Merge branch 'perf/core' into perf/uprobes

Merge in latest upstream (and the latest perf development tree),
to prepare for tooling changes, and also to pick up v3.4 MM
changes that the uprobes code needs to take care of.

Signed-off-by: Ingo Molnar <mingo@kernel.org>

1 files changed, 235 insertions, 221 deletions

diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index ad5b70801f3..f0993af2ae4 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -38,48 +38,54 @@ static char tag_keepalive = CEPH_MSGR_TAG_KEEPALIVE;
 static struct lock_class_key socket_class;
 #endif
 
+/*
+ * When skipping (ignoring) a block of input we read it into a "skip
+ * buffer," which is this many bytes in size.
+ */
+#define SKIP_BUF_SIZE	1024
 
 static void queue_con(struct ceph_connection *con);
 static void con_work(struct work_struct *);
 static void ceph_fault(struct ceph_connection *con);
 
 /*
- * nicely render a sockaddr as a string.
+ * Nicely render a sockaddr as a string.  An array of formatted
+ * strings is used, to approximate reentrancy.
  */
-#define MAX_ADDR_STR 20
-#define MAX_ADDR_STR_LEN 60
-static char addr_str[MAX_ADDR_STR][MAX_ADDR_STR_LEN];
-static DEFINE_SPINLOCK(addr_str_lock);
-static int last_addr_str;
+#define ADDR_STR_COUNT_LOG	5	/* log2(# address strings in array) */
+#define ADDR_STR_COUNT		(1 << ADDR_STR_COUNT_LOG)
+#define ADDR_STR_COUNT_MASK	(ADDR_STR_COUNT - 1)
+#define MAX_ADDR_STR_LEN	64	/* 54 is enough */
+
+static char addr_str[ADDR_STR_COUNT][MAX_ADDR_STR_LEN];
+static atomic_t addr_str_seq = ATOMIC_INIT(0);
+
+static struct page *zero_page;		/* used in certain error cases */
 
 const char *ceph_pr_addr(const struct sockaddr_storage *ss)
 {
 	int i;
 	char *s;
-	struct sockaddr_in *in4 = (void *)ss;
-	struct sockaddr_in6 *in6 = (void *)ss;
-
-	spin_lock(&addr_str_lock);
-	i = last_addr_str++;
-	if (last_addr_str == MAX_ADDR_STR)
-		last_addr_str = 0;
-	spin_unlock(&addr_str_lock);
+	struct sockaddr_in *in4 = (struct sockaddr_in *) ss;
+	struct sockaddr_in6 *in6 = (struct sockaddr_in6 *) ss;
+
+	i = atomic_inc_return(&addr_str_seq) & ADDR_STR_COUNT_MASK;
 	s = addr_str[i];
 
 	switch (ss->ss_family) {
 	case AF_INET:
-		snprintf(s, MAX_ADDR_STR_LEN, "%pI4:%u", &in4->sin_addr,
-			 (unsigned int)ntohs(in4->sin_port));
+		snprintf(s, MAX_ADDR_STR_LEN, "%pI4:%hu", &in4->sin_addr,
+			 ntohs(in4->sin_port));
 		break;
 
 	case AF_INET6:
-		snprintf(s, MAX_ADDR_STR_LEN, "[%pI6c]:%u", &in6->sin6_addr,
-			 (unsigned int)ntohs(in6->sin6_port));
+		snprintf(s, MAX_ADDR_STR_LEN, "[%pI6c]:%hu", &in6->sin6_addr,
+			 ntohs(in6->sin6_port));
 		break;
 
 	default:
-		snprintf(s, MAX_ADDR_STR_LEN, "(unknown sockaddr family %d)",
-			 (int)ss->ss_family);
+		snprintf(s, MAX_ADDR_STR_LEN, "(unknown sockaddr family %hu)",
+			 ss->ss_family);
 	}
 
 	return s;
@@ -95,22 +101,43 @@ static void encode_my_addr(struct ceph_messenger *msgr)
 /*
  * work queue for all reading and writing to/from the socket.
  */
-struct workqueue_struct *ceph_msgr_wq;
+static struct workqueue_struct *ceph_msgr_wq;
+
+void _ceph_msgr_exit(void)
+{
+	if (ceph_msgr_wq) {
+		destroy_workqueue(ceph_msgr_wq);
+		ceph_msgr_wq = NULL;
+	}
+
+	BUG_ON(zero_page == NULL);
+	kunmap(zero_page);
+	page_cache_release(zero_page);
+	zero_page = NULL;
+}
 
