=== modified file 'include/linux/mm_types.h' --- old/include/linux/mm_types.h 2012-01-10 22:58:17 +0000 +++ new/include/linux/mm_types.h 2012-01-10 23:02:48 +0000 @@ -149,6 +149,17 @@ struct page { */ void *shadow; #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 } /* * If another subsystem starts using the double word pairing for atomic === modified file 'include/linux/net.h' --- old/include/linux/net.h 2012-01-10 22:58:17 +0000 +++ new/include/linux/net.h 2012-01-10 23:02:48 +0000 @@ -61,6 +61,7 @@ typedef enum { #include /* For O_CLOEXEC and O_NONBLOCK */ #include #include +#include struct poll_table_struct; struct pipe_inode_info; @@ -289,5 +290,44 @@ extern int kernel_sock_shutdown(struct s MODULE_ALIAS("net-pf-" __stringify(pf) "-proto-" __stringify(proto) \ "-type-" __stringify(type)) +#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 */ + #endif /* __KERNEL__ */ #endif /* _LINUX_NET_H */ === modified file 'include/linux/skbuff.h' --- old/include/linux/skbuff.h 2012-01-10 22:58:17 +0000 +++ new/include/linux/skbuff.h 2012-01-10 23:15:31 +0000 @@ -1712,7 +1712,7 @@ static inline struct page *skb_frag_page */ static inline void __skb_frag_ref(skb_frag_t *frag) { - get_page(skb_frag_page(frag)); + net_get_page(skb_frag_page(frag)); } /** @@ -1735,7 +1735,7 @@ static inline void skb_frag_ref(struct s */ static inline void __skb_frag_unref(skb_frag_t *frag) { - put_page(skb_frag_page(frag)); + net_put_page(skb_frag_page(frag)); } /** === modified file 'net/Kconfig' --- old/net/Kconfig 2012-01-10 22:58:17 +0000 +++ new/net/Kconfig 2012-01-10 23:02:48 +0000 @@ -72,6 +72,18 @@ 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" === modified file 'net/core/skbuff.c' --- old/net/core/skbuff.c 2012-01-10 22:58:17 +0000 +++ new/net/core/skbuff.c 2012-01-10 23:02:48 +0000 @@ -77,13 +77,13 @@ static struct kmem_cache *skbuff_fclone_ static void sock_pipe_buf_release(struct pipe_inode_info *pipe, struct pipe_buffer *buf) { - put_page(buf->page); + net_put_page(buf->page); } static void sock_pipe_buf_get(struct pipe_inode_info *pipe, struct pipe_buffer *buf) { - get_page(buf->page); + net_get_page(buf->page); } static int sock_pipe_buf_steal(struct pipe_inode_info *pipe, @@ -654,7 +654,7 @@ int skb_copy_ubufs(struct sk_buff *skb, if (!page) { while (head) { struct page *next = (struct page *)head->private; - put_page(head); + net_put_page(head); head = next; } return -ENOMEM; @@ -1493,7 +1493,7 @@ 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 inline struct page *linear_to_page(struct page *page, unsigned int *len, @@ -1517,7 +1517,7 @@ new_page: off = sk->sk_sndmsg_off; mlen = PAGE_SIZE - off; if (mlen < 64 && mlen < *len) { - put_page(p); + net_put_page(p); goto new_page; } @@ -1527,7 +1527,7 @@ new_page: memcpy(page_address(p) + off, page_address(page) + *offset, *len); sk->sk_sndmsg_off += *len; *offset = off; - get_page(p); + net_get_page(p); return p; } @@ -1549,7 +1549,7 @@ static inline int spd_fill_page(struct s if (!page) return 1; } else - get_page(page); + net_get_page(page); spd->pages[spd->nr_pages] = page; spd->partial[spd->nr_pages].len = *len; === modified file 'net/ipv4/Makefile' --- old/net/ipv4/Makefile 2012-01-10 22:58:17 +0000 +++ new/net/ipv4/Makefile 2012-01-10 23:02:48 +0000 @@ -48,6 +48,7 @@ obj-$(CONFIG_TCP_CONG_LP) += tcp_lp.o obj-$(CONFIG_TCP_CONG_YEAH) += tcp_yeah.o obj-$(CONFIG_TCP_CONG_ILLINOIS) += tcp_illinois.o obj-$(CONFIG_NETLABEL) += cipso_ipv4.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 === modified file 'net/ipv4/ip_output.c' --- old/net/ipv4/ip_output.c 2012-01-10 22:58:17 +0000 +++ new/net/ipv4/ip_output.c 2012-01-10 23:02:48 +0000 @@ -1232,7 +1232,7 @@ ssize_t ip_append_page(struct sock *sk, 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; === modified file 'net/ipv4/tcp.c' --- old/net/ipv4/tcp.c 2012-01-10 22:58:17 +0000 +++ new/net/ipv4/tcp.c 2012-01-10 23:02:48 +0000 @@ -815,7 +815,7 @@ 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); } @@ -1022,7 +1022,7 @@ new_segment: goto new_segment; } else if (page) { if (off == PAGE_SIZE) { - put_page(page); + net_put_page(page); TCP_PAGE(sk) = page = NULL; off = 0; } @@ -1062,9 +1062,9 @@ new_segment: } else { skb_fill_page_desc(skb, i, page, off, copy); if (TCP_PAGE(sk)) { - get_page(page); + net_get_page(page); } else if (off + copy < PAGE_SIZE) { - get_page(page); + net_get_page(page); TCP_PAGE(sk) = page; } } === added file 'net/ipv4/tcp_zero_copy.c' --- old/net/ipv4/tcp_zero_copy.c 1970-01-01 00:00:00 +0000 +++ new/net/ipv4/tcp_zero_copy.c 2012-01-10 23:43:22 +0000 @@ -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);