Subject: [PATCH] put_page_callback --- drivers/block/drbd/drbd_receiver.c | 2 +- include/linux/mm_types.h | 11 +++++++++ include/linux/net.h | 40 ++++++++++++++++++++++++++++++ include/linux/skbuff.h | 4 +-- net/Kconfig | 12 +++++++++ net/ceph/pagevec.c | 2 +- net/core/skbuff.c | 14 +++++------ net/core/sock.c | 4 +-- net/ipv4/Makefile | 1 + net/ipv4/ip_output.c | 4 +-- net/ipv4/tcp.c | 4 +-- net/ipv4/tcp_zero_copy.c | 50 ++++++++++++++++++++++++++++++++++++++ net/ipv6/ip6_output.c | 2 +- 13 files changed, 132 insertions(+), 18 deletions(-) create mode 100644 net/ipv4/tcp_zero_copy.c diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c index d169b4a..ec913c2 100644 --- a/drivers/block/drbd/drbd_receiver.c +++ b/drivers/block/drbd/drbd_receiver.c @@ -132,7 +132,7 @@ static int page_chain_free(struct page *page) struct page *tmp; int i = 0; page_chain_for_each_safe(page, tmp) { - put_page(page); + net_put_page(page); ++i; } return i; diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 6d34aa2..a536ed7 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -197,6 +197,17 @@ struct page { #ifdef LAST_CPUPID_NOT_IN_PAGE_FLAGS int _last_cpupid; #endif + +#if defined(CONFIG_TCP_ZERO_COPY_TRANSFER_COMPLETION_NOTIFICATION) + /* + * Used to implement support for notification on zero-copy TCP transfer + * completion. It might look as not good to have this field here and + * it's better to have it in struct sk_buff, but it would make the code + * much more complicated and fragile, since all skb then would have to + * contain only pages with the same value in this field. + */ + void *net_priv; +#endif } /* * The struct page can be forced to be double word aligned so that atomic ops diff --git a/include/linux/net.h b/include/linux/net.h index 17d8339..f784384 100644 --- a/include/linux/net.h +++ b/include/linux/net.h @@ -19,6 +19,7 @@ #define _LINUX_NET_H #include +#include #include #include #include /* For O_CLOEXEC and O_NONBLOCK */ @@ -285,6 +286,45 @@ int kernel_sendpage(struct socket *sock, struct page *page, int offset, int kernel_sock_ioctl(struct socket *sock, int cmd, unsigned long arg); int kernel_sock_shutdown(struct socket *sock, enum sock_shutdown_cmd how); +#if defined(CONFIG_TCP_ZERO_COPY_TRANSFER_COMPLETION_NOTIFICATION) +/* Support for notification on zero-copy TCP transfer completion */ +typedef void (*net_get_page_callback_t)(struct page *page); +typedef void (*net_put_page_callback_t)(struct page *page); + +extern net_get_page_callback_t net_get_page_callback; +extern net_put_page_callback_t net_put_page_callback; + +extern int net_set_get_put_page_callbacks( + net_get_page_callback_t get_callback, + net_put_page_callback_t put_callback); + +/* + * See comment for net_set_get_put_page_callbacks() why those functions + * don't need any protection. + */ +static inline void net_get_page(struct page *page) +{ + if (page->net_priv != 0) + net_get_page_callback(page); + get_page(page); +} +static inline void net_put_page(struct page *page) +{ + if (page->net_priv != 0) + net_put_page_callback(page); + put_page(page); +} +#else +static inline void net_get_page(struct page *page) +{ + get_page(page); +} +static inline void net_put_page(struct page *page) +{ + put_page(page); +} +#endif /* CONFIG_TCP_ZERO_COPY_TRANSFER_COMPLETION_NOTIFICATION */ + #define MODULE_ALIAS_NETPROTO(proto) \ MODULE_ALIAS("net-pf-" __stringify(proto)) diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h index 85ab7d7..fb82e86 100644 --- a/include/linux/skbuff.h +++ b/include/linux/skbuff.h @@ -2254,7 +2254,7 @@ static inline struct page *skb_frag_page(const skb_frag_t *frag) */ static inline void __skb_frag_ref(skb_frag_t *frag) { - get_page(skb_frag_page(frag)); + net_get_page(skb_frag_page(frag)); } /** @@ -2277,7 +2277,7 @@ static inline void skb_frag_ref(struct sk_buff *skb, int f) */ static inline void __skb_frag_unref(skb_frag_t *frag) { - put_page(skb_frag_page(frag)); + net_put_page(skb_frag_page(frag)); } /** diff --git a/net/Kconfig b/net/Kconfig index ff9ffc1..a270579 100644 --- a/net/Kconfig +++ b/net/Kconfig @@ -76,6 +76,18 @@ config INET Short answer: say Y. +config TCP_ZERO_COPY_TRANSFER_COMPLETION_NOTIFICATION + bool "TCP/IP zero-copy transfer completion notification" + depends on INET + default SCST_ISCSI + ---help--- + Adds support for sending a notification upon completion of a + zero-copy TCP/IP transfer. This can speed up certain TCP/IP + software. Currently this is only used by the iSCSI target driver + iSCSI-SCST. + + If unsure, say N. + if INET source "net/ipv4/Kconfig" source "net/ipv6/Kconfig" diff --git a/net/ceph/pagevec.c b/net/ceph/pagevec.c index 5550130..993f710 100644 --- a/net/ceph/pagevec.c +++ b/net/ceph/pagevec.c @@ -51,7 +51,7 @@ void ceph_put_page_vector(struct page **pages, int num_pages, bool dirty) for (i = 0; i < num_pages; i++) { if (dirty) set_page_dirty_lock(pages[i]); - put_page(pages[i]); + net_put_page(pages[i]); } if (is_vmalloc_addr(pages)) vfree(pages); diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 62c67be..35074d3 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -479,7 +479,7 @@ static struct sk_buff *__alloc_rx_skb(unsigned int length, gfp_t gfp_mask, if (likely(data)) { skb = build_skb(data, fragsz); if (unlikely(!skb)) - put_page(virt_to_head_page(data)); + net_put_page(virt_to_head_page(data)); } } else { skb = __alloc_skb(length, gfp_mask, @@ -592,7 +592,7 @@ static void skb_clone_fraglist(struct sk_buff *skb) static void skb_free_head(struct sk_buff *skb) { if (skb->head_frag) - put_page(virt_to_head_page(skb->head)); + net_put_page(virt_to_head_page(skb->head)); else kfree(skb->head); } @@ -920,7 +920,7 @@ int skb_copy_ubufs(struct sk_buff *skb, gfp_t gfp_mask) if (!page) { while (head) { struct page *next = (struct page *)page_private(head); - put_page(head); + net_put_page(head); head = next; } return -ENOMEM; @@ -1767,7 +1767,7 @@ EXPORT_SYMBOL(skb_copy_bits); */ static void sock_spd_release(struct splice_pipe_desc *spd, unsigned int i) { - put_page(spd->pages[i]); + net_put_page(spd->pages[i]); } static struct page *linear_to_page(struct page *page, unsigned int *len, @@ -1820,7 +1820,7 @@ static bool spd_fill_page(struct splice_pipe_desc *spd, spd->partial[spd->nr_pages - 1].len += *len; return false; } - get_page(page); + net_get_page(page); spd->pages[spd->nr_pages] = page; spd->partial[spd->nr_pages].len = *len; spd->partial[spd->nr_pages].offset = offset; @@ -2279,7 +2279,7 @@ skb_zerocopy(struct sk_buff *to, struct sk_buff *from, int len, int hlen) page = virt_to_head_page(from->head); offset = from->data - (unsigned char *)page_address(page); __skb_fill_page_desc(to, 0, page, offset, plen); - get_page(page); + net_get_page(page); j = 1; len -= plen; } @@ -2933,7 +2933,7 @@ int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb, copy); frg_cnt++; pfrag->offset += copy; - get_page(pfrag->page); + net_get_page(pfrag->page); skb->truesize += copy; atomic_add(copy, &sk->sk_wmem_alloc); diff --git a/net/core/sock.c b/net/core/sock.c index 1c7a33d..ec95185 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1864,7 +1864,7 @@ bool skb_page_frag_refill(unsigned int sz, struct page_frag *pfrag, gfp_t gfp) } if (pfrag->offset + sz <= pfrag->size) return true; - put_page(pfrag->page); + net_put_page(pfrag->page); } pfrag->offset = 0; @@ -2615,7 +2615,7 @@ void sk_common_release(struct sock *sk) sk_refcnt_debug_release(sk); if (sk->sk_frag.page) { - put_page(sk->sk_frag.page); + net_put_page(sk->sk_frag.page); sk->sk_frag.page = NULL; } diff --git a/net/ipv4/Makefile b/net/ipv4/Makefile index 518c04e..4072a87 100644 --- a/net/ipv4/Makefile +++ b/net/ipv4/Makefile @@ -57,6 +57,7 @@ obj-$(CONFIG_TCP_CONG_ILLINOIS) += tcp_illinois.o obj-$(CONFIG_MEMCG_KMEM) += tcp_memcontrol.o obj-$(CONFIG_NETLABEL) += cipso_ipv4.o obj-$(CONFIG_GENEVE) += geneve.o +obj-$(CONFIG_TCP_ZERO_COPY_TRANSFER_COMPLETION_NOTIFICATION) += tcp_zero_copy.o obj-$(CONFIG_XFRM) += xfrm4_policy.o xfrm4_state.o xfrm4_input.o \ xfrm4_output.o xfrm4_protocol.o diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index 2e2f687..87f5bff 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -1052,7 +1052,7 @@ alloc_new_skb: __skb_fill_page_desc(skb, i, pfrag->page, pfrag->offset, 0); skb_shinfo(skb)->nr_frags = ++i; - get_page(pfrag->page); + net_get_page(pfrag->page); } copy = min_t(int, copy, pfrag->size - pfrag->offset); if (getfrag(from, @@ -1277,7 +1277,7 @@ ssize_t ip_append_page(struct sock *sk, struct flowi4 *fl4, struct page *page, if (skb_can_coalesce(skb, i, page, offset)) { skb_frag_size_add(&skb_shinfo(skb)->frags[i-1], len); } else if (i < MAX_SKB_FRAGS) { - get_page(page); + net_get_page(page); skb_fill_page_desc(skb, i, page, offset, len); } else { err = -EMSGSIZE; diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 3075723..396b887 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -931,7 +931,7 @@ new_segment: if (can_coalesce) { skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy); } else { - get_page(page); + net_get_page(page); skb_fill_page_desc(skb, i, page, offset, copy); } skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; @@ -1232,7 +1232,7 @@ new_segment: } else { skb_fill_page_desc(skb, i, pfrag->page, pfrag->offset, copy); - get_page(pfrag->page); + net_get_page(pfrag->page); } pfrag->offset += copy; } diff --git a/net/ipv4/tcp_zero_copy.c b/net/ipv4/tcp_zero_copy.c new file mode 100644 index 0000000..430147e --- /dev/null +++ b/net/ipv4/tcp_zero_copy.c @@ -0,0 +1,50 @@ +/* + * Support routines for TCP zero copy transmit + * + * Created by Vladislav Bolkhovitin + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * version 2 as published by the Free Software Foundation. + */ + +#include +#include + +net_get_page_callback_t net_get_page_callback __read_mostly; +EXPORT_SYMBOL_GPL(net_get_page_callback); + +net_put_page_callback_t net_put_page_callback __read_mostly; +EXPORT_SYMBOL_GPL(net_put_page_callback); + +/* + * Caller of this function must ensure that at the moment when it's called + * there are no pages in the system with net_priv field set to non-zero + * value. Hence, this function, as well as net_get_page() and net_put_page(), + * don't need any protection. + */ +int net_set_get_put_page_callbacks( + net_get_page_callback_t get_callback, + net_put_page_callback_t put_callback) +{ + int res = 0; + + if ((net_get_page_callback != NULL) && (get_callback != NULL) && + (net_get_page_callback != get_callback)) { + res = -EBUSY; + goto out; + } + + if ((net_put_page_callback != NULL) && (put_callback != NULL) && + (net_put_page_callback != put_callback)) { + res = -EBUSY; + goto out; + } + + net_get_page_callback = get_callback; + net_put_page_callback = put_callback; + +out: + return res; +} +EXPORT_SYMBOL_GPL(net_set_get_put_page_callbacks); diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 3f5aa99..777f267 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1460,7 +1460,7 @@ alloc_new_skb: __skb_fill_page_desc(skb, i, pfrag->page, pfrag->offset, 0); skb_shinfo(skb)->nr_frags = ++i; - get_page(pfrag->page); + net_get_page(pfrag->page); } copy = min_t(int, copy, pfrag->size - pfrag->offset); if (getfrag(from, -- 1.9.1