 int ceph_msgr_init(void)
 {
+	BUG_ON(zero_page != NULL);
+	zero_page = ZERO_PAGE(0);
+	page_cache_get(zero_page);
+
 	ceph_msgr_wq = alloc_workqueue("ceph-msgr", WQ_NON_REENTRANT, 0);
-	if (!ceph_msgr_wq) {
-		pr_err("msgr_init failed to create workqueue\n");
-		return -ENOMEM;
-	}
-	return 0;
+	if (ceph_msgr_wq)
+		return 0;
+
+	pr_err("msgr_init failed to create workqueue\n");
+	_ceph_msgr_exit();
+
+	return -ENOMEM;
 }
 EXPORT_SYMBOL(ceph_msgr_init);
 
 void ceph_msgr_exit(void)
 {
-	destroy_workqueue(ceph_msgr_wq);
+	BUG_ON(ceph_msgr_wq == NULL);
+
+	_ceph_msgr_exit();
 }
 EXPORT_SYMBOL(ceph_msgr_exit);
 
@@ -128,8 +155,8 @@ EXPORT_SYMBOL(ceph_msgr_flush);
 /* data available on socket, or listen socket received a connect */
 static void ceph_data_ready(struct sock *sk, int count_unused)
 {
-	struct ceph_connection *con =
-		(struct ceph_connection *)sk->sk_user_data;
+	struct ceph_connection *con = sk->sk_user_data;
+
 	if (sk->sk_state != TCP_CLOSE_WAIT) {
 		dout("ceph_data_ready on %p state = %lu, queueing work\n",
 		     con, con->state);
@@ -140,26 +167,30 @@ static void ceph_data_ready(struct sock *sk, int count_unused)
 /* socket has buffer space for writing */
 static void ceph_write_space(struct sock *sk)
 {
-	struct ceph_connection *con =
-		(struct ceph_connection *)sk->sk_user_data;
+	struct ceph_connection *con = sk->sk_user_data;
 
-	/* only queue to workqueue if there is data we want to write. */
+	/* only queue to workqueue if there is data we want to write,
+	 * and there is sufficient space in the socket buffer to accept
+	 * more data.  clear SOCK_NOSPACE so that ceph_write_space()
+	 * doesn't get called again until try_write() fills the socket
+	 * buffer. See net/ipv4/tcp_input.c:tcp_check_space()
+	 * and net/core/stream.c:sk_stream_write_space().
+	 */
 	if (test_bit(WRITE_PENDING, &con->state)) {
-		dout("ceph_write_space %p queueing write work\n", con);
-		queue_con(con);
+		if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
+			dout("ceph_write_space %p queueing write work\n", con);
+			clear_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
+			queue_con(con);
+		}
 	} else {
 		dout("ceph_write_space %p nothing to write\n", con);
 	}
-
-	/* since we have our own write_space, clear the SOCK_NOSPACE flag */
-	clear_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
 }
 
 /* socket's state has changed */
 static void ceph_state_change(struct sock *sk)
 {
-	struct ceph_connection *con =
-		(struct ceph_connection *)sk->sk_user_data;
+	struct ceph_connection *con = sk->sk_user_data;
 
 	dout("ceph_state_change %p state = %lu sk_state = %u\n",
 	     con, con->state, sk->sk_state);
@@ -184,6 +215,8 @@ static void ceph_state_change(struct sock *sk)
 		dout("ceph_state_change TCP_ESTABLISHED\n");
 		queue_con(con);
 		break;
+	default:	/* Everything else is uninteresting */
+		break;
 	}
 }
 
@@ -194,7 +227,7 @@ static void set_sock_callbacks(struct socket *sock,
 			       struct ceph_connection *con)
 {
 	struct sock *sk = sock->sk;
-	sk->sk_user_data = (void *)con;
+	sk->sk_user_data = con;
 	sk->sk_data_ready = ceph_data_ready;
 	sk->sk_write_space = ceph_write_space;
 	sk->sk_state_change = ceph_state_change;
@@ -208,7 +241,7 @@ static void set_sock_callbacks(struct socket *sock,
 /*
  * initiate connection to a remote socket.
  */
-static struct socket *ceph_tcp_connect(struct ceph_connection *con)
+static int ceph_tcp_connect(struct ceph_connection *con)
 {
 	struct sockaddr_storage *paddr = &con->peer_addr.in_addr;
 	struct socket *sock;
@@ -218,8 +251,7 @@ static struct socket *ceph_tcp_connect(struct ceph_connection *con)
 	ret = sock_create_kern(con->peer_addr.in_addr.ss_family, SOCK_STREAM,
 			       IPPROTO_TCP, &sock);
 	if (ret)
-		return ERR_PTR(ret);
-	con->sock = sock;
+		return ret;
 	sock->sk->sk_allocation = GFP_NOFS;
 
