| /* |
| * GPL HEADER START |
| * |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 only, |
| * as published by the Free Software Foundation. |
| * |
| * This program is distributed in the hope that it will be useful, but |
| * WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * General Public License version 2 for more details (a copy is included |
| * in the LICENSE file that accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License |
| * version 2 along with this program; If not, see |
| * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf |
| * |
| * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| * CA 95054 USA or visit www.sun.com if you need additional information or |
| * have any questions. |
| * |
| * GPL HEADER END |
| */ |
| /* |
| * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved. |
| * Use is subject to license terms. |
| * |
| * Copyright (c) 2011, 2012, Intel Corporation. |
| */ |
| /* |
| * This file is part of Lustre, http://www.lustre.org/ |
| * Lustre is a trademark of Sun Microsystems, Inc. |
| */ |
| |
| #include "socklnd.h" |
| |
| int |
| ksocknal_lib_get_conn_addrs(ksock_conn_t *conn) |
| { |
| int rc = lnet_sock_getaddr(conn->ksnc_sock, 1, &conn->ksnc_ipaddr, |
| &conn->ksnc_port); |
| |
| /* Didn't need the {get,put}connsock dance to deref ksnc_sock... */ |
| LASSERT(!conn->ksnc_closing); |
| |
| if (rc) { |
| CERROR("Error %d getting sock peer IP\n", rc); |
| return rc; |
| } |
| |
| rc = lnet_sock_getaddr(conn->ksnc_sock, 0, &conn->ksnc_myipaddr, NULL); |
| if (rc) { |
| CERROR("Error %d getting sock local IP\n", rc); |
| return rc; |
| } |
| |
| return 0; |
| } |
| |
| int |
| ksocknal_lib_zc_capable(ksock_conn_t *conn) |
| { |
| int caps = conn->ksnc_sock->sk->sk_route_caps; |
| |
| if (conn->ksnc_proto == &ksocknal_protocol_v1x) |
| return 0; |
| |
| /* |
| * ZC if the socket supports scatter/gather and doesn't need software |
| * checksums |
| */ |
| return ((caps & NETIF_F_SG) && (caps & NETIF_F_CSUM_MASK)); |
| } |
| |
| int |
| ksocknal_lib_send_iov(ksock_conn_t *conn, ksock_tx_t *tx) |
| { |
| struct socket *sock = conn->ksnc_sock; |
| int nob; |
| int rc; |
| |
| if (*ksocknal_tunables.ksnd_enable_csum && /* checksum enabled */ |
| conn->ksnc_proto == &ksocknal_protocol_v2x && /* V2.x connection */ |
| tx->tx_nob == tx->tx_resid && /* frist sending */ |
| !tx->tx_msg.ksm_csum) /* not checksummed */ |
| ksocknal_lib_csum_tx(tx); |
| |
| /* |
| * NB we can't trust socket ops to either consume our iovs |
| * or leave them alone. |
| */ |
| { |
| #if SOCKNAL_SINGLE_FRAG_TX |
| struct kvec scratch; |
| struct kvec *scratchiov = &scratch; |
| unsigned int niov = 1; |
| #else |
| struct kvec *scratchiov = conn->ksnc_scheduler->kss_scratch_iov; |
| unsigned int niov = tx->tx_niov; |
| #endif |
| struct msghdr msg = {.msg_flags = MSG_DONTWAIT}; |
| int i; |
| |
| for (nob = i = 0; i < niov; i++) { |
| scratchiov[i] = tx->tx_iov[i]; |
| nob += scratchiov[i].iov_len; |
| } |
| |
| if (!list_empty(&conn->ksnc_tx_queue) || |
| nob < tx->tx_resid) |
| msg.msg_flags |= MSG_MORE; |
