. Miller" <[email protected]>
cc: David Ahern <[email protected]>
cc: Jakub Kicinski <[email protected]>
cc: Paolo Abeni <[email protected]>
cc: Jens Axboe <[email protected]>
cc: Matthew Wilcox <[email protected]>
cc: [email protected]
---
include/linux/skbuff.h | 3 +++
net/core/skbuff.c | 33 ++++++++++++++++++++++++++++++---
2 files changed, 33 insertions(+), 3 deletions(-)
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index e11a765fe7fa..11d98990f5f1 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -5084,6 +5084,9 @@ static inline void skb_mark_for_recycle(struct sk_buff *skb)
#endif
}
+ssize_t skb_splice_from_iter(struct sk_buff *skb, struct iov_iter *iter,
+ ssize_t maxsize, gfp_t gfp);
+
ssize_t skb_splice_from_iter(struct sk_buff *skb, struct iov_iter *iter,
ssize_t maxsize, gfp_t gfp);
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index c2840b0dcad9..a16499b9942b 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -6927,17 +6927,44 @@ ssize_t skb_splice_from_iter(struct sk_buff *skb, struct iov_iter *iter,
break;
}
+ if (space == 0 &&
+ !skb_can_coalesce(skb, skb_shinfo(skb)->nr_frags,
+ pages[0], off)) {
+ iov_iter_revert(iter, len);
+ break;
+ }
+
i = 0;
do {
struct page *page = pages[i++];
size_t part = min_t(size_t, PAGE_SIZE - off, len);
-
- ret = -EIO;
- if (WARN_ON_ONCE(!sendpage_ok(page)))
+ bool put = false;
+
+ if (PageSlab(page)) {
+ const void *p;
+ void *q;
+
+ p = kmap_local_page(page);
+ q = page_frag_memdup(NULL, p + off, part, gfp,
+ ULONG_MAX);
+ kunmap_local(p);
+ if (!q) {
+ iov_iter_revert(iter, len);
+ ret = -ENOMEM;
+ goto out;
+ }
+ page = virt_to_page(q);
+ off = offset_in_page(q);
+ put = true;
+ } else if (WARN_ON_ONCE(!sendpage_ok(page))) {
+ ret = -EIO;
goto out;
+ }
ret = skb_append_pagefrags(skb, page, off, part,
frag_limit);
+ if (put)
+ put_page(page);
if (ret < 0) {
iov_iter_revert(iter, len);
goto out;