 #ifdef CONFIG_LOCKDEP
@@ -236,19 +268,17 @@ static struct socket *ceph_tcp_connect(struct ceph_connection *con)
 		dout("connect %s EINPROGRESS sk_state = %u\n",
 		     ceph_pr_addr(&con->peer_addr.in_addr),
 		     sock->sk->sk_state);
-		ret = 0;
-	}
-	if (ret < 0) {
+	} else if (ret < 0) {
 		pr_err("connect %s error %d\n",
 		       ceph_pr_addr(&con->peer_addr.in_addr), ret);
 		sock_release(sock);
-		con->sock = NULL;
 		con->error_msg = "connect error";
+
+		return ret;
 	}
+	con->sock = sock;
 
-	if (ret < 0)
-		return ERR_PTR(ret);
-	return sock;
+	return 0;
 }
 
 static int ceph_tcp_recvmsg(struct socket *sock, void *buf, size_t len)
@@ -284,6 +314,19 @@ static int ceph_tcp_sendmsg(struct socket *sock, struct kvec *iov,
 	return r;
 }
 
+static int ceph_tcp_sendpage(struct socket *sock, struct page *page,
+		     int offset, size_t size, int more)
+{
+	int flags = MSG_DONTWAIT | MSG_NOSIGNAL | (more ? MSG_MORE : MSG_EOR);
+	int ret;
+
+	ret = kernel_sendpage(sock, page, offset, size, flags);
+	if (ret == -EAGAIN)
+		ret = 0;
+
+	return ret;
+}
+
 
 /*
  * Shutdown/close the socket for the given connection.
@@ -391,22 +434,23 @@ bool ceph_con_opened(struct ceph_connection *con)
  */
 struct ceph_connection *ceph_con_get(struct ceph_connection *con)
 {
-	dout("con_get %p nref = %d -> %d\n", con,
-	     atomic_read(&con->nref), atomic_read(&con->nref) + 1);
-	if (atomic_inc_not_zero(&con->nref))
-		return con;
-	return NULL;
+	int nref = __atomic_add_unless(&con->nref, 1, 0);
+
+	dout("con_get %p nref = %d -> %d\n", con, nref, nref + 1);
+
+	return nref ? con : NULL;
 }
 
 void ceph_con_put(struct ceph_connection *con)
 {
-	dout("con_put %p nref = %d -> %d\n", con,
-	     atomic_read(&con->nref), atomic_read(&con->nref) - 1);
-	BUG_ON(atomic_read(&con->nref) == 0);
-	if (atomic_dec_and_test(&con->nref)) {
+	int nref = atomic_dec_return(&con->nref);
+
+	BUG_ON(nref < 0);
+	if (nref == 0) {
 		BUG_ON(con->sock);
 		kfree(con);
 	}
+	dout("con_put %p nref = %d -> %d\n", con, nref + 1, nref);
 }
 
 /*
@@ -442,14 +486,35 @@ static u32 get_global_seq(struct ceph_messenger *msgr, u32 gt)
 	return ret;
 }
 
+static void ceph_con_out_kvec_reset(struct ceph_connection *con)
+{
+	con->out_kvec_left = 0;
+	con->out_kvec_bytes = 0;
+	con->out_kvec_cur = &con->out_kvec[0];
+}
+
+static void ceph_con_out_kvec_add(struct ceph_connection *con,
+				size_t size, void *data)
+{
+	int index;
+
+	index = con->out_kvec_left;
+	BUG_ON(index >= ARRAY_SIZE(con->out_kvec));
+
+	con->out_kvec[index].iov_len = size;
+	con->out_kvec[index].iov_base = data;
+	con->out_kvec_left++;
+	con->out_kvec_bytes += size;
+}
 
 /*
  * Prepare footer for currently outgoing message, and finish things
  * off.  Assumes out_kvec* are already valid.. we just add on to the end.
  */
-static void prepare_write_message_footer(struct ceph_connection *con, int v)
+static void prepare_write_message_footer(struct ceph_connection *con)
 {
 	struct ceph_msg *m = con->out_msg;
+	int v = con->out_kvec_left;
 
 	dout("prepare_write_message_footer %p\n", con);
 	con->out_kvec_is_msg = true;
@@ -467,9 +532,9 @@ static void prepare_write_message_footer(struct ceph_connection *con, int v)
 static void prepare_write_message(struct ceph_connection *con)
 {
 	struct ceph_msg *m;
-	int v = 0;
+	u32 crc;
 
-	con->out_kvec_bytes = 0;
+	ceph_con_out_kvec_reset(con);
 	con->out_kvec_is_msg = true;
 	con->out_msg_done = false;
 
@@ -477,16 +542,13 @@ static void prepare_write_message(struct ceph_connection *con)
 	 * TCP packet that's a good thing. */
 	if (con->in_seq > con->in_seq_acked) {
 		con->in_seq_acked = con->in_seq;
-		con->out_kvec[v].iov_base = &tag_ack;
-		con->out_kvec[v++].iov_len = 1;
+		ceph_con_out_kvec_add(con, sizeof (tag_ack), &tag_ack);
 		con->out_temp_ack = cpu_to_le64(con->in_seq_acked);
-		con->out_kvec[v].iov_base = &con->out_temp_ack;
-		con->out_kvec[v++].iov_len = sizeof(con->out_temp_ack);
-		con->out_kvec_bytes = 1 + sizeof(con->out_temp_ack);
+		ceph_con_out_kvec_add(con, sizeof (con->out_temp_ack),
+			&con->out_temp_ack);
 	}
 