| |
| rc = kernel_sendmsg(sock, &msg, scratchiov, niov, nob); |
| } |
| return rc; |
| } |
| |
| int |
| ksocknal_lib_send_kiov(ksock_conn_t *conn, ksock_tx_t *tx) |
| { |
| struct socket *sock = conn->ksnc_sock; |
| lnet_kiov_t *kiov = tx->tx_kiov; |
| int rc; |
| int nob; |
| |
| /* Not NOOP message */ |
| LASSERT(tx->tx_lnetmsg); |
| |
| /* |
| * NB we can't trust socket ops to either consume our iovs |
| * or leave them alone. |
| */ |
| if (tx->tx_msg.ksm_zc_cookies[0]) { |
| /* Zero copy is enabled */ |
| struct sock *sk = sock->sk; |
| struct page *page = kiov->kiov_page; |
| int offset = kiov->kiov_offset; |
| int fragsize = kiov->kiov_len; |
| int msgflg = MSG_DONTWAIT; |
| |
| CDEBUG(D_NET, "page %p + offset %x for %d\n", |
| page, offset, kiov->kiov_len); |
| |
| if (!list_empty(&conn->ksnc_tx_queue) || |
| fragsize < tx->tx_resid) |
| msgflg |= MSG_MORE; |
| |
| if (sk->sk_prot->sendpage) { |
| rc = sk->sk_prot->sendpage(sk, page, |
| offset, fragsize, msgflg); |
| } else { |
| rc = tcp_sendpage(sk, page, offset, fragsize, msgflg); |
| } |
| } else { |
| #if SOCKNAL_SINGLE_FRAG_TX || !SOCKNAL_RISK_KMAP_DEADLOCK |
| struct kvec scratch; |
| struct kvec *scratchiov = &scratch; |
| unsigned int niov = 1; |
| #else |
| #ifdef CONFIG_HIGHMEM |
| #warning "XXX risk of kmap deadlock on multiple frags..." |
| #endif |
| struct kvec *scratchiov = conn->ksnc_scheduler->kss_scratch_iov; |
| unsigned int niov = tx->tx_nkiov; |
| #endif |
| struct msghdr msg = {.msg_flags = MSG_DONTWAIT}; |
| int i; |
| |
| for (nob = i = 0; i < niov; i++) { |
| scratchiov[i].iov_base = kmap(kiov[i].kiov_page) + |
| kiov[i].kiov_offset; |
| nob += scratchiov[i].iov_len = kiov[i].kiov_len; |
| } |
| |
| if (!list_empty(&conn->ksnc_tx_queue) || |
| nob < tx->tx_resid) |
| msg.msg_flags |= MSG_MORE; |
| |
| rc = kernel_sendmsg(sock, &msg, (struct kvec *)scratchiov, niov, nob); |
| |
| for (i = 0; i < niov; i++) |
| kunmap(kiov[i].kiov_page); |
| } |
| return rc; |
| } |
| |
| void |
| ksocknal_lib_eager_ack(ksock_conn_t *conn) |
| { |
| int opt = 1; |
| struct socket *sock = conn->ksnc_sock; |
| |
| /* |
| * Remind the socket to ACK eagerly. If I don't, the socket might |
| * think I'm about to send something it could piggy-back the ACK |
| * on, introducing delay in completing zero-copy sends in my |
| * peer. |
| */ |
| kernel_setsockopt(sock, SOL_TCP, TCP_QUICKACK, (char *)&opt, |
| sizeof(opt)); |
| } |
| |
| int |
| ksocknal_lib_recv_iov(ksock_conn_t *conn) |
| { |
| #if SOCKNAL_SINGLE_FRAG_RX |
| struct kvec scratch; |
| struct kvec *scratchiov = &scratch; |
| unsigned int niov = 1; |
| #else |
| struct kvec *scratchiov = conn->ksnc_scheduler->kss_scratch_iov; |
| unsigned int niov = conn->ksnc_rx_niov; |
| #endif |
| struct kvec *iov = conn->ksnc_rx_iov; |
| struct msghdr msg = { |
| .msg_flags = 0 |
| }; |
| int nob; |
| int i; |
| int rc; |
| int fragnob; |
| int sum; |
| __u32 saved_csum; |
| |
| /* |
| * NB we can't trust socket ops to either consume our iovs |
| * or leave them alone. |
| */ |
| LASSERT(niov > 0); |
