--- /dev/null
+/*
+ * 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 = libcfs_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 != 0) {
+ CERROR("Error %d getting sock peer IP\n", rc);
+ return rc;
+ }
+
+ rc = libcfs_sock_getaddr(conn->ksnc_sock, 0,
+ &conn->ksnc_myipaddr, NULL);
+ if (rc != 0) {
+ 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) != 0 && (caps & NETIF_F_ALL_CSUM) != 0);
+}
+
+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 == 0) /* 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 != NULL);
+
+ /* NB we can't trust socket ops to either consume our iovs
+ * or leave them alone. */
+ if (tx->tx_msg.ksm_zc_cookies[0] != 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 != NULL) {
+ rc = sk->sk_prot->sendpage(sk, page,
+ offset, fragsize, msgflg);
+ } else {
+ rc = cfs_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 != 0) {
+ /* 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 == NULL)
+ 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 == NULL)
+ 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 != 0 && i > 0) ||
+ (kiov[i].kiov_offset + kiov[i].kiov_len != PAGE_CACHE_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 == NULL)
+ 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 != NULL) {
+ 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 != 0) {
+ 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 != NULL) {
+ 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 != NULL);
+ 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 != NULL) {
+ 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 != 0) {
+ LASSERT(conn->ksnc_closing);
+ *txmem = *rxmem = *nagle = 0;
+ return -ESHUTDOWN;
+ }
+
+ rc = libcfs_sock_getbuf(sock, txmem, rxmem);
+ if (rc == 0) {
+ len = sizeof(*nagle);
+ rc = kernel_getsockopt(sock, SOL_TCP, TCP_NODELAY,
+ (char *)nagle, &len);
+ }
+
+ ksocknal_connsock_decref(conn);
+
+ if (rc == 0)
+ *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 != 0) {
+ 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 != 0) {
+ 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 != 0) {
+ CERROR("Can't disable nagle: %d\n", rc);
+ return rc;
+ }
+ }
+
+ rc = libcfs_sock_setbuf(sock,
+ *ksocknal_tunables.ksnd_tx_buffer_size,
+ *ksocknal_tunables.ksnd_rx_buffer_size);
+ if (rc != 0) {
+ 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 != 0) {
+ 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 != 0) {
+ 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 != 0) {
+ 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 != 0) {
+ 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 != 0) /* 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 == 0);
+
+ lock_sock(sk);
+ tp->nonagle = nonagle;
+ release_sock(sk);
+
+ ksocknal_connsock_decref(conn);
+}
+
+extern void ksocknal_read_callback(ksock_conn_t *conn);
+extern void ksocknal_write_callback(ksock_conn_t *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 == NULL) { /* 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 = SOCKNAL_WSPACE(sk);
+ min_wpace = SOCKNAL_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 == NULL) ? "" : (conn->ksnc_tx_ready ?
+ " ready" : " blocked"),
+ (conn == NULL) ? "" : (conn->ksnc_tx_scheduled ?
+ " scheduled" : " idle"),
+ (conn == NULL) ? "" : (list_empty(&conn->ksnc_tx_queue) ?
+ " empty" : " queued"));
+
+ if (conn == NULL) { /* 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;
+}
Code Review / kvmfornfv.git / blobdiff