Date:   Fri, 30 Dec 2016 23:57:44 +0100
From:   Thomas Schoebel-Theuer <tst@...oebel-theuer.de>
To:     linux-kernel@...r.kernel.org, tst@...oebel-theuer.de
Subject: [RFC 18/32] mars: add new module xio_sio

Signed-off-by: Thomas Schoebel-Theuer <tst@...oebel-theuer.de>
---
 drivers/staging/mars/xio_bricks/xio_sio.c | 578 ++++++++++++++++++++++++++++++
 include/linux/xio/xio_sio.h               |  68 ++++
 2 files changed, 646 insertions(+)
 create mode 100644 drivers/staging/mars/xio_bricks/xio_sio.c
 create mode 100644 include/linux/xio/xio_sio.h

diff --git a/drivers/staging/mars/xio_bricks/xio_sio.c b/drivers/staging/mars/xio_bricks/xio_sio.c
new file mode 100644
index 000000000000..c910cbda2ae5
--- /dev/null
+++ b/drivers/staging/mars/xio_bricks/xio_sio.c
@@ -0,0 +1,578 @@
+/*
+ * 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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/version.h>
+#include <linux/string.h>
+#include <linux/list.h>
+#include <linux/types.h>
+#include <linux/blkdev.h>
+#include <linux/highmem.h>
+#include <linux/spinlock.h>
+#include <linux/wait.h>
+
+#include <linux/xio/xio.h>
+
+/************************ own type definitions ***********************/
+
+#include <linux/xio/xio_sio.h>
+
+/***************** own brick * input * output operations *****************/
+
+static int sio_io_get(struct sio_output *output, struct aio_object *aio)
+{
+	struct file *file;
+
+	if (unlikely(!output->brick->power.on_led))
+		return -EBADFD;
+
+	if (aio->obj_initialized) {
+		obj_get(aio);
+		return aio->io_len;
+	}
+
+	file = output->mf->mf_filp;
+	if (file) {
+		loff_t total_size = i_size_read(file->f_mapping->host);
+
+		aio->io_total_size = total_size;
+		/* Only check reads.
+		 * Writes behind EOF are always allowed (sparse files)
+		 */
+		if (!aio->io_may_write) {
+			loff_t len = total_size - aio->io_pos;
+
+			if (unlikely(len <= 0)) {
+				/* Special case: allow reads starting _exactly_ at EOF when a timeout is specified.
+				 */
+				if (len < 0 || aio->io_timeout <= 0) {
+					XIO_DBG("ENODATA %lld\n", len);
+					return -ENODATA;
+				}
+			}
+			/*  Shorten below EOF, but allow special case */
+			if (aio->io_len > len && len > 0)
+				aio->io_len = len;
+		}
+	}
+
+	/* Buffered IO.
+	 */
+	if (!aio->io_data) {
+		struct sio_aio_aspect *aio_a = sio_aio_get_aspect(output->brick, aio);
+
+		if (unlikely(!aio_a))
+			return -EILSEQ;
+		if (unlikely(aio->io_len <= 0)) {
+			XIO_ERR("bad io_len = %d\n", aio->io_len);
+			return -ENOMEM;
+		}
+		aio->io_data = brick_block_alloc(aio->io_pos, (aio_a->alloc_len = aio->io_len));
+		aio_a->do_dealloc = true;
+		/* atomic_inc(&output->total_alloc_count); */
+		/* atomic_inc(&output->alloc_count); */
+	}
+
+	obj_get_first(aio);
+	return aio->io_len;
+}
+
+static void sio_io_put(struct sio_output *output, struct aio_object *aio)
+{
+	struct file *file;
+	struct sio_aio_aspect *aio_a;
+
+	if (!obj_put(aio))
+		goto out_return;
+	file = output->mf->mf_filp;
+	aio->io_total_size = i_size_read(file->f_mapping->host);
