Staging: dst: remove from the tree

DST is dead, no one is using it and upstream
has abandoned it, so remove it from the tree because
it is not going anywhere.
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/Kconfig

@@ -87,8 +87,6 @@ source "drivers/staging/frontier/Kconfig"
 
 source "drivers/staging/dream/Kconfig"
 
-source "drivers/staging/dst/Kconfig"
-
 source "drivers/staging/pohmelfs/Kconfig"
 
 source "drivers/staging/b3dfg/Kconfig"

drivers/staging/Makefile

@@ -26,7 +26,6 @@ obj-$(CONFIG_RTL8192E)		+= rtl8192e/
 obj-$(CONFIG_INPUT_MIMIO)	+= mimio/
 obj-$(CONFIG_TRANZPORT)		+= frontier/
 obj-$(CONFIG_DREAM)		+= dream/
-obj-$(CONFIG_DST)		+= dst/
 obj-$(CONFIG_POHMELFS)		+= pohmelfs/
 obj-$(CONFIG_B3DFG)		+= b3dfg/
 obj-$(CONFIG_IDE_PHISON)	+= phison/

drivers/staging/dst/Kconfig

-config DST
-	tristate "Distributed storage"
-	depends on NET && CRYPTO && SYSFS && BLK_DEV
-	select CONNECTOR
-	---help---
-	DST is a network block device storage, which can be used to organize
-	exported storage on the remote nodes into the local block device.
-
-	DST works on top of any network media and protocol; it is just a matter
-	of configuration utility to understand the correct addresses. The most
-	common example is TCP over IP, which allows to pass through firewalls and
-	create remote backup storage in a different datacenter. DST requires
-	single port to be enabled on the exporting node and outgoing connections
-	on the local node.
-
-	DST works with in-kernel client and server, which improves performance by
-	eliminating unneded data copies and by not depending on the version
-	of the external IO components. It requires userspace configuration utility
-	though.
-
-	DST uses transaction model, when each store has to be explicitly acked
-	from the remote node to be considered as successfully written. There
-	may be lots of in-flight transactions. When remote host does not ack
-	the transaction it will be resent predefined number of times with specified
-	timeouts between them. All those parameters are configurable. Transactions
-	are marked as failed after all resends complete unsuccessfully; having
-	long enough resend timeout and/or large number of resends allows not to
-	return error to the higher (FS usually) layer in case of short network
-	problems or remote node outages. In case of network RAID setup this means
-	that storage will not degrade until transactions are marked as failed, and
-	thus will not force checksum recalculation and data rebuild. In case of
-	connection failure DST will try to reconnect to the remote node automatically.
-	DST sends ping commands at idle time to detect if remote node is alive.
-
-	Because of transactional model it is possible to use zero-copy sending
-	without worry of data corruption (which in turn could be detected by the
-	strong checksums though).
-
-	DST may fully encrypt the data channel in case of untrusted channel and implement
-	strong checksum of the transferred data. It is possible to configure algorithms
-	and crypto keys; they should match on both sides of the network channel.
-	Crypto processing does not introduce noticeble performance overhead, since DST
-	uses configurable pool of threads to perform crypto processing.
-
-	DST utilizes memory pool model of all its transaction allocations (it is the
-	only additional allocation on the client) and server allocations (bio pools,
-	while pages are allocated from the slab).
-
-	At startup DST performs a simple negotiation with the export node to determine
-	access permissions and size of the exported storage. It can be extended if
-	new parameters should be autonegotiated.
-
-	DST carries block IO flags in the protocol, which allows to transparently implement
-	barriers and sync/flush operations. Those flags are used in the export node where
-	IO against the local storage is performed, which means that sync write will be sync
-	on the remote node too, which in turn improves data integrity and improved resistance
-	to errors and data corruption during power outages or storage damages.
-
-	Homepage: http://www.ioremap.net/projects/dst
-	Userspace configuration utility and the latest releases: http://www.ioremap.net/archive/dst/
-
-config DST_DEBUG
-	bool "DST debug"
-	depends on DST
-	---help---
-	This option will enable HEAVY debugging of the DST.
-	Turn it on ONLY if you have to debug some really obscure problem.