-	m = list_first_entry(&con->out_queue,
-		       struct ceph_msg, list_head);
+	m = list_first_entry(&con->out_queue, struct ceph_msg, list_head);
 	con->out_msg = m;
 
 	/* put message on sent list */
@@ -510,30 +572,26 @@ static void prepare_write_message(struct ceph_connection *con)
 	BUG_ON(le32_to_cpu(m->hdr.front_len) != m->front.iov_len);
 
 	/* tag + hdr + front + middle */
-	con->out_kvec[v].iov_base = &tag_msg;
-	con->out_kvec[v++].iov_len = 1;
-	con->out_kvec[v].iov_base = &m->hdr;
-	con->out_kvec[v++].iov_len = sizeof(m->hdr);
-	con->out_kvec[v++] = m->front;
+	ceph_con_out_kvec_add(con, sizeof (tag_msg), &tag_msg);
+	ceph_con_out_kvec_add(con, sizeof (m->hdr), &m->hdr);
+	ceph_con_out_kvec_add(con, m->front.iov_len, m->front.iov_base);
+
 	if (m->middle)
-		con->out_kvec[v++] = m->middle->vec;
-	con->out_kvec_left = v;
-	con->out_kvec_bytes += 1 + sizeof(m->hdr) + m->front.iov_len +
-		(m->middle ? m->middle->vec.iov_len : 0);
-	con->out_kvec_cur = con->out_kvec;
+		ceph_con_out_kvec_add(con, m->middle->vec.iov_len,
+			m->middle->vec.iov_base);
 
 	/* fill in crc (except data pages), footer */
-	con->out_msg->hdr.crc =
-		cpu_to_le32(crc32c(0, (void *)&m->hdr,
-				      sizeof(m->hdr) - sizeof(m->hdr.crc)));
+	crc = crc32c(0, &m->hdr, offsetof(struct ceph_msg_header, crc));
+	con->out_msg->hdr.crc = cpu_to_le32(crc);
 	con->out_msg->footer.flags = CEPH_MSG_FOOTER_COMPLETE;
-	con->out_msg->footer.front_crc =
-		cpu_to_le32(crc32c(0, m->front.iov_base, m->front.iov_len));
-	if (m->middle)
-		con->out_msg->footer.middle_crc =
-			cpu_to_le32(crc32c(0, m->middle->vec.iov_base,
-					   m->middle->vec.iov_len));
-	else
+
+	crc = crc32c(0, m->front.iov_base, m->front.iov_len);
+	con->out_msg->footer.front_crc = cpu_to_le32(crc);
+	if (m->middle) {
+		crc = crc32c(0, m->middle->vec.iov_base,
+				m->middle->vec.iov_len);
+		con->out_msg->footer.middle_crc = cpu_to_le32(crc);
+	} else
 		con->out_msg->footer.middle_crc = 0;
 	con->out_msg->footer.data_crc = 0;
 	dout("prepare_write_message front_crc %u data_crc %u\n",
@@ -549,11 +607,11 @@ static void prepare_write_message(struct ceph_connection *con)
 		else
 			con->out_msg_pos.page_pos = 0;
 		con->out_msg_pos.data_pos = 0;
-		con->out_msg_pos.did_page_crc = 0;
+		con->out_msg_pos.did_page_crc = false;
 		con->out_more = 1;  /* data + footer will follow */
 	} else {
 		/* no, queue up footer too and be done */
-		prepare_write_message_footer(con, v);
+		prepare_write_message_footer(con);
 	}
 
 	set_bit(WRITE_PENDING, &con->state);
@@ -568,14 +626,14 @@ static void prepare_write_ack(struct ceph_connection *con)
 	     con->in_seq_acked, con->in_seq);
 	con->in_seq_acked = con->in_seq;
 