+
+	aio_a = sio_aio_get_aspect(output->brick, aio);
+	if (aio_a && aio_a->do_dealloc) {
+		brick_block_free(aio->io_data, aio_a->alloc_len);
+		/* atomic_dec(&output->alloc_count); */
+	}
+
+	obj_free(aio);
+out_return:;
+}
+
+static
+int write_aops(struct sio_output *output, struct aio_object *aio)
+{
+	struct file *file = output->mf->mf_filp;
+	loff_t pos = aio->io_pos;
+	void *data = aio->io_data;
+	int  len = aio->io_len;
+	int ret = 0;
+
+	mm_segment_t oldfs;
+
+	oldfs = get_fs();
+	set_fs(get_ds());
+	ret = vfs_write(file, data, len, &pos);
+	set_fs(oldfs);
+	return ret;
+}
+
+static
+int read_aops(struct sio_output *output, struct aio_object *aio)
+{
+	loff_t pos = aio->io_pos;
+	int len = aio->io_len;
+	int ret;
+
+	mm_segment_t oldfs;
+
+	oldfs = get_fs();
+	set_fs(get_ds());
+	ret = vfs_read(output->mf->mf_filp, aio->io_data, len, &pos);
+	set_fs(oldfs);
+
+	if (unlikely(ret < 0))
+		XIO_ERR("%p %p status=%d\n", output, aio, ret);
+	return ret;
+}
+
+static void sync_file(struct sio_output *output)
+{
+	struct file *file = output->mf->mf_filp;
+	int ret;
+
+#if defined(S_BIAS) || (defined(RHEL_MAJOR) && (RHEL_MAJOR < 7))
+	ret = vfs_fsync(file, file->f_path.dentry, 1);
+#else
+	ret = vfs_fsync(file, 1);
+#endif
+	if (unlikely(ret))
+		XIO_ERR("syncing pages failed: %d\n", ret);
+	goto out_return;
+out_return:;
+}
+
+static
+void _complete(struct sio_output *output, struct aio_object *aio, int err)
+{
+	obj_check(aio);
+
+	if (err < 0) {
+		XIO_ERR(
+		"IO error %d at pos=%lld len=%d (aio=%p io_data=%p)\n",
+		err,
+		aio->io_pos,
+		aio->io_len,
+		aio,
+		aio->io_data);
+	} else {
+		aio_checksum(aio);
+		aio->io_flags |= AIO_UPTODATE;
+	}
+
+#ifdef CONFIG_MARS_DEBUG
+	while (mars_hang_mode & 1)
+		brick_msleep(100);
+#endif
+
+	CHECKED_CALLBACK(aio, err, err_found);
+
+done:
+	sio_io_put(output, aio);
+
+	atomic_dec(&output->work_count);
+	atomic_dec(&xio_global_io_flying);
+	goto out_return;
+err_found:
+	XIO_FAT("giving up...\n");
+	goto done;
+out_return:;
+}
+
+/* This is called by the threads
+ */
+static
+void _sio_io_io(struct sio_threadinfo *tinfo, struct aio_object *aio)
+{
+	struct sio_output *output = tinfo->output;
+	bool barrier = false;
+	int status;
+
+	obj_check(aio);
+
+	atomic_inc(&tinfo->fly_count);
+
+	if (unlikely(!output->mf || !output->mf->mf_filp)) {
+		status = -EINVAL;
+		goto done;
+	}
+
+	if (barrier) {
+		XIO_INF("got barrier request\n");
+		sync_file(output);
+	}
+
+	if (aio->io_rw == READ) {
+		status = read_aops(output, aio);
+	} else {
+		status = write_aops(output, aio);
+		if (barrier || output->brick->o_fdsync)
+			sync_file(output);
+	}
+
+	mapfree_set(output->mf, aio->io_pos, aio->io_pos + aio->io_len);
+
+done:
+	_complete(output, aio, status);
+
+	atomic_dec(&tinfo->fly_count);
+}
+
+/* This is called from outside
+ */
+static
+void sio_io_io(struct sio_output *output, struct aio_object *aio)
+{
+	int index;
+	struct sio_threadinfo *tinfo;
+	struct sio_aio_aspect *aio_a;
+	unsigned long flags;
+
