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[188.28.125.106]) by smtp.gmail.com with ESMTPSA id t21-20020a05640203d500b0043573c59ea0sm9758451edw.90.2022.06.28.12.00.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 28 Jun 2022 12:00:02 -0700 (PDT) From: Pavel Begunkov To: io-uring@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Cc: "David S . Miller" , Jakub Kicinski , Jonathan Lemon , Willem de Bruijn , Jens Axboe , kernel-team@fb.com, Pavel Begunkov Subject: [RFC net-next v3 09/29] ipv4/udp: support zc with managed data Date: Tue, 28 Jun 2022 19:56:31 +0100 Message-Id: <1904009c2af0197b922e413254ef2ff2c527f743.1653992701.git.asml.silence@gmail.com> X-Mailer: git-send-email 2.36.1 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org X-Patchwork-State: RFC Teach ipv4/udp about managed data. Make it recognise and use msg->msg_ubuf, and also set/propagate SKBFL_MANAGED_FRAG_REFS down to skb_zerocopy_iter_dgram(). Signed-off-by: Pavel Begunkov --- net/ipv4/ip_output.c | 57 +++++++++++++++++++++++++++++++++----------- 1 file changed, 43 insertions(+), 14 deletions(-) diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index 581d1e233260..3fd1bf675598 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -1017,18 +1017,35 @@ static int __ip_append_data(struct sock *sk, (!exthdrlen || (rt->dst.dev->features & NETIF_F_HW_ESP_TX_CSUM))) csummode = CHECKSUM_PARTIAL; - if (flags & MSG_ZEROCOPY && length && sock_flag(sk, SOCK_ZEROCOPY)) { - uarg = msg_zerocopy_realloc(sk, length, skb_zcopy(skb)); - if (!uarg) - return -ENOBUFS; - extra_uref = !skb_zcopy(skb); /* only ref on new uarg */ - if (rt->dst.dev->features & NETIF_F_SG && - csummode == CHECKSUM_PARTIAL) { - paged = true; - zc = true; - } else { - uarg->zerocopy = 0; - skb_zcopy_set(skb, uarg, &extra_uref); + if ((flags & MSG_ZEROCOPY) && length) { + struct msghdr *msg = from; + + if (getfrag == ip_generic_getfrag && msg->msg_ubuf) { + if (skb_zcopy(skb) && msg->msg_ubuf != skb_zcopy(skb)) + return -EINVAL; + + /* Leave uarg NULL if can't zerocopy, callers should + * be able to handle it. + */ + if ((rt->dst.dev->features & NETIF_F_SG) && + csummode == CHECKSUM_PARTIAL) { + paged = true; + zc = true; + uarg = msg->msg_ubuf; + } + } else if (sock_flag(sk, SOCK_ZEROCOPY)) { + uarg = msg_zerocopy_realloc(sk, length, skb_zcopy(skb)); + if (!uarg) + return -ENOBUFS; + extra_uref = !skb_zcopy(skb); /* only ref on new uarg */ + if (rt->dst.dev->features & NETIF_F_SG && + csummode == CHECKSUM_PARTIAL) { + paged = true; + zc = true; + } else { + uarg->zerocopy = 0; + skb_zcopy_set(skb, uarg, &extra_uref); + } } } @@ -1192,13 +1209,14 @@ static int __ip_append_data(struct sock *sk, err = -EFAULT; goto error; } - } else if (!uarg || !uarg->zerocopy) { + } else if (!zc) { int i = skb_shinfo(skb)->nr_frags; err = -ENOMEM; if (!sk_page_frag_refill(sk, pfrag)) goto error; + skb_zcopy_downgrade_managed(skb); if (!skb_can_coalesce(skb, i, pfrag->page, pfrag->offset)) { err = -EMSGSIZE; @@ -1223,7 +1241,18 @@ static int __ip_append_data(struct sock *sk, skb->truesize += copy; wmem_alloc_delta += copy; } else { - err = skb_zerocopy_iter_dgram(skb, from, copy); + struct msghdr *msg = from; + + if (!skb_shinfo(skb)->nr_frags) { + if (msg->msg_managed_data) + skb_shinfo(skb)->flags |= SKBFL_MANAGED_FRAG_REFS; + } else { + /* appending, don't mix managed and unmanaged */ + if (!msg->msg_managed_data) + skb_zcopy_downgrade_managed(skb); + } + + err = skb_zerocopy_iter_dgram(skb, msg, copy); if (err < 0) goto error; }