| |
| for (nob = i = 0; i < niov; i++) { |
| scratchiov[i] = iov[i]; |
| nob += scratchiov[i].iov_len; |
| } |
| LASSERT(nob <= conn->ksnc_rx_nob_wanted); |
| |
| rc = kernel_recvmsg(conn->ksnc_sock, &msg, scratchiov, niov, nob, |
| MSG_DONTWAIT); |
| |
| saved_csum = 0; |
| if (conn->ksnc_proto == &ksocknal_protocol_v2x) { |
| saved_csum = conn->ksnc_msg.ksm_csum; |
| conn->ksnc_msg.ksm_csum = 0; |
| } |
| |
| if (saved_csum) { |
| /* accumulate checksum */ |
| for (i = 0, sum = rc; sum > 0; i++, sum -= fragnob) { |
| LASSERT(i < niov); |
| |
| fragnob = iov[i].iov_len; |
| if (fragnob > sum) |
| fragnob = sum; |
| |
| conn->ksnc_rx_csum = ksocknal_csum(conn->ksnc_rx_csum, |
| iov[i].iov_base, fragnob); |
| } |
| conn->ksnc_msg.ksm_csum = saved_csum; |
| } |
| |
| return rc; |
| } |
| |
| static void |
| ksocknal_lib_kiov_vunmap(void *addr) |
| { |
| if (!addr) |
| return; |
| |
| vunmap(addr); |
| } |
| |
| static void * |
| ksocknal_lib_kiov_vmap(lnet_kiov_t *kiov, int niov, |
| struct kvec *iov, struct page **pages) |
| { |
| void *addr; |
| int nob; |
| int i; |
| |
| if (!*ksocknal_tunables.ksnd_zc_recv || !pages) |
| return NULL; |
| |
| LASSERT(niov <= LNET_MAX_IOV); |
| |
| if (niov < 2 || |
| niov < *ksocknal_tunables.ksnd_zc_recv_min_nfrags) |
| return NULL; |
| |
| for (nob = i = 0; i < niov; i++) { |
| if ((kiov[i].kiov_offset && i > 0) || |
| (kiov[i].kiov_offset + kiov[i].kiov_len != PAGE_SIZE && i < niov - 1)) |
| return NULL; |
| |
| pages[i] = kiov[i].kiov_page; |
| nob += kiov[i].kiov_len; |
| } |
| |
| addr = vmap(pages, niov, VM_MAP, PAGE_KERNEL); |
| if (!addr) |
| return NULL; |
| |
| iov->iov_base = addr + kiov[0].kiov_offset; |
| iov->iov_len = nob; |
| |
| return addr; |
| } |
| |
| int |
| ksocknal_lib_recv_kiov(ksock_conn_t *conn) |
| { |
| #if SOCKNAL_SINGLE_FRAG_RX || !SOCKNAL_RISK_KMAP_DEADLOCK |
| struct kvec scratch; |
| struct kvec *scratchiov = &scratch; |
| struct page **pages = NULL; |
| unsigned int niov = 1; |
| #else |
| #ifdef CONFIG_HIGHMEM |
| #warning "XXX risk of kmap deadlock on multiple frags..." |
| #endif |
| struct kvec *scratchiov = conn->ksnc_scheduler->kss_scratch_iov; |
| struct page **pages = conn->ksnc_scheduler->kss_rx_scratch_pgs; |
| unsigned int niov = conn->ksnc_rx_nkiov; |
| #endif |
| lnet_kiov_t *kiov = conn->ksnc_rx_kiov; |
| struct msghdr msg = { |
| .msg_flags = 0 |
| }; |
| int nob; |
| int i; |
| int rc; |
| void *base; |
| void *addr; |
| int sum; |
| int fragnob; |
| int n; |
| |
| /* |
| * NB we can't trust socket ops to either consume our iovs |
| * or leave them alone. |
| */ |
| addr = ksocknal_lib_kiov_vmap(kiov, niov, scratchiov, pages); |
| if (addr) { |
| nob = scratchiov[0].iov_len; |
| n = 1; |
| |
| } else { |
| for (nob = i = 0; i < niov; i++) { |
| nob += scratchiov[i].iov_len = kiov[i].kiov_len; |
| scratchiov[i].iov_base = kmap(kiov[i].kiov_page) + |
| kiov[i].kiov_offset; |
| } |
| n = niov; |
| } |
| |
| LASSERT(nob <= conn->ksnc_rx_nob_wanted); |
| |
| rc = kernel_recvmsg(conn->ksnc_sock, &msg, (struct kvec *)scratchiov, |