-	con->out_kvec[0].iov_base = &tag_ack;
-	con->out_kvec[0].iov_len = 1;
+	ceph_con_out_kvec_reset(con);
+
+	ceph_con_out_kvec_add(con, sizeof (tag_ack), &tag_ack);
+
 	con->out_temp_ack = cpu_to_le64(con->in_seq_acked);
-	con->out_kvec[1].iov_base = &con->out_temp_ack;
-	con->out_kvec[1].iov_len = sizeof(con->out_temp_ack);
-	con->out_kvec_left = 2;
-	con->out_kvec_bytes = 1 + sizeof(con->out_temp_ack);
-	con->out_kvec_cur = con->out_kvec;
+	ceph_con_out_kvec_add(con, sizeof (con->out_temp_ack),
+				&con->out_temp_ack);
+
 	con->out_more = 1;  /* more will follow.. eventually.. */
 	set_bit(WRITE_PENDING, &con->state);
 }
@@ -586,11 +644,8 @@ static void prepare_write_ack(struct ceph_connection *con)
 static void prepare_write_keepalive(struct ceph_connection *con)
 {
 	dout("prepare_write_keepalive %p\n", con);
-	con->out_kvec[0].iov_base = &tag_keepalive;
-	con->out_kvec[0].iov_len = 1;
-	con->out_kvec_left = 1;
-	con->out_kvec_bytes = 1;
-	con->out_kvec_cur = con->out_kvec;
+	ceph_con_out_kvec_reset(con);
+	ceph_con_out_kvec_add(con, sizeof (tag_keepalive), &tag_keepalive);
 	set_bit(WRITE_PENDING, &con->state);
 }
 
@@ -619,12 +674,9 @@ static int prepare_connect_authorizer(struct ceph_connection *con)
 	con->out_connect.authorizer_protocol = cpu_to_le32(auth_protocol);
 	con->out_connect.authorizer_len = cpu_to_le32(auth_len);
 
-	if (auth_len) {
-		con->out_kvec[con->out_kvec_left].iov_base = auth_buf;
-		con->out_kvec[con->out_kvec_left].iov_len = auth_len;
-		con->out_kvec_left++;
-		con->out_kvec_bytes += auth_len;
-	}
+	if (auth_len)
+		ceph_con_out_kvec_add(con, auth_len, auth_buf);
+
 	return 0;
 }
 
@@ -634,22 +686,18 @@ static int prepare_connect_authorizer(struct ceph_connection *con)
 static void prepare_write_banner(struct ceph_messenger *msgr,
 				 struct ceph_connection *con)
 {
-	int len = strlen(CEPH_BANNER);
+	ceph_con_out_kvec_reset(con);
+	ceph_con_out_kvec_add(con, strlen(CEPH_BANNER), CEPH_BANNER);
+	ceph_con_out_kvec_add(con, sizeof (msgr->my_enc_addr),
+					&msgr->my_enc_addr);
 
-	con->out_kvec[0].iov_base = CEPH_BANNER;
-	con->out_kvec[0].iov_len = len;
-	con->out_kvec[1].iov_base = &msgr->my_enc_addr;
-	con->out_kvec[1].iov_len = sizeof(msgr->my_enc_addr);
-	con->out_kvec_left = 2;
-	con->out_kvec_bytes = len + sizeof(msgr->my_enc_addr);
-	con->out_kvec_cur = con->out_kvec;
 	con->out_more = 0;
 	set_bit(WRITE_PENDING, &con->state);
 }
 
 static int prepare_write_connect(struct ceph_messenger *msgr,
 				 struct ceph_connection *con,
-				 int after_banner)
+				 int include_banner)
 {
 	unsigned global_seq = get_global_seq(con->msgr, 0);
 	int proto;
@@ -678,22 +726,18 @@ static int prepare_write_connect(struct ceph_messenger *msgr,
 	con->out_connect.protocol_version = cpu_to_le32(proto);
 	con->out_connect.flags = 0;
 
-	if (!after_banner) {
-		con->out_kvec_left = 0;
-		con->out_kvec_bytes = 0;
-	}
-	con->out_kvec[con->out_kvec_left].iov_base = &con->out_connect;
-	con->out_kvec[con->out_kvec_left].iov_len = sizeof(con->out_connect);
-	con->out_kvec_left++;
-	con->out_kvec_bytes += sizeof(con->out_connect);
-	con->out_kvec_cur = con->out_kvec;
+	if (include_banner)
+		prepare_write_banner(msgr, con);
+	else
+		ceph_con_out_kvec_reset(con);
+	ceph_con_out_kvec_add(con, sizeof (con->out_connect), &con->out_connect);
+
 	con->out_more = 0;
 	set_bit(WRITE_PENDING, &con->state);
 
