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authorPavel Begunkov <asml.silence@gmail.com>2024-04-19 14:08:40 +0300
committerJakub Kicinski <kuba@kernel.org>2024-04-23 02:21:59 +0300
commit65bada80dec1f2108a751644773b2120bd789934 (patch)
tree20ad5053474b841f7c71d74f627c41d1bbd1a27f /net
parent7ab4f16f9e2440e797eae88812f800458e5879d2 (diff)
downloadlinux-65bada80dec1f2108a751644773b2120bd789934.tar.xz
net: add callback for setting a ubuf_info to skb
At the moment an skb can only have one ubuf_info associated with it, which might be a performance problem for zerocopy sends in cases like TCP via io_uring. Add a callback for assigning ubuf_info to skb, this way we will implement smarter assignment later like linking ubuf_info together. Note, it's an optional callback, which should be compatible with skb_zcopy_set(), that's because the net stack might potentially decide to clone an skb and take another reference to ubuf_info whenever it wishes. Also, a correct implementation should always be able to bind to an skb without prior ubuf_info, otherwise we could end up in a situation when the send would not be able to progress. Reviewed-by: Jens Axboe <axboe@kernel.dk> Reviewed-by: David Ahern <dsahern@kernel.org> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Reviewed-by: Willem de Bruijn <willemb@google.com> Link: https://lore.kernel.org/all/b7918aadffeb787c84c9e72e34c729dc04f3a45d.1713369317.git.asml.silence@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
-rw-r--r--net/core/skbuff.c20
1 files changed, 14 insertions, 6 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 9d36750459f3..4a0c10685cd2 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1880,11 +1880,18 @@ int skb_zerocopy_iter_stream(struct sock *sk, struct sk_buff *skb,
struct ubuf_info *orig_uarg = skb_zcopy(skb);
int err, orig_len = skb->len;
- /* An skb can only point to one uarg. This edge case happens when
- * TCP appends to an skb, but zerocopy_realloc triggered a new alloc.
- */
- if (orig_uarg && uarg != orig_uarg)
- return -EEXIST;
+ if (uarg->ops->link_skb) {
+ err = uarg->ops->link_skb(skb, uarg);
+ if (err)
+ return err;
+ } else {
+ /* An skb can only point to one uarg. This edge case happens
+ * when TCP appends to an skb, but zerocopy_realloc triggered
+ * a new alloc.
+ */
+ if (orig_uarg && uarg != orig_uarg)
+ return -EEXIST;
+ }
err = __zerocopy_sg_from_iter(msg, sk, skb, &msg->msg_iter, len);
if (err == -EFAULT || (err == -EMSGSIZE && skb->len == orig_len)) {
@@ -1898,7 +1905,8 @@ int skb_zerocopy_iter_stream(struct sock *sk, struct sk_buff *skb,
return err;
}
- skb_zcopy_set(skb, uarg, NULL);
+ if (!uarg->ops->link_skb)
+ skb_zcopy_set(skb, uarg, NULL);
return skb->len - orig_len;
}
EXPORT_SYMBOL_GPL(skb_zerocopy_iter_stream);