drivers/staging/dst/Makefile

-obj-$(CONFIG_DST) += nst.o
-
-nst-y := dcore.o state.o export.o thread_pool.o crypto.o trans.o

drivers/staging/dst/thread_pool.c

-/*
- * 2007+ Copyright (c) Evgeniy Polyakov <zbr@ioremap.net>
- * All rights reserved.
- *
- * 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/dst.h>
-#include <linux/kthread.h>
-#include <linux/slab.h>
-
-/*
- * Thread pool abstraction allows to schedule a work to be performed
- * on behalf of kernel thread. One does not operate with threads itself,
- * instead user provides setup and cleanup callbacks for thread pool itself,
- * and action and cleanup callbacks for each submitted work.
- *
- * Each worker has private data initialized at creation time and data,
- * provided by user at scheduling time.
- *
- * When action is being performed, thread can not be used by other users,
- * instead they will sleep until there is free thread to pick their work.
- */
-struct thread_pool_worker {
-	struct list_head	worker_entry;
-
-	struct task_struct	*thread;
-
-	struct thread_pool	*pool;
-
-	int			error;
-	int			has_data;
-	int			need_exit;
-	unsigned int		id;
-
-	wait_queue_head_t	wait;
-
-	void			*private;
-	void			*schedule_data;
-
-	int			(*action)(void *private, void *schedule_data);
-	void			(*cleanup)(void *private);
-};
-
-static void thread_pool_exit_worker(struct thread_pool_worker *w)
-{
-	kthread_stop(w->thread);
-
-	w->cleanup(w->private);
-	kfree(w);
-}
-
-/*
- * Called to mark thread as ready and allow users to schedule new work.
- */
-static void thread_pool_worker_make_ready(struct thread_pool_worker *w)
-{
-	struct thread_pool *p = w->pool;
-
-	mutex_lock(&p->thread_lock);
-
-	if (!w->need_exit) {
-		list_move_tail(&w->worker_entry, &p->ready_list);
-		w->has_data = 0;
-		mutex_unlock(&p->thread_lock);
-
-		wake_up(&p->wait);
-	} else {
-		p->thread_num--;
-		list_del(&w->worker_entry);
-		mutex_unlock(&p->thread_lock);
-
-		thread_pool_exit_worker(w);
-	}
-}
-
-/*
- * Thread action loop: waits until there is new work.
- */
-static int thread_pool_worker_func(void *data)
-{
-	struct thread_pool_worker *w = data;
-
-	while (!kthread_should_stop()) {
-		wait_event_interruptible(w->wait,
-			kthread_should_stop() || w->has_data);
-
-		if (kthread_should_stop())
-			break;
-
-		if (!w->has_data)
-			continue;
-
-		w->action(w->private, w->schedule_data);
-		thread_pool_worker_make_ready(w);
-	}
-
-	return 0;
-}
-
-/*
- * Remove single worker without specifying which one.
- */
-void thread_pool_del_worker(struct thread_pool *p)
-{
-	struct thread_pool_worker *w = NULL;
-
-	while (!w && p->thread_num) {
-		wait_event(p->wait, !list_empty(&p->ready_list) ||
-				!p->thread_num);
-
-		dprintk("%s: locking list_empty: %d, thread_num: %d.\n",
-				__func__, list_empty(&p->ready_list),
-				p->thread_num);
-
-		mutex_lock(&p->thread_lock);
-		if (!list_empty(&p->ready_list)) {
-			w = list_first_entry(&p->ready_list,
-					struct thread_pool_worker,
-					worker_entry);
-
-			dprintk("%s: deleting w: %p, thread_num: %d, "
-					"list: %p [%p.%p].\n", __func__,
-					w, p->thread_num, &p->ready_list,
-					p->ready_list.prev, p->ready_list.next);
-
-			p->thread_num--;
-			list_del(&w->worker_entry);
-		}
-		mutex_unlock(&p->thread_lock);
-	}
-
-	if (w)
-		thread_pool_exit_worker(w);
-	dprintk("%s: deleted w: %p, thread_num: %d.\n",
-			__func__, w, p->thread_num);
-}
-
-/*
- * Remove a worker with given ID.
- */
-void thread_pool_del_worker_id(struct thread_pool *p, unsigned int id)
-{
-	struct thread_pool_worker *w;
-	int found = 0;
-
-	mutex_lock(&p->thread_lock);
-	list_for_each_entry(w, &p->ready_list, worker_entry) {
-		if (w->id == id) {
-			found = 1;
-			p->thread_num--;
-			list_del(&w->worker_entry);
-			break;
-		}
-	}
-
-	if (!found) {
-		list_for_each_entry(w, &p->active_list, worker_entry) {
-			if (w->id == id) {
