Message-Id: <4e1debaf32e33a5da0629e10eb371aedec81eb56.1451558672.git.tst@schoebel-theuer.de>
Date:	Thu, 31 Dec 2015 12:36:18 +0100
From:	Thomas Schoebel-Theuer <tst@...oebel-theuer.de>
To:	linux-kernel@...r.kernel.org, tst@...oebel-theuer.de
Subject: [RFC 23/31] mars: add new module xio_server

Signed-off-by: Thomas Schoebel-Theuer <tst@...oebel-theuer.de>
---
 drivers/staging/mars/xio_bricks/xio_server.c | 486 +++++++++++++++++++++++++++
 include/linux/xio/xio_server.h               |  91 +++++
 2 files changed, 577 insertions(+)
 create mode 100644 drivers/staging/mars/xio_bricks/xio_server.c
 create mode 100644 include/linux/xio/xio_server.h

diff --git a/drivers/staging/mars/xio_bricks/xio_server.c b/drivers/staging/mars/xio_bricks/xio_server.c
new file mode 100644
index 0000000..95a3327
--- /dev/null
+++ b/drivers/staging/mars/xio_bricks/xio_server.c
@@ -0,0 +1,486 @@
+/*
+ * MARS Long Distance Replication Software
+ *
+ * Copyright (C) 2010-2014 Thomas Schoebel-Theuer
+ * Copyright (C) 2011-2014 1&1 Internet AG
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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 for more details.
+ */
+
+/*  Server brick (just for demonstration) */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/string.h>
+
+#include <linux/brick/brick.h>
+#include <linux/xio/xio.h>
+#include <linux/xio/xio_bio.h>
+#include <linux/xio/xio_sio.h>
+
+/************************ own type definitions ***********************/
+
+#include <linux/xio/xio_server.h>
+
+static struct xio_socket server_socket[NR_SERVER_SOCKETS];
+static struct task_struct *server_threads[NR_SERVER_SOCKETS];
+
+/************************ own helper functions ***********************/
+
+int cb_thread(void *data)
+{
+	struct server_brick *brick = data;
+	struct xio_socket *sock = &brick->handler_socket;
+	bool aborted = false;
+	bool ok = xio_get_socket(sock);
+	int status = -EINVAL;
+
+	XIO_DBG("--------------- cb_thread starting on socket #%d, ok = %d\n", sock->s_debug_nr, ok);
+	if (!ok)
+		goto done;
+
+	brick->cb_running = true;
+	wake_up_interruptible(&brick->startup_event);
+
+	while (!brick_thread_should_stop() || !list_empty(&brick->cb_read_list) || !list_empty(&brick->cb_write_list) || atomic_read(&brick->in_flight) > 0) {
+		struct server_aio_aspect *aio_a;
+		struct aio_object *aio;
+		struct list_head *tmp;
+		unsigned long flags;
+
+		wait_event_interruptible_timeout(
+			brick->cb_event,
+			!list_empty(&brick->cb_read_list) ||
+			!list_empty(&brick->cb_write_list),
+			1 * HZ);
+
+		spin_lock_irqsave(&brick->cb_lock, flags);
+		tmp = brick->cb_write_list.next;
+		if (tmp == &brick->cb_write_list) {
+			tmp = brick->cb_read_list.next;
+			if (tmp == &brick->cb_read_list) {
+				spin_unlock_irqrestore(&brick->cb_lock, flags);
+				brick_msleep(1000 / HZ);
+				continue;
+			}
+		}
+		list_del_init(tmp);
+		spin_unlock_irqrestore(&brick->cb_lock, flags);
+
+		aio_a = container_of(tmp, struct server_aio_aspect, cb_head);
+		aio = aio_a->object;
+		status = -EINVAL;
+		CHECK_PTR(aio, err);
+
+		status = 0;
+		/* Report a remote error when consistency cannot be guaranteed,
+		 * e.g. emergency mode during sync.
+		 */
+		if (brick->conn_brick && brick->conn_brick->mode_ptr && *brick->conn_brick->mode_ptr < 0
+		    && aio->object_cb)
+			aio->object_cb->cb_error = *brick->conn_brick->mode_ptr;
+		if (!aborted) {
+			down(&brick->socket_sem);
+			status = xio_send_cb(sock, aio);
+			up(&brick->socket_sem);
+		}
+
+err:
+		if (unlikely(status < 0) && !aborted) {
+			aborted = true;
+			XIO_WRN("cannot send response, status = %d\n", status);
+			/* Just shutdown the socket and forget all pending
+			 * requests.
+			 * The _client_ is responsible for resending
+			 * any lost operations.