| n, nob, MSG_DONTWAIT); |
| |
| if (conn->ksnc_msg.ksm_csum) { |
| for (i = 0, sum = rc; sum > 0; i++, sum -= fragnob) { |
| LASSERT(i < niov); |
| |
| /* |
| * Dang! have to kmap again because I have nowhere to |
| * stash the mapped address. But by doing it while the |
| * page is still mapped, the kernel just bumps the map |
| * count and returns me the address it stashed. |
| */ |
| base = kmap(kiov[i].kiov_page) + kiov[i].kiov_offset; |
| fragnob = kiov[i].kiov_len; |
| if (fragnob > sum) |
| fragnob = sum; |
| |
| conn->ksnc_rx_csum = ksocknal_csum(conn->ksnc_rx_csum, |
| base, fragnob); |
| |
| kunmap(kiov[i].kiov_page); |
| } |
| } |
| |
| if (addr) { |
| ksocknal_lib_kiov_vunmap(addr); |
| } else { |
| for (i = 0; i < niov; i++) |
| kunmap(kiov[i].kiov_page); |
| } |
| |
| return rc; |
| } |
| |
| void |
| ksocknal_lib_csum_tx(ksock_tx_t *tx) |
| { |
| int i; |
| __u32 csum; |
| void *base; |
| |
| LASSERT(tx->tx_iov[0].iov_base == &tx->tx_msg); |
| LASSERT(tx->tx_conn); |
| LASSERT(tx->tx_conn->ksnc_proto == &ksocknal_protocol_v2x); |
| |
| tx->tx_msg.ksm_csum = 0; |
| |
| csum = ksocknal_csum(~0, tx->tx_iov[0].iov_base, |
| tx->tx_iov[0].iov_len); |
| |
| if (tx->tx_kiov) { |
| for (i = 0; i < tx->tx_nkiov; i++) { |
| base = kmap(tx->tx_kiov[i].kiov_page) + |
| tx->tx_kiov[i].kiov_offset; |
| |
| csum = ksocknal_csum(csum, base, tx->tx_kiov[i].kiov_len); |
| |
| kunmap(tx->tx_kiov[i].kiov_page); |
| } |
| } else { |
| for (i = 1; i < tx->tx_niov; i++) |
| csum = ksocknal_csum(csum, tx->tx_iov[i].iov_base, |
| tx->tx_iov[i].iov_len); |
| } |
| |
| if (*ksocknal_tunables.ksnd_inject_csum_error) { |
| csum++; |
| *ksocknal_tunables.ksnd_inject_csum_error = 0; |
| } |
| |
| tx->tx_msg.ksm_csum = csum; |
| } |
| |
| int |
| ksocknal_lib_get_conn_tunables(ksock_conn_t *conn, int *txmem, int *rxmem, int *nagle) |
| { |
| struct socket *sock = conn->ksnc_sock; |
| int len; |
| int rc; |
| |
| rc = ksocknal_connsock_addref(conn); |
| if (rc) { |
| LASSERT(conn->ksnc_closing); |
| *txmem = *rxmem = *nagle = 0; |
| return -ESHUTDOWN; |
| } |
| |
| rc = lnet_sock_getbuf(sock, txmem, rxmem); |
| if (!rc) { |
| len = sizeof(*nagle); |
| rc = kernel_getsockopt(sock, SOL_TCP, TCP_NODELAY, |
| (char *)nagle, &len); |
| } |
| |
| ksocknal_connsock_decref(conn); |
| |
| if (!rc) |
| *nagle = !*nagle; |
| else |
| *txmem = *rxmem = *nagle = 0; |
| |
| return rc; |
| } |
| |
| int |
| ksocknal_lib_setup_sock(struct socket *sock) |
| { |
| int rc; |
| int option; |
| int keep_idle; |
| int keep_intvl; |
| int keep_count; |
| int do_keepalive; |
| struct linger linger; |
| |
| sock->sk->sk_allocation = GFP_NOFS; |
| |
| /* |
| * Ensure this socket aborts active sends immediately when we close |
| * it. |
| */ |
| linger.l_onoff = 0; |
| linger.l_linger = 0; |
| |
| rc = kernel_setsockopt(sock, SOL_SOCKET, SO_LINGER, (char *)&linger, |
| sizeof(linger)); |
| if (rc) { |
| CERROR("Can't set SO_LINGER: %d\n", rc); |
| return rc; |
| } |
| |
| option = -1; |
| rc = kernel_setsockopt(sock, SOL_TCP, TCP_LINGER2, (char *)&option, |
| sizeof(option)); |