+	obj_check(aio);
+
+	aio_a = sio_aio_get_aspect(output->brick, aio);
+	if (unlikely(!aio_a)) {
+		XIO_FAT("cannot get aspect\n");
+		SIMPLE_CALLBACK(aio, -EINVAL);
+		goto out_return;
+	}
+
+	if (unlikely(!output->brick->power.on_led)) {
+		SIMPLE_CALLBACK(aio, -EBADFD);
+		goto out_return;
+	}
+
+	atomic_inc(&xio_global_io_flying);
+	atomic_inc(&output->work_count);
+	obj_get(aio);
+
+	mapfree_set(output->mf, aio->io_pos, -1);
+
+	index = 0;
+	if (aio->io_rw == READ) {
+		spin_lock_irqsave(&output->g_lock, flags);
+		index = output->index++;
+		spin_unlock_irqrestore(&output->g_lock, flags);
+		index = (index % WITH_THREAD) + 1;
+	}
+
+	tinfo = &output->tinfo[index];
+
+	atomic_inc(&tinfo->total_count);
+	atomic_inc(&tinfo->queue_count);
+
+	spin_lock_irqsave(&tinfo->lock, flags);
+	list_add_tail(&aio_a->io_head, &tinfo->aio_list);
+	spin_unlock_irqrestore(&tinfo->lock, flags);
+
+	wake_up_interruptible(&tinfo->event);
+out_return:;
+}
+
+static int sio_thread(void *data)
+{
+	struct sio_threadinfo *tinfo = data;
+
+	XIO_INF("sio thread has started.\n");
+	/* set_user_nice(current, -20); */
+
+	while (!brick_thread_should_stop()) {
+		struct list_head *tmp = NULL;
+		struct aio_object *aio;
+		struct sio_aio_aspect *aio_a;
+		unsigned long flags;
+
+		wait_event_interruptible_timeout(
+			tinfo->event,
+			!list_empty(&tinfo->aio_list) || brick_thread_should_stop(),
+			HZ);
+
+		tinfo->last_jiffies = jiffies;
+
+		spin_lock_irqsave(&tinfo->lock, flags);
+
+		if (!list_empty(&tinfo->aio_list)) {
+			tmp = tinfo->aio_list.next;
+			list_del_init(tmp);
+			atomic_dec(&tinfo->queue_count);
+		}
+
+		spin_unlock_irqrestore(&tinfo->lock, flags);
+
+		if (!tmp)
+			continue;
+
+		aio_a = container_of(tmp, struct sio_aio_aspect, io_head);
+		aio = aio_a->object;
+		_sio_io_io(tinfo, aio);
+	}
+
+	XIO_INF("sio thread has stopped.\n");
+	return 0;
+}
+
+static int sio_get_info(struct sio_output *output, struct xio_info *info)
+{
+	struct file *file = output->mf->mf_filp;
+
+	if (unlikely(!file || !file->f_mapping || !file->f_mapping->host))
+		return -EINVAL;
+
+	info->tf_align = 1;
+	info->tf_min_size = 1;
+	info->current_size = i_size_read(file->f_mapping->host);
+	XIO_DBG("determined file size = %lld\n", info->current_size);
+	return 0;
+}
+
+/*************** informational * statistics **************/
+
+static noinline
+char *sio_statistics(struct sio_brick *brick, int verbose)
+{
+	struct sio_output *output = brick->outputs[0];
+	char *res = brick_string_alloc(1024);
+	int queue_sum = 0;
+	int fly_sum = 0;
+	int total_sum = 0;
+	int i;
+
+	for (i = 1; i <= WITH_THREAD; i++) {
+		struct sio_threadinfo *tinfo = &output->tinfo[i];
+
+		queue_sum += atomic_read(&tinfo->queue_count);
+		fly_sum += atomic_read(&tinfo->fly_count);
+		total_sum += atomic_read(&tinfo->total_count);
+	}
+
+	snprintf(
+	res, 1024,
+		 "queued read = %d write = %d flying read = %d write = %d total  read = %d write = %d\n",
+		 queue_sum, atomic_read(&output->tinfo[0].queue_count),
+		 fly_sum,   atomic_read(&output->tinfo[0].fly_count),