 	return prepare_connect_authorizer(con);
 }
 
-
 /*
  * write as much of pending kvecs to the socket as we can.
  *  1 -> done
@@ -714,17 +758,18 @@ static int write_partial_kvec(struct ceph_connection *con)
 		con->out_kvec_bytes -= ret;
 		if (con->out_kvec_bytes == 0)
 			break;            /* done */
-		while (ret > 0) {
-			if (ret >= con->out_kvec_cur->iov_len) {
-				ret -= con->out_kvec_cur->iov_len;
-				con->out_kvec_cur++;
-				con->out_kvec_left--;
-			} else {
-				con->out_kvec_cur->iov_len -= ret;
-				con->out_kvec_cur->iov_base += ret;
-				ret = 0;
-				break;
-			}
+
+		/* account for full iov entries consumed */
+		while (ret >= con->out_kvec_cur->iov_len) {
+			BUG_ON(!con->out_kvec_left);
+			ret -= con->out_kvec_cur->iov_len;
+			con->out_kvec_cur++;
+			con->out_kvec_left--;
+		}
+		/* and for a partially-consumed entry */
+		if (ret) {
+			con->out_kvec_cur->iov_len -= ret;
+			con->out_kvec_cur->iov_base += ret;
 		}
 	}
 	con->out_kvec_left = 0;
@@ -773,7 +818,7 @@ static int write_partial_msg_pages(struct ceph_connection *con)
 	struct ceph_msg *msg = con->out_msg;
 	unsigned data_len = le32_to_cpu(msg->hdr.data_len);
 	size_t len;
-	int crc = con->msgr->nocrc;
+	bool do_datacrc = !con->msgr->nocrc;
 	int ret;
 	int total_max_write;
 	int in_trail = 0;
@@ -790,9 +835,8 @@ static int write_partial_msg_pages(struct ceph_connection *con)
 
 	while (data_len > con->out_msg_pos.data_pos) {
 		struct page *page = NULL;
-		void *kaddr = NULL;
 		int max_write = PAGE_SIZE;
-		int page_shift = 0;
+		int bio_offset = 0;
 
 		total_max_write = data_len - trail_len -
 			con->out_msg_pos.data_pos;
@@ -811,58 +855,47 @@ static int write_partial_msg_pages(struct ceph_connection *con)
 
 			page = list_first_entry(&msg->trail->head,
 						struct page, lru);
-			if (crc)
-				kaddr = kmap(page);
 			max_write = PAGE_SIZE;
 		} else if (msg->pages) {
 			page = msg->pages[con->out_msg_pos.page];
-			if (crc)
-				kaddr = kmap(page);
 		} else if (msg->pagelist) {
 			page = list_first_entry(&msg->pagelist->head,
 						struct page, lru);
-			if (crc)
-				kaddr = kmap(page);
 #ifdef CONFIG_BLOCK
 		} else if (msg->bio) {
 			struct bio_vec *bv;
 
 			bv = bio_iovec_idx(msg->bio_iter, msg->bio_seg);
 			page = bv->bv_page;
-			page_shift = bv->bv_offset;
-			if (crc)
-				kaddr = kmap(page) + page_shift;
+			bio_offset = bv->bv_offset;
 			max_write = bv->bv_len;
 #endif
 		} else {
-			page = con->msgr->zero_page;
-			if (crc)
-				kaddr = page_address(con->msgr->zero_page);
+			page = zero_page;
 		}
 		len = min_t(int, max_write - con->out_msg_pos.page_pos,
 			    total_max_write);
 
-		if (crc && !con->out_msg_pos.did_page_crc) {
-			void *base = kaddr + con->out_msg_pos.page_pos;
+		if (do_datacrc && !con->out_msg_pos.did_page_crc) {
+			void *base;
+			u32 crc;
 			u32 tmpcrc = le32_to_cpu(con->out_msg->footer.data_crc);
+			char *kaddr;
 
+			kaddr = kmap(page);
 			BUG_ON(kaddr == NULL);
-			con->out_msg->footer.data_crc =
-				cpu_to_le32(crc32c(tmpcrc, base, len));
-			con->out_msg_pos.did_page_crc = 1;
+			base = kaddr + con->out_msg_pos.page_pos + bio_offset;
+			crc = crc32c(tmpcrc, base, len);
+			con->out_msg->footer.data_crc = cpu_to_le32(crc);
+			con->out_msg_pos.did_page_crc = true;
 		}
-		ret = kernel_sendpage(con->sock, page,
-				      con->out_msg_pos.page_pos + page_shift,
-				      len,
-				      MSG_DONTWAIT | MSG_NOSIGNAL |
-				      MSG_MORE);
-
-		if (crc &&
-		    (msg->pages || msg->pagelist || msg->bio || in_trail))
+		ret = ceph_tcp_sendpage(con->sock, page,
+				      con->out_msg_pos.page_pos + bio_offset,
+				      len, 1);
+
+		if (do_datacrc)
 			kunmap(page);
 
-		if (ret == -EAGAIN)
-			ret = 0;
 		if (ret <= 0)
 			goto out;
 
@@ -871,7 +904,7 @@ static int write_partial_msg_pages(struct ceph_connection *con)
 		if (ret == len) {
 			con->out_msg_pos.page_pos = 0;
 			con->out_msg_pos.page++;
-			con->out_msg_pos.did_page_crc = 0;
+			con->out_msg_pos.did_page_crc = false;
 			if (in_trail)
 				list_move_tail(&page->lru,
 					       &msg->trail->head);
@@ -888,12 +921,10 @@ static int write_partial_msg_pages(struct ceph_connection *con)
 	dout("write_partial_msg_pages %p msg %p done\n", con, msg);
 