| if (rc) { |
| CERROR("Can't set SO_LINGER2: %d\n", rc); |
| return rc; |
| } |
| |
| if (!*ksocknal_tunables.ksnd_nagle) { |
| option = 1; |
| |
| rc = kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY, |
| (char *)&option, sizeof(option)); |
| if (rc) { |
| CERROR("Can't disable nagle: %d\n", rc); |
| return rc; |
| } |
| } |
| |
| rc = lnet_sock_setbuf(sock, *ksocknal_tunables.ksnd_tx_buffer_size, |
| *ksocknal_tunables.ksnd_rx_buffer_size); |
| if (rc) { |
| CERROR("Can't set buffer tx %d, rx %d buffers: %d\n", |
| *ksocknal_tunables.ksnd_tx_buffer_size, |
| *ksocknal_tunables.ksnd_rx_buffer_size, rc); |
| return rc; |
| } |
| |
| /* TCP_BACKOFF_* sockopt tunables unsupported in stock kernels */ |
| |
| /* snapshot tunables */ |
| keep_idle = *ksocknal_tunables.ksnd_keepalive_idle; |
| keep_count = *ksocknal_tunables.ksnd_keepalive_count; |
| keep_intvl = *ksocknal_tunables.ksnd_keepalive_intvl; |
| |
| do_keepalive = (keep_idle > 0 && keep_count > 0 && keep_intvl > 0); |
| |
| option = (do_keepalive ? 1 : 0); |
| rc = kernel_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (char *)&option, |
| sizeof(option)); |
| if (rc) { |
| CERROR("Can't set SO_KEEPALIVE: %d\n", rc); |
| return rc; |
| } |
| |
| if (!do_keepalive) |
| return 0; |
| |
| rc = kernel_setsockopt(sock, SOL_TCP, TCP_KEEPIDLE, (char *)&keep_idle, |
| sizeof(keep_idle)); |
| if (rc) { |
| CERROR("Can't set TCP_KEEPIDLE: %d\n", rc); |
| return rc; |
| } |
| |
| rc = kernel_setsockopt(sock, SOL_TCP, TCP_KEEPINTVL, |
| (char *)&keep_intvl, sizeof(keep_intvl)); |
| if (rc) { |
| CERROR("Can't set TCP_KEEPINTVL: %d\n", rc); |
| return rc; |
| } |
| |
| rc = kernel_setsockopt(sock, SOL_TCP, TCP_KEEPCNT, (char *)&keep_count, |
| sizeof(keep_count)); |
| if (rc) { |
| CERROR("Can't set TCP_KEEPCNT: %d\n", rc); |
| return rc; |
| } |
| |
| return 0; |
| } |
| |
| void |
| ksocknal_lib_push_conn(ksock_conn_t *conn) |
| { |
| struct sock *sk; |
| struct tcp_sock *tp; |
| int nonagle; |
| int val = 1; |
| int rc; |
| |
| rc = ksocknal_connsock_addref(conn); |
| if (rc) /* being shut down */ |
| return; |
| |
| sk = conn->ksnc_sock->sk; |
| tp = tcp_sk(sk); |
| |
| lock_sock(sk); |
| nonagle = tp->nonagle; |
| tp->nonagle = 1; |
| release_sock(sk); |
| |
| rc = kernel_setsockopt(conn->ksnc_sock, SOL_TCP, TCP_NODELAY, |
| (char *)&val, sizeof(val)); |
| LASSERT(!rc); |
| |
| lock_sock(sk); |
| tp->nonagle = nonagle; |
| release_sock(sk); |
| |
| ksocknal_connsock_decref(conn); |
| } |
| |
| /* |
| * socket call back in Linux |
| */ |
| static void |
| ksocknal_data_ready(struct sock *sk) |
| { |
| ksock_conn_t *conn; |
| |
| /* interleave correctly with closing sockets... */ |
| LASSERT(!in_irq()); |
| read_lock(&ksocknal_data.ksnd_global_lock); |
| |
| conn = sk->sk_user_data; |
| if (!conn) { /* raced with ksocknal_terminate_conn */ |
| LASSERT(sk->sk_data_ready != &ksocknal_data_ready); |
| sk->sk_data_ready(sk); |
| } else { |
| ksocknal_read_callback(conn); |
| } |
| |
| read_unlock(&ksocknal_data.ksnd_global_lock); |
| } |
| |
| static void |