+		 total_sum, atomic_read(&output->tinfo[0].total_count)
+		);
+	return res;
+}
+
+static noinline
+void sio_reset_statistics(struct sio_brick *brick)
+{
+	struct sio_output *output = brick->outputs[0];
+	int i;
+
+	for (i = 0; i <= WITH_THREAD; i++) {
+		struct sio_threadinfo *tinfo = &output->tinfo[i];
+
+		atomic_set(&tinfo->total_count, 0);
+	}
+}
+
+/*************** object * aspect constructors * destructors **************/
+
+static int sio_aio_aspect_init_fn(struct generic_aspect *_ini)
+{
+	struct sio_aio_aspect *ini = (void *)_ini;
+
+	INIT_LIST_HEAD(&ini->io_head);
+	return 0;
+}
+
+static void sio_aio_aspect_exit_fn(struct generic_aspect *_ini)
+{
+	struct sio_aio_aspect *ini = (void *)_ini;
+
+	(void)ini;
+	CHECK_HEAD_EMPTY(&ini->io_head);
+}
+
+XIO_MAKE_STATICS(sio);
+
+/********************* brick constructors * destructors *******************/
+
+static int sio_brick_construct(struct sio_brick *brick)
+{
+	return 0;
+}
+
+static int sio_switch(struct sio_brick *brick)
+{
+	static int sio_nr;
+	struct sio_output *output = brick->outputs[0];
+	const char *path = output->brick->brick_path;
+	int status = 0;
+
+	if (brick->power.button) {
+		int flags = O_CREAT | O_RDWR | O_LARGEFILE;
+		int index;
+
+		if (brick->power.on_led)
+			goto done;
+
+		if (brick->o_direct) {
+			flags |= O_DIRECT;
+			XIO_INF("using O_DIRECT on %s\n", path);
+		}
+
+		xio_set_power_off_led((void *)brick, false);
+
+		output->mf = mapfree_get(path, flags);
+		if (unlikely(IS_ERR(output->mf))) {
+			XIO_ERR("could not open file = '%s' flags = %d\n", path, flags);
+			status = -ENOENT;
+			goto done;
+		}
+
+		output->index = 0;
+		for (index = 0; index <= WITH_THREAD; index++) {
+			struct sio_threadinfo *tinfo = &output->tinfo[index];
+
+			tinfo->last_jiffies = jiffies;
+			tinfo->thread = brick_thread_create(sio_thread, tinfo, "xio_sio%d", sio_nr++);
+			if (unlikely(!tinfo->thread)) {
+				XIO_ERR("cannot create thread\n");
+				status = -ENOENT;
+				goto done;
+			}
+		}
+		xio_set_power_on_led((void *)brick, true);
+	}
+done:
+	if (unlikely(status < 0) || !brick->power.button) {
+		int index;
+		int count;
+
+		xio_set_power_on_led((void *)brick, false);
+		for (;;) {
+			count = atomic_read(&output->work_count);
+			if (count <= 0)
+				break;
+			XIO_DBG("working on %d requests\n", count);
+			brick_msleep(1000);
+		}
+		for (index = 0; index <= WITH_THREAD; index++) {
+			struct sio_threadinfo *tinfo = &output->tinfo[index];
+
+			if (!tinfo->thread)
+				continue;
+			XIO_DBG("stopping thread %d\n", index);
+			brick_thread_stop(tinfo->thread);
+			tinfo->thread = NULL;
+		}
+		if (output->mf) {
+			XIO_DBG("closing file\n");
+			mapfree_put(output->mf);
+			output->mf = NULL;
+		}
+		xio_set_power_off_led((void *)brick, true);
+	}
+	return status;
+}
+
+static int sio_output_construct(struct sio_output *output)
+{
+	int index;
+
+	spin_lock_init(&output->g_lock);
+	for (index = 0; index <= WITH_THREAD; index++) {
+		struct sio_threadinfo *tinfo = &output->tinfo[index];