+			 */
+			xio_shutdown_socket(sock);
+		}
+
+		if (aio_a->data) {
+			brick_block_free(aio_a->data, aio_a->len);
+			aio->io_data = NULL;
+		}
+		if (aio_a->do_put) {
+			GENERIC_INPUT_CALL(brick->inputs[0], aio_put, aio);
+			atomic_dec(&brick->in_flight);
+		} else {
+			obj_free(aio);
+		}
+	}
+
+	xio_shutdown_socket(sock);
+	xio_put_socket(sock);
+
+done:
+	XIO_DBG("---------- cb_thread terminating, status = %d\n", status);
+	wake_up_interruptible(&brick->startup_event);
+	return status;
+}
+
+static
+void server_endio(struct generic_callback *cb)
+{
+	struct server_aio_aspect *aio_a;
+	struct aio_object *aio;
+	struct server_brick *brick;
+	int rw;
+	unsigned long flags;
+
+	aio_a = cb->cb_private;
+	CHECK_PTR(aio_a, err);
+	aio = aio_a->object;
+	CHECK_PTR(aio, err);
+	LAST_CALLBACK(cb);
+	if (unlikely(cb != &aio->_object_cb))
+		XIO_ERR("bad cb pointer %p != %p\n", cb, &aio->_object_cb);
+
+	brick = aio_a->brick;
+	if (unlikely(!brick)) {
+		XIO_WRN("late IO callback -- cannot do anything\n");
+		goto out_return;
+	}
+
+	rw = aio->io_rw;
+
+	spin_lock_irqsave(&brick->cb_lock, flags);
+	if (rw)
+		list_add_tail(&aio_a->cb_head, &brick->cb_write_list);
+	else
+		list_add_tail(&aio_a->cb_head, &brick->cb_read_list);
+	spin_unlock_irqrestore(&brick->cb_lock, flags);
+
+	wake_up_interruptible(&brick->cb_event);
+	goto out_return;
+err:
+	XIO_FAT("cannot handle callback - giving up\n");
+out_return:;
+}
+
+int server_io(struct server_brick *brick, struct xio_socket *sock, struct xio_cmd *cmd)
+{
+	struct aio_object *aio;
+	struct server_aio_aspect *aio_a;
+	int amount;
+	int status = -ENOTRECOVERABLE;
+
+	if (!brick->cb_running || !brick->handler_running || !xio_socket_is_alive(sock))
+		goto done;
+
+	aio = server_alloc_aio(brick);
+	status = -ENOMEM;
+	aio_a = server_aio_get_aspect(brick, aio);
+	if (unlikely(!aio_a)) {
+		obj_free(aio);
+		goto done;
+	}
+
+	status = xio_recv_aio(sock, aio, cmd);
+	if (status < 0) {
+		obj_free(aio);
+		goto done;
+	}
+
+	aio_a->brick = brick;
+	aio_a->data = aio->io_data;
+	aio_a->len = aio->io_len;
+	SETUP_CALLBACK(aio, server_endio, aio_a);
+
+	amount = 0;
+	if (!aio->io_cs_mode < 2)
+		amount = (aio->io_len - 1) / 1024 + 1;
+	rate_limit_sleep(&server_limiter, amount);
+
+	status = GENERIC_INPUT_CALL(brick->inputs[0], aio_get, aio);
+	if (unlikely(status < 0)) {
+		XIO_WRN("aio_get execution error = %d\n", status);
+		SIMPLE_CALLBACK(aio, status);
+		status = 0; /*	continue serving requests */
+		goto done;
+	}
+	aio_a->do_put = true;
+	atomic_inc(&brick->in_flight);
+	GENERIC_INPUT_CALL(brick->inputs[0], aio_io, aio);
+
+done:
+	return status;
+}
+
+/***************** own brick * input * output operations *****************/
+
+static int server_get_info(struct server_output *output, struct xio_info *info)
+{
+	struct server_input *input = output->brick->inputs[0];
+
+	return GENERIC_INPUT_CALL(input, xio_get_info, info);
+}
+
+static int server_io_get(struct server_output *output, struct aio_object *aio)
+{
+	struct server_input *input = output->brick->inputs[0];
+
+	return GENERIC_INPUT_CALL(input, aio_get, aio);
+}
+
+static void server_io_put(struct server_output *output, struct aio_object *aio)
+{
+	struct server_input *input = output->brick->inputs[0];
+
+	GENERIC_INPUT_CALL(input, aio_put, aio);
+}
+
+static void server_io_io(struct server_output *output, struct aio_object *aio)
+{
+	struct server_input *input = output->brick->inputs[0];
+
+	GENERIC_INPUT_CALL(input, aio_io, aio);
+}
+
+int server_switch(struct server_brick *brick)
+{
+	struct xio_socket *sock = &brick->handler_socket;
+	int status = 0;
+
+	if (brick->power.button) {
+		static int version;
+		bool ok;
+
+		if (brick->power.on_led)
+			goto done;
+
+		ok = xio_get_socket(sock);
+		if (unlikely(!ok)) {
+			status = -ENOENT;
+			goto err;
+		}
+
+		xio_set_power_off_led((void *)brick, false);
+
+		brick->version = version++;
