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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Tariq Toukan , Simon Horman , Steffen Klassert , Herbert Xu , Neal Cardwell , Kuniyuki Iwashima , John Fastabend , Sabrina Dubroca , Eric Biggers , Kees Cook , Aleksandr Loktionov , Petr Machata , "=?UTF-8?q?Uwe=20Kleine-K=C3=B6nig=20=28The=20Capable=20Hub=29?=" , Jakub Raczynski , Wang Zhan , Willem de Bruijn Content-Type: text/plain; charset="UTF-8" While napi_pp_put_page() releases a page_pool pp_ref_count reference on a netmem, no symmetric helper existed to acquire one, forcing callers like tcp_recvmsg_dmabuf() to open-code atomic_long_inc() on niov->desc.pp_ref_count. Add napi_pp_get_page() to pair symmetrically with napi_pp_put_page(), and use WARN_ON_ONCE(!napi_pp_get_page(netmem)) in tcp_recvmsg_dmabuf() to match WARN_ON_ONCE(!napi_pp_put_page(netmem)) in tcp_release_user_frags(). Assisted-by: LLM Signed-off-by: Mina Almasry --- include/linux/skbuff_ref.h | 2 ++ net/core/skbuff.c | 31 +++++++++++++++++++++++++++++++ net/ipv4/tcp.c | 6 ++++-- 3 files changed, 37 insertions(+), 2 deletions(-) diff --git a/include/linux/skbuff_ref.h b/include/linux/skbuff_ref.h index 05c8486bafac8..0441c220fdbdf 100644 --- a/include/linux/skbuff_ref.h +++ b/include/linux/skbuff_ref.h @@ -9,6 +9,8 @@ #include +bool napi_pp_get_page(netmem_ref netmem); + /** * __skb_frag_ref - take an addition reference on a paged fragment. * @frag: the paged fragment diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 23a40e1ec2b15..76a42c60508d9 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -1026,6 +1026,15 @@ int skb_cow_data_for_xdp(struct page_pool *pool, struct sk_buff **pskb, EXPORT_SYMBOL(skb_cow_data_for_xdp); #if IS_ENABLED(CONFIG_PAGE_POOL) +/** + * napi_pp_put_page - release a page_pool reference on a netmem + * @netmem: netmem to unreference + * + * Drops a page_pool reference (pp_ref_count) on @netmem if it belongs to a + * page_pool. Counterpart to napi_pp_get_page(). + * + * Return: true if @netmem belongs to a page_pool, false otherwise. + */ bool napi_pp_put_page(netmem_ref netmem) { netmem = netmem_compound_head(netmem); @@ -1038,6 +1047,28 @@ bool napi_pp_put_page(netmem_ref netmem) return true; } EXPORT_SYMBOL(napi_pp_put_page); + +/** + * napi_pp_get_page - acquire a page_pool reference on a netmem + * @netmem: netmem to reference + * + * Acquires a page_pool reference (pp_ref_count) on @netmem if it belongs to a + * page_pool. Counterpart to napi_pp_put_page(). + * + * Return: true if @netmem belongs to a page_pool, false otherwise. + */ +bool napi_pp_get_page(netmem_ref netmem) +{ + netmem = netmem_compound_head(netmem); + + if (unlikely(!netmem_is_pp(netmem))) + return false; + + page_pool_ref_netmem(netmem); + + return true; +} +EXPORT_SYMBOL(napi_pp_get_page); #endif static bool skb_pp_recycle(struct sk_buff *skb, void *data) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index f4c9101e5996a..99d7237a623d8 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -254,6 +254,7 @@ #include #include #include +#include #include #include #include @@ -2559,6 +2560,7 @@ static int tcp_recvmsg_dmabuf(struct sock *sk, const struct sk_buff *skb, */ for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) { skb_frag_t *frag = &skb_shinfo(skb)->frags[i]; + netmem_ref netmem = skb_frag_netmem(frag); struct net_iov *niov; u64 frag_offset; int end; @@ -2612,8 +2614,8 @@ static int tcp_recvmsg_dmabuf(struct sock *sk, const struct sk_buff *skb, if (err) goto out; - atomic_long_inc(&niov->desc.pp_ref_count); - tcp_xa_pool.netmems[tcp_xa_pool.idx++] = skb_frag_netmem(frag); + WARN_ON_ONCE(!napi_pp_get_page(netmem)); + tcp_xa_pool.netmems[tcp_xa_pool.idx++] = netmem; sent += copy; -- 2.56.0.212.g129ede20d9-goog