| ksocknal_write_space(struct sock *sk) |
| { |
| ksock_conn_t *conn; |
| int wspace; |
| int min_wpace; |
| |
| /* interleave correctly with closing sockets... */ |
| LASSERT(!in_irq()); |
| read_lock(&ksocknal_data.ksnd_global_lock); |
| |
| conn = sk->sk_user_data; |
| wspace = sk_stream_wspace(sk); |
| min_wpace = sk_stream_min_wspace(sk); |
| |
| CDEBUG(D_NET, "sk %p wspace %d low water %d conn %p%s%s%s\n", |
| sk, wspace, min_wpace, conn, |
| !conn ? "" : (conn->ksnc_tx_ready ? |
| " ready" : " blocked"), |
| !conn ? "" : (conn->ksnc_tx_scheduled ? |
| " scheduled" : " idle"), |
| !conn ? "" : (list_empty(&conn->ksnc_tx_queue) ? |
| " empty" : " queued")); |
| |
| if (!conn) { /* raced with ksocknal_terminate_conn */ |
| LASSERT(sk->sk_write_space != &ksocknal_write_space); |
| sk->sk_write_space(sk); |
| |
| read_unlock(&ksocknal_data.ksnd_global_lock); |
| return; |
| } |
| |
| if (wspace >= min_wpace) { /* got enough space */ |
| ksocknal_write_callback(conn); |
| |
| /* |
| * Clear SOCK_NOSPACE _after_ ksocknal_write_callback so the |
| * ENOMEM check in ksocknal_transmit is race-free (think about |
| * it). |
| */ |
| clear_bit(SOCK_NOSPACE, &sk->sk_socket->flags); |
| } |
| |
| read_unlock(&ksocknal_data.ksnd_global_lock); |
| } |
| |
| void |
| ksocknal_lib_save_callback(struct socket *sock, ksock_conn_t *conn) |
| { |
| conn->ksnc_saved_data_ready = sock->sk->sk_data_ready; |
| conn->ksnc_saved_write_space = sock->sk->sk_write_space; |
| } |
| |
| void |
| ksocknal_lib_set_callback(struct socket *sock, ksock_conn_t *conn) |
| { |
| sock->sk->sk_user_data = conn; |
| sock->sk->sk_data_ready = ksocknal_data_ready; |
| sock->sk->sk_write_space = ksocknal_write_space; |
| return; |
| } |
| |
| void |
| ksocknal_lib_reset_callback(struct socket *sock, ksock_conn_t *conn) |
| { |
| /* |
| * Remove conn's network callbacks. |
| * NB I _have_ to restore the callback, rather than storing a noop, |
| * since the socket could survive past this module being unloaded!! |
| */ |
| sock->sk->sk_data_ready = conn->ksnc_saved_data_ready; |
| sock->sk->sk_write_space = conn->ksnc_saved_write_space; |
| |
| /* |
| * A callback could be in progress already; they hold a read lock |
| * on ksnd_global_lock (to serialise with me) and NOOP if |
| * sk_user_data is NULL. |
| */ |
| sock->sk->sk_user_data = NULL; |
| |
| return ; |
| } |
| |
| int |
| ksocknal_lib_memory_pressure(ksock_conn_t *conn) |
| { |
| int rc = 0; |
| ksock_sched_t *sched; |
| |
| sched = conn->ksnc_scheduler; |
| spin_lock_bh(&sched->kss_lock); |
| |
| if (!test_bit(SOCK_NOSPACE, &conn->ksnc_sock->flags) && |
| !conn->ksnc_tx_ready) { |
| /* |
| * SOCK_NOSPACE is set when the socket fills |
| * and cleared in the write_space callback |
| * (which also sets ksnc_tx_ready). If |
| * SOCK_NOSPACE and ksnc_tx_ready are BOTH |
| * zero, I didn't fill the socket and |
| * write_space won't reschedule me, so I |
| * return -ENOMEM to get my caller to retry |
| * after a timeout |
| */ |
| rc = -ENOMEM; |
| } |
| |
| spin_unlock_bh(&sched->kss_lock); |
| |
| return rc; |
| } |