+
+		tinfo->output = output;
+		spin_lock_init(&tinfo->lock);
+		init_waitqueue_head(&tinfo->event);
+		INIT_LIST_HEAD(&tinfo->aio_list);
+	}
+
+	return 0;
+}
+
+static int sio_output_destruct(struct sio_output *output)
+{
+	return 0;
+}
+
+/************************ static structs ***********************/
+
+static struct sio_brick_ops sio_brick_ops = {
+	.brick_switch = sio_switch,
+	.brick_statistics = sio_statistics,
+	.reset_statistics = sio_reset_statistics,
+};
+
+static struct sio_output_ops sio_output_ops = {
+	.aio_get = sio_io_get,
+	.aio_put = sio_io_put,
+	.aio_io = sio_io_io,
+	.xio_get_info = sio_get_info,
+};
+
+const struct sio_input_type sio_input_type = {
+	.type_name = "sio_input",
+	.input_size = sizeof(struct sio_input),
+};
+
+static const struct sio_input_type *sio_input_types[] = {
+	&sio_input_type,
+};
+
+const struct sio_output_type sio_output_type = {
+	.type_name = "sio_output",
+	.output_size = sizeof(struct sio_output),
+	.master_ops = &sio_output_ops,
+	.output_construct = &sio_output_construct,
+	.output_destruct = &sio_output_destruct,
+};
+
+static const struct sio_output_type *sio_output_types[] = {
+	&sio_output_type,
+};
+
+const struct sio_brick_type sio_brick_type = {
+	.type_name = "sio_brick",
+	.brick_size = sizeof(struct sio_brick),
+	.max_inputs = 0,
+	.max_outputs = 1,
+	.master_ops = &sio_brick_ops,
+	.aspect_types = sio_aspect_types,
+	.default_input_types = sio_input_types,
+	.default_output_types = sio_output_types,
+	.brick_construct = &sio_brick_construct,
+};
+
+/***************** module init stuff ************************/
+
+int __init init_xio_sio(void)
+{
+	XIO_INF("init_sio()\n");
+	_sio_brick_type = (void *)&sio_brick_type;
+	return sio_register_brick_type();
+}
+
+void exit_xio_sio(void)
+{
+	XIO_INF("exit_sio()\n");
+	sio_unregister_brick_type();
+}
diff --git a/include/linux/xio/xio_sio.h b/include/linux/xio/xio_sio.h
new file mode 100644
index 000000000000..170733f2ea27
--- /dev/null
+++ b/include/linux/xio/xio_sio.h
@@ -0,0 +1,68 @@
+/*
+ * 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_SIO_H
+#define XIO_SIO_H
+
+#include <linux/xio/lib_mapfree.h>
+
+#define WITH_THREAD			16
+
+struct sio_aio_aspect {
+	GENERIC_ASPECT(aio);
+	struct list_head io_head;
+	int alloc_len;
+	bool do_dealloc;
+};
+
+struct sio_brick {
+	XIO_BRICK(sio);
+	/*  parameters */
+	bool o_direct;
+	bool o_fdsync;
+};
+
+struct sio_input {
+	XIO_INPUT(sio);
+};
+
+struct sio_threadinfo {
+	struct sio_output *output;
+	struct list_head aio_list;
+	struct task_struct *thread;
+
+	wait_queue_head_t event;
+	spinlock_t lock;
+	atomic_t queue_count;
+	atomic_t fly_count;
+	atomic_t total_count;
+	unsigned long last_jiffies;
+};
+
+struct sio_output {
+	XIO_OUTPUT(sio);
+	/*  private */
+	struct mapfree_info *mf;
+	struct sio_threadinfo tinfo[WITH_THREAD+1];
+	spinlock_t g_lock;
+	atomic_t work_count;
+	int index;
+};
+
+XIO_TYPES(sio);
+
+#endif
-- 
2.11.0

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