+		brick->handler_thread = brick_thread_create(handler_thread, brick, "xio_handler%d", brick->version);
+		if (unlikely(!brick->handler_thread)) {
+			XIO_ERR("cannot create handler thread\n");
+			status = -ENOENT;
+			goto err;
+		}
+
+		xio_set_power_on_led((void *)brick, true);
+	} else if (!brick->power.off_led) {
+		struct task_struct *thread;
+
+		xio_set_power_on_led((void *)brick, false);
+
+		xio_shutdown_socket(sock);
+
+		thread = brick->handler_thread;
+		if (thread) {
+			brick->handler_thread = NULL;
+			brick->handler_running = false;
+			XIO_DBG("#%d stopping handler thread....\n", sock->s_debug_nr);
+			brick_thread_stop(thread);
+		}
+
+		xio_put_socket(sock);
+		XIO_DBG("#%d socket s_count = %d\n", sock->s_debug_nr, atomic_read(&sock->s_count));
+
+		xio_set_power_off_led((void *)brick, true);
+	}
+err:
+	if (unlikely(status < 0)) {
+		xio_set_power_off_led((void *)brick, true);
+		xio_shutdown_socket(sock);
+		xio_put_socket(sock);
+	}
+done:
+	return status;
+}
+
+/*************** informational * statistics **************/
+
+static
+char *server_statistics(struct server_brick *brick, int verbose)
+{
+	char *res = brick_string_alloc(1024);
+
+	snprintf(res, 1024,
+		 "cb_running = %d handler_running = %d in_flight = %d\n",
+		 brick->cb_running,
+		 brick->handler_running,
+		 atomic_read(&brick->in_flight));
+
+	return res;
+}
+
+static
+void server_reset_statistics(struct server_brick *brick)
+{
+}
+
+/*************** object * aspect constructors * destructors **************/
+
+static int server_aio_aspect_init_fn(struct generic_aspect *_ini)
+{
+	struct server_aio_aspect *ini = (void *)_ini;
+
+	INIT_LIST_HEAD(&ini->cb_head);
+	return 0;
+}
+
+static void server_aio_aspect_exit_fn(struct generic_aspect *_ini)
+{
+	struct server_aio_aspect *ini = (void *)_ini;
+
+	CHECK_HEAD_EMPTY(&ini->cb_head);
+}
+
+XIO_MAKE_STATICS(server);
+
+/********************* brick constructors * destructors *******************/
+
+static int server_brick_construct(struct server_brick *brick)
+{
+	init_waitqueue_head(&brick->startup_event);
+	init_waitqueue_head(&brick->cb_event);
+	sema_init(&brick->socket_sem, 1);
+	spin_lock_init(&brick->cb_lock);
+	INIT_LIST_HEAD(&brick->cb_read_list);
+	INIT_LIST_HEAD(&brick->cb_write_list);
+	return 0;
+}
+
+static int server_brick_destruct(struct server_brick *brick)
+{
+	CHECK_HEAD_EMPTY(&brick->cb_read_list);
+	CHECK_HEAD_EMPTY(&brick->cb_write_list);
+	return 0;
+}
+
+static int server_output_construct(struct server_output *output)
+{
+	return 0;
+}
+
+/************************ static structs ***********************/
+
+static struct server_brick_ops server_brick_ops = {
+	.brick_switch = server_switch,
+	.brick_statistics = server_statistics,
+	.reset_statistics = server_reset_statistics,
+};
+
+static struct server_output_ops server_output_ops = {
+	.xio_get_info = server_get_info,
+	.aio_get = server_io_get,
+	.aio_put = server_io_put,
+	.aio_io = server_io_io,
+};
+
+const struct server_input_type server_input_type = {
+	.type_name = "server_input",
+	.input_size = sizeof(struct server_input),
+};
+
+static const struct server_input_type *server_input_types[] = {
+	&server_input_type,
+};
+
+const struct server_output_type server_output_type = {
+	.type_name = "server_output",
+	.output_size = sizeof(struct server_output),
+	.master_ops = &server_output_ops,
+	.output_construct = &server_output_construct,
+};
+
+static const struct server_output_type *server_output_types[] = {
+	&server_output_type,
+};
+
+const struct server_brick_type server_brick_type = {
+	.type_name = "server_brick",
+	.brick_size = sizeof(struct server_brick),
+	.max_inputs = 1,
+	.max_outputs = 0,
+	.master_ops = &server_brick_ops,
+	.aspect_types = server_aspect_types,
+	.default_input_types = server_input_types,
+	.default_output_types = server_output_types,
+	.brick_construct = &server_brick_construct,