-				w->need_exit = 1;
-				break;
-			}
-		}
-	}
-	mutex_unlock(&p->thread_lock);
-
-	if (found)
-		thread_pool_exit_worker(w);
-}
-
-/*
- * Add new worker thread with given parameters.
- * If initialization callback fails, return error.
- */
-int thread_pool_add_worker(struct thread_pool *p,
-		char *name,
-		unsigned int id,
-		void *(*init)(void *private),
-		void (*cleanup)(void *private),
-		void *private)
-{
-	struct thread_pool_worker *w;
-	int err = -ENOMEM;
-
-	w = kzalloc(sizeof(struct thread_pool_worker), GFP_KERNEL);
-	if (!w)
-		goto err_out_exit;
-
-	w->pool = p;
-	init_waitqueue_head(&w->wait);
-	w->cleanup = cleanup;
-	w->id = id;
-
-	w->thread = kthread_run(thread_pool_worker_func, w, "%s", name);
-	if (IS_ERR(w->thread)) {
-		err = PTR_ERR(w->thread);
-		goto err_out_free;
-	}
-
-	w->private = init(private);
-	if (IS_ERR(w->private)) {
-		err = PTR_ERR(w->private);
-		goto err_out_stop_thread;
-	}
-
-	mutex_lock(&p->thread_lock);
-	list_add_tail(&w->worker_entry, &p->ready_list);
-	p->thread_num++;
-	mutex_unlock(&p->thread_lock);
-
-	return 0;
-
-err_out_stop_thread:
-	kthread_stop(w->thread);
-err_out_free:
-	kfree(w);
-err_out_exit:
-	return err;
-}
-
-/*
- * Destroy the whole pool.
- */
-void thread_pool_destroy(struct thread_pool *p)
-{
-	while (p->thread_num) {
-		dprintk("%s: num: %d.\n", __func__, p->thread_num);
-		thread_pool_del_worker(p);
-	}
-
-	kfree(p);
-}
-
-/*
- * Create a pool with given number of threads.
- * They will have sequential IDs started from zero.
- */
-struct thread_pool *thread_pool_create(int num, char *name,
-		void *(*init)(void *private),
-		void (*cleanup)(void *private),
-		void *private)
-{
-	struct thread_pool_worker *w, *tmp;
-	struct thread_pool *p;
-	int err = -ENOMEM;
-	int i;
-
-	p = kzalloc(sizeof(struct thread_pool), GFP_KERNEL);
-	if (!p)
-		goto err_out_exit;
-
-	init_waitqueue_head(&p->wait);
-	mutex_init(&p->thread_lock);
-	INIT_LIST_HEAD(&p->ready_list);
-	INIT_LIST_HEAD(&p->active_list);
-	p->thread_num = 0;
-
-	for (i = 0; i < num; ++i) {
-		err = thread_pool_add_worker(p, name, i, init,
-				cleanup, private);
-		if (err)
-			goto err_out_free_all;
-	}
-
-	return p;
-
-err_out_free_all:
-	list_for_each_entry_safe(w, tmp, &p->ready_list, worker_entry) {
-		list_del(&w->worker_entry);
-		thread_pool_exit_worker(w);
-	}
-	kfree(p);
-err_out_exit:
-	return ERR_PTR(err);
-}
-
-/*
- * Schedule execution of the action on a given thread,
- * provided ID pointer has to match previously stored
- * private data.
- */
-int thread_pool_schedule_private(struct thread_pool *p,
-		int (*setup)(void *private, void *data),
-		int (*action)(void *private, void *data),
-		void *data, long timeout, void *id)
-{
-	struct thread_pool_worker *w, *tmp, *worker = NULL;
-	int err = 0;
-
-	while (!worker && !err) {
-		timeout = wait_event_interruptible_timeout(p->wait,
-				!list_empty(&p->ready_list),
-				timeout);
-
-		if (!timeout) {
-			err = -ETIMEDOUT;
-			break;
-		}
-
-		worker = NULL;
-		mutex_lock(&p->thread_lock);
-		list_for_each_entry_safe(w, tmp, &p->ready_list, worker_entry) {
-			if (id && id != w->private)
-				continue;
-
-			worker = w;
-
-			list_move_tail(&w->worker_entry, &p->active_list);
-
-			err = setup(w->private, data);
-			if (!err) {
-				w->schedule_data = data;
-				w->action = action;
-				w->has_data = 1;
-				wake_up(&w->wait);
-			} else {
-				list_move_tail(&w->worker_entry,
-						&p->ready_list);
-			}
-
-			break;
-		}
-		mutex_unlock(&p->thread_lock);
-	}
-
-	return err;
-}
-
-/*
- * Schedule execution on arbitrary thread from the pool.
- */
-int thread_pool_schedule(struct thread_pool *p,
-		int (*setup)(void *private, void *data),
-		int (*action)(void *private, void *data),
-		void *data, long timeout)
-{
-	return thread_pool_schedule_private(p, setup,
-			action, data, timeout, NULL);
-}