 	/* prepare and queue up footer, too */
-	if (!crc)
+	if (!do_datacrc)
 		con->out_msg->footer.flags |= CEPH_MSG_FOOTER_NOCRC;
-	con->out_kvec_bytes = 0;
-	con->out_kvec_left = 0;
-	con->out_kvec_cur = con->out_kvec;
-	prepare_write_message_footer(con, 0);
+	ceph_con_out_kvec_reset(con);
+	prepare_write_message_footer(con);
 	ret = 1;
 out:
 	return ret;
@@ -907,12 +938,9 @@ static int write_partial_skip(struct ceph_connection *con)
 	int ret;
 
 	while (con->out_skip > 0) {
-		struct kvec iov = {
-			.iov_base = page_address(con->msgr->zero_page),
-			.iov_len = min(con->out_skip, (int)PAGE_CACHE_SIZE)
-		};
+		size_t size = min(con->out_skip, (int) PAGE_CACHE_SIZE);
 
-		ret = ceph_tcp_sendmsg(con->sock, &iov, 1, iov.iov_len, 1);
+		ret = ceph_tcp_sendpage(con->sock, zero_page, 0, size, 1);
 		if (ret <= 0)
 			goto out;
 		con->out_skip -= ret;
@@ -1085,8 +1113,8 @@ static void addr_set_port(struct sockaddr_storage *ss, int p)
 static int ceph_pton(const char *str, size_t len, struct sockaddr_storage *ss,
 		char delim, const char **ipend)
 {
-	struct sockaddr_in *in4 = (void *)ss;
-	struct sockaddr_in6 *in6 = (void *)ss;
+	struct sockaddr_in *in4 = (struct sockaddr_in *) ss;
+	struct sockaddr_in6 *in6 = (struct sockaddr_in6 *) ss;
 
 	memset(ss, 0, sizeof(*ss));
 
@@ -1512,10 +1540,9 @@ static int read_partial_message_section(struct ceph_connection *con,
 		if (ret <= 0)
 			return ret;
 		section->iov_len += ret;
-		if (section->iov_len == sec_len)
-			*crc = crc32c(0, section->iov_base,
-				      section->iov_len);
 	}
+	if (section->iov_len == sec_len)
+		*crc = crc32c(0, section->iov_base, section->iov_len);
 
 	return 1;
 }
@@ -1527,7 +1554,7 @@ static struct ceph_msg *ceph_alloc_msg(struct ceph_connection *con,
 
 static int read_partial_message_pages(struct ceph_connection *con,
 				      struct page **pages,
-				      unsigned data_len, int datacrc)
+				      unsigned data_len, bool do_datacrc)
 {
 	void *p;
 	int ret;
@@ -1540,7 +1567,7 @@ static int read_partial_message_pages(struct ceph_connection *con,
 	p = kmap(pages[con->in_msg_pos.page]);
 	ret = ceph_tcp_recvmsg(con->sock, p + con->in_msg_pos.page_pos,
 			       left);
-	if (ret > 0 && datacrc)
+	if (ret > 0 && do_datacrc)
 		con->in_data_crc =
 			crc32c(con->in_data_crc,
 				  p + con->in_msg_pos.page_pos, ret);
@@ -1560,7 +1587,7 @@ static int read_partial_message_pages(struct ceph_connection *con,
 #ifdef CONFIG_BLOCK
 static int read_partial_message_bio(struct ceph_connection *con,
 				    struct bio **bio_iter, int *bio_seg,
-				    unsigned data_len, int datacrc)
+				    unsigned data_len, bool do_datacrc)
 {
 	struct bio_vec *bv = bio_iovec_idx(*bio_iter, *bio_seg);
 	void *p;
@@ -1576,7 +1603,7 @@ static int read_partial_message_bio(struct ceph_connection *con,
 
 	ret = ceph_tcp_recvmsg(con->sock, p + con->in_msg_pos.page_pos,
 			       left);
-	if (ret > 0 && datacrc)
+	if (ret > 0 && do_datacrc)
 		con->in_data_crc =
 			crc32c(con->in_data_crc,
 				  p + con->in_msg_pos.page_pos, ret);
@@ -1603,9 +1630,10 @@ static int read_partial_message(struct ceph_connection *con)
 	int ret;
 	int to, left;
 	unsigned front_len, middle_len, data_len;
-	int datacrc = con->msgr->nocrc;
+	bool do_datacrc = !con->msgr->nocrc;
 	int skip;
 	u64 seq;
+	u32 crc;
 
 	dout("read_partial_message con %p msg %p\n", con, m);
 