+	.brick_destruct = &server_brick_destruct,
+};
+
+/*********************************************************************/
+
+/*  strategy layer */
+
+int server_show_statist;
+
+/***************** module init stuff ************************/
+
+struct rate_limiter server_limiter = {
+	.lim_max_rate = 0,
+};
+
+void exit_xio_server(void)
+{
+	int i;
+
+	XIO_INF("exit_server()\n");
+	server_unregister_brick_type();
+
+	for (i = 0; i < NR_SERVER_SOCKETS; i++) {
+		if (server_threads[i]) {
+			XIO_INF("stopping server thread %d...\n", i);
+			brick_thread_stop(server_threads[i]);
+		}
+		XIO_INF("closing server socket %d...\n", i);
+		xio_put_socket(&server_socket[i]);
+	}
+}
+
+int __init init_xio_server(void)
+{
+	int i;
+
+	XIO_INF("init_server()\n");
+
+	for (i = 0; i < NR_SERVER_SOCKETS; i++) {
+		struct sockaddr_storage sockaddr = {};
+		char tmp[64];
+		int status;
+
+		if (xio_translate_hostname)
+			snprintf(tmp, sizeof(tmp), "%s:%d", my_id(), xio_net_default_port + i);
+		else
+			snprintf(tmp, sizeof(tmp), ":%d", xio_net_default_port + i);
+
+		status = xio_create_sockaddr(&sockaddr, tmp);
+		if (unlikely(status < 0)) {
+			exit_xio_server();
+			return status;
+		}
+
+		status = xio_create_socket(&server_socket[i], &sockaddr, NULL);
+		if (unlikely(status < 0)) {
+			XIO_ERR("could not create server socket %d, status = %d\n", i, status);
+			exit_xio_server();
+			return status;
+		}
+
+		server_threads[i] = brick_thread_create(server_thread, &server_socket[i], "xio_server_%d", i);
+		if (unlikely(!server_threads[i] || IS_ERR(server_threads[i]))) {
+			XIO_ERR("could not create server thread %d\n", i);
+			exit_xio_server();
+			return -ENOENT;
+		}
+	}
+
+	return server_register_brick_type();
+}
diff --git a/include/linux/xio/xio_server.h b/include/linux/xio/xio_server.h
new file mode 100644
index 0000000..2c13f26
--- /dev/null
+++ b/include/linux/xio/xio_server.h
@@ -0,0 +1,91 @@
+/*
+ * MARS Long Distance Replication Software
+ *
+ * Copyright (C) 2010-2014 Thomas Schoebel-Theuer
+ * Copyright (C) 2011-2014 1&1 Internet AG
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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 for more details.
+ */
+
+#ifndef XIO_SERVER_H
+#define XIO_SERVER_H
+
+#include <linux/wait.h>
+
+#include <linux/xio/xio_net.h>
+#include <linux/brick/lib_limiter.h>
+
+#define NR_SERVER_SOCKETS		3
+
+extern int server_show_statist;
+
+extern struct rate_limiter server_limiter;
+
+struct server_aio_aspect {
+	GENERIC_ASPECT(aio);
+	struct server_brick *brick;
+	struct list_head cb_head;
+	void *data;
+	int len;
+	bool do_put;
+};
+
+struct server_output {
+	XIO_OUTPUT(server);
+};
+
+struct server_brick {
+	XIO_BRICK(server);
+	struct semaphore socket_sem;
+	struct xio_socket handler_socket;
+	struct xio_brick *conn_brick;
+	struct task_struct *handler_thread;
+	struct task_struct *cb_thread;
+
+	wait_queue_head_t startup_event;
+	wait_queue_head_t cb_event;
+	spinlock_t cb_lock;
+	struct list_head cb_read_list;
+	struct list_head cb_write_list;
+	atomic_t in_flight;
+	int version;
+	bool cb_running;
+	bool handler_running;
+};
+
+struct server_input {
+	XIO_INPUT(server);
+};
+
+XIO_TYPES(server);
+
+/* Internal interface to specific implementations.
+ * This is used for a rough separation of the strategy layer
+ * from the ordinary XIO layer.
+ * Currently, separation is at linker level.
+ * TODO: implement a dynamic separation later.
+ */
+
+/* Implemented separately, used by generic part */
+
+extern int server_thread(void *data);
+
+extern int handler_thread(void *data);
+
+extern int cb_thread(void *data);
+
+extern int server_io(struct server_brick *brick, struct xio_socket *sock, struct xio_cmd *cmd);
+
+/* Implemented by generic part, used by specific part */
+
+extern int server_switch(struct server_brick *brick);
+
+#endif
-- 
2.6.4

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