From e7d2b510165fff6bedc9cca88c071ad846850c74 Mon Sep 17 00:00:00 2001 From: Pavel Begunkov Date: Fri, 23 Sep 2022 17:39:04 +0100 Subject: [PATCH] net: shrink struct ubuf_info We can benefit from a smaller struct ubuf_info, so leave only mandatory fields and let users to decide how they want to extend it. Convert MSG_ZEROCOPY to struct ubuf_info_msgzc and remove duplicated fields. This reduces the size from 48 bytes to just 16. Signed-off-by: Pavel Begunkov Acked-by: Paolo Abeni Signed-off-by: Jakub Kicinski --- include/linux/skbuff.h | 22 ++++------------------ net/core/skbuff.c | 38 +++++++++++++++++++++----------------- net/ipv4/ip_output.c | 2 +- net/ipv4/tcp.c | 2 +- net/ipv6/ip6_output.c | 2 +- 5 files changed, 28 insertions(+), 38 deletions(-) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index fd7dcb977fdf..920eb6413fee 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -533,25 +533,8 @@ enum { struct ubuf_info { void (*callback)(struct sk_buff *, struct ubuf_info *, bool zerocopy_success); - union { - struct { - unsigned long desc; - void *ctx; - }; - struct { - u32 id; - u16 len; - u16 zerocopy:1; - u32 bytelen; - }; - }; refcount_t refcnt; u8 flags; - - struct mmpin { - struct user_struct *user; - unsigned int num_pg; - } mmp; }; struct ubuf_info_msgzc { @@ -570,7 +553,10 @@ struct ubuf_info_msgzc { }; }; - struct mmpin mmp; + struct mmpin { + struct user_struct *user; + unsigned int num_pg; + } mmp; }; #define skb_uarg(SKB) ((struct ubuf_info *)(skb_shinfo(SKB)->destructor_arg)) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index f1b8b20fc20b..bbcfb1c7f59e 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -1188,7 +1188,7 @@ EXPORT_SYMBOL_GPL(mm_unaccount_pinned_pages); static struct ubuf_info *msg_zerocopy_alloc(struct sock *sk, size_t size) { - struct ubuf_info *uarg; + struct ubuf_info_msgzc *uarg; struct sk_buff *skb; WARN_ON_ONCE(!in_task()); @@ -1206,19 +1206,19 @@ static struct ubuf_info *msg_zerocopy_alloc(struct sock *sk, size_t size) return NULL; } - uarg->callback = msg_zerocopy_callback; + uarg->ubuf.callback = msg_zerocopy_callback; uarg->id = ((u32)atomic_inc_return(&sk->sk_zckey)) - 1; uarg->len = 1; uarg->bytelen = size; uarg->zerocopy = 1; - uarg->flags = SKBFL_ZEROCOPY_FRAG | SKBFL_DONT_ORPHAN; - refcount_set(&uarg->refcnt, 1); + uarg->ubuf.flags = SKBFL_ZEROCOPY_FRAG | SKBFL_DONT_ORPHAN; + refcount_set(&uarg->ubuf.refcnt, 1); sock_hold(sk); - return uarg; + return &uarg->ubuf; } -static inline struct sk_buff *skb_from_uarg(struct ubuf_info *uarg) +static inline struct sk_buff *skb_from_uarg(struct ubuf_info_msgzc *uarg) { return container_of((void *)uarg, struct sk_buff, cb); } @@ -1227,6 +1227,7 @@ struct ubuf_info *msg_zerocopy_realloc(struct sock *sk, size_t size, struct ubuf_info *uarg) { if (uarg) { + struct ubuf_info_msgzc *uarg_zc; const u32 byte_limit = 1 << 19; /* limit to a few TSO */ u32 bytelen, next; @@ -1242,8 +1243,9 @@ struct ubuf_info *msg_zerocopy_realloc(struct sock *sk, size_t size, return NULL; } - bytelen = uarg->bytelen + size; - if (uarg->len == USHRT_MAX - 1 || bytelen > byte_limit) { + uarg_zc = uarg_to_msgzc(uarg); + bytelen = uarg_zc->bytelen + size; + if (uarg_zc->len == USHRT_MAX - 1 || bytelen > byte_limit) { /* TCP can create new skb to attach new uarg */ if (sk->sk_type == SOCK_STREAM) goto new_alloc; @@ -1251,11 +1253,11 @@ struct ubuf_info *msg_zerocopy_realloc(struct sock *sk, size_t size, } next = (u32)atomic_read(&sk->sk_zckey); - if ((u32)(uarg->id + uarg->len) == next) { - if (mm_account_pinned_pages(&uarg->mmp, size)) + if ((u32)(uarg_zc->id + uarg_zc->len) == next) { + if (mm_account_pinned_pages(&uarg_zc->mmp, size)) return NULL; - uarg->len++; - uarg->bytelen = bytelen; + uarg_zc->len++; + uarg_zc->bytelen = bytelen; atomic_set(&sk->sk_zckey, ++next); /* no extra ref when appending to datagram (MSG_MORE) */ @@ -1291,7 +1293,7 @@ static bool skb_zerocopy_notify_extend(struct sk_buff *skb, u32 lo, u16 len) return true; } -static void __msg_zerocopy_callback(struct ubuf_info *uarg) +static void __msg_zerocopy_callback(struct ubuf_info_msgzc *uarg) { struct sk_buff *tail, *skb = skb_from_uarg(uarg); struct sock_exterr_skb *serr; @@ -1344,19 +1346,21 @@ static void __msg_zerocopy_callback(struct ubuf_info *uarg) void msg_zerocopy_callback(struct sk_buff *skb, struct ubuf_info *uarg, bool success) { - uarg->zerocopy = uarg->zerocopy & success; + struct ubuf_info_msgzc *uarg_zc = uarg_to_msgzc(uarg); + + uarg_zc->zerocopy = uarg_zc->zerocopy & success; if (refcount_dec_and_test(&uarg->refcnt)) - __msg_zerocopy_callback(uarg); + __msg_zerocopy_callback(uarg_zc); } EXPORT_SYMBOL_GPL(msg_zerocopy_callback); void msg_zerocopy_put_abort(struct ubuf_info *uarg, bool have_uref) { - struct sock *sk = skb_from_uarg(uarg)->sk; + struct sock *sk = skb_from_uarg(uarg_to_msgzc(uarg))->sk; atomic_dec(&sk->sk_zckey); - uarg->len--; + uarg_to_msgzc(uarg)->len--; if (have_uref) msg_zerocopy_callback(NULL, uarg, true); diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index 8201cd423ff9..1ae83ad629b2 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -1043,7 +1043,7 @@ static int __ip_append_data(struct sock *sk, paged = true; zc = true; } else { - uarg->zerocopy = 0; + uarg_to_msgzc(uarg)->zerocopy = 0; skb_zcopy_set(skb, uarg, &extra_uref); } } diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 5702ca9b952d..a109a4cb1e47 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1239,7 +1239,7 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size) } zc = sk->sk_route_caps & NETIF_F_SG; if (!zc) - uarg->zerocopy = 0; + uarg_to_msgzc(uarg)->zerocopy = 0; } } diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index a60176e913a8..e19507614f64 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1567,7 +1567,7 @@ static int __ip6_append_data(struct sock *sk, paged = true; zc = true; } else { - uarg->zerocopy = 0; + uarg_to_msgzc(uarg)->zerocopy = 0; skb_zcopy_set(skb, uarg, &extra_uref); } }