@@ -1618,17 +1646,16 @@ static int read_partial_message(struct ceph_connection *con)
 		if (ret <= 0)
 			return ret;
 		con->in_base_pos += ret;
-		if (con->in_base_pos == sizeof(con->in_hdr)) {
-			u32 crc = crc32c(0, (void *)&con->in_hdr,
-				 sizeof(con->in_hdr) - sizeof(con->in_hdr.crc));
-			if (crc != le32_to_cpu(con->in_hdr.crc)) {
-				pr_err("read_partial_message bad hdr "
-				       " crc %u != expected %u\n",
-				       crc, con->in_hdr.crc);
-				return -EBADMSG;
-			}
-		}
 	}
+
+	crc = crc32c(0, &con->in_hdr, offsetof(struct ceph_msg_header, crc));
+	if (cpu_to_le32(crc) != con->in_hdr.crc) {
+		pr_err("read_partial_message bad hdr "
+		       " crc %u != expected %u\n",
+		       crc, con->in_hdr.crc);
+		return -EBADMSG;
+	}
+
 	front_len = le32_to_cpu(con->in_hdr.front_len);
 	if (front_len > CEPH_MSG_MAX_FRONT_LEN)
 		return -EIO;
@@ -1714,7 +1741,7 @@ static int read_partial_message(struct ceph_connection *con)
 	while (con->in_msg_pos.data_pos < data_len) {
 		if (m->pages) {
 			ret = read_partial_message_pages(con, m->pages,
-						 data_len, datacrc);
+						 data_len, do_datacrc);
 			if (ret <= 0)
 				return ret;
 #ifdef CONFIG_BLOCK
@@ -1722,7 +1749,7 @@ static int read_partial_message(struct ceph_connection *con)
 
 			ret = read_partial_message_bio(con,
 						 &m->bio_iter, &m->bio_seg,
-						 data_len, datacrc);
+						 data_len, do_datacrc);
 			if (ret <= 0)
 				return ret;
 #endif
@@ -1757,7 +1784,7 @@ static int read_partial_message(struct ceph_connection *con)
 		       m, con->in_middle_crc, m->footer.middle_crc);
 		return -EBADMSG;
 	}
-	if (datacrc &&
+	if (do_datacrc &&
 	    (m->footer.flags & CEPH_MSG_FOOTER_NOCRC) == 0 &&
 	    con->in_data_crc != le32_to_cpu(m->footer.data_crc)) {
 		pr_err("read_partial_message %p data crc %u != exp. %u\n", m,
@@ -1819,7 +1846,6 @@ more:
 
 	/* open the socket first? */
 	if (con->sock == NULL) {
-		prepare_write_banner(msgr, con);
 		prepare_write_connect(msgr, con, 1);
 		prepare_read_banner(con);
 		set_bit(CONNECTING, &con->state);
@@ -1829,11 +1855,9 @@ more:
 		con->in_tag = CEPH_MSGR_TAG_READY;
 		dout("try_write initiating connect on %p new state %lu\n",
 		     con, con->state);
-		con->sock = ceph_tcp_connect(con);
-		if (IS_ERR(con->sock)) {
-			con->sock = NULL;
+		ret = ceph_tcp_connect(con);
+		if (ret < 0) {
 			con->error_msg = "connect error";
-			ret = -1;
 			goto out;
 		}
 	}
@@ -1953,8 +1977,9 @@ more:
 		 *
 		 * FIXME: there must be a better way to do this!
 		 */
-		static char buf[1024];
-		int skip = min(1024, -con->in_base_pos);
+		static char buf[SKIP_BUF_SIZE];
+		int skip = min((int) sizeof (buf), -con->in_base_pos);
+
 		dout("skipping %d / %d bytes\n", skip, -con->in_base_pos);
 		ret = ceph_tcp_recvmsg(con->sock, buf, skip);
 		if (ret <= 0)
@@ -2216,15 +2241,6 @@ struct ceph_messenger *ceph_messenger_create(struct ceph_entity_addr *myaddr,
 
 	spin_lock_init(&msgr->global_seq_lock);
 
-	/* the zero page is needed if a request is "canceled" while the message
-	 * is being written over the socket */
-	msgr->zero_page = __page_cache_alloc(GFP_KERNEL | __GFP_ZERO);
-	if (!msgr->zero_page) {
-		kfree(msgr);
-		return ERR_PTR(-ENOMEM);
-	}
-	kmap(msgr->zero_page);
-
 	if (myaddr)
 		msgr->inst.addr = *myaddr;
 
@@ -2241,8 +2257,6 @@ EXPORT_SYMBOL(ceph_messenger_create);
 void ceph_messenger_destroy(struct ceph_messenger *msgr)
 {
 	dout("destroy %p\n", msgr);
-	kunmap(msgr->zero_page);
-	__free_page(msgr->zero_page);
 	kfree(msgr);
 	dout("destroyed messenger %p\n", msgr);
 }