drivers/staging/dst/trans.c

-/*
- * 2007+ Copyright (c) Evgeniy Polyakov <zbr@ioremap.net>
- * All rights reserved.
- *
- * 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/bio.h>
-#include <linux/dst.h>
-#include <linux/slab.h>
-#include <linux/mempool.h>
-
-/*
- * Transaction memory pool size.
- */
-static int dst_mempool_num = 32;
-module_param(dst_mempool_num, int, 0644);
-
-/*
- * Transaction tree management.
- */
-static inline int dst_trans_cmp(dst_gen_t gen, dst_gen_t new)
-{
-	if (gen < new)
-		return 1;
-	if (gen > new)
-		return -1;
-	return 0;
-}
-
-struct dst_trans *dst_trans_search(struct dst_node *node, dst_gen_t gen)
-{
-	struct rb_root *root = &node->trans_root;
-	struct rb_node *n = root->rb_node;
-	struct dst_trans *t, *ret = NULL;
-	int cmp;
-
-	while (n) {
-		t = rb_entry(n, struct dst_trans, trans_entry);
-
-		cmp = dst_trans_cmp(t->gen, gen);
-		if (cmp < 0)
-			n = n->rb_left;
-		else if (cmp > 0)
-			n = n->rb_right;
-		else {
-			ret = t;
-			break;
-		}
-	}
-
-	dprintk("%s: %s transaction: id: %llu.\n", __func__,
-			(ret) ? "found" : "not found", gen);
-
-	return ret;
-}
-
-static int dst_trans_insert(struct dst_trans *new)
-{
-	struct rb_root *root = &new->n->trans_root;
-	struct rb_node **n = &root->rb_node, *parent = NULL;
-	struct dst_trans *ret = NULL, *t;
-	int cmp;
-
-	while (*n) {
-		parent = *n;
-
-		t = rb_entry(parent, struct dst_trans, trans_entry);
-
-		cmp = dst_trans_cmp(t->gen, new->gen);
-		if (cmp < 0)
-			n = &parent->rb_left;
-		else if (cmp > 0)
-			n = &parent->rb_right;
-		else {
-			ret = t;
-			break;
-		}
-	}
-
-	new->send_time = jiffies;
-	if (ret) {
-		printk(KERN_DEBUG "%s: exist: old: gen: %llu, bio: %llu/%u, "
-			"send_time: %lu, new: gen: %llu, bio: %llu/%u, "
-			"send_time: %lu.\n", __func__,
-			ret->gen, (u64)ret->bio->bi_sector,
-			ret->bio->bi_size, ret->send_time,
-			new->gen, (u64)new->bio->bi_sector,
-			new->bio->bi_size, new->send_time);
-		return -EEXIST;
-	}
-
-	rb_link_node(&new->trans_entry, parent, n);
-	rb_insert_color(&new->trans_entry, root);
-
-	dprintk("%s: inserted: gen: %llu, bio: %llu/%u, send_time: %lu.\n",
-		__func__, new->gen, (u64)new->bio->bi_sector,
-		new->bio->bi_size, new->send_time);
-
-	return 0;
-}
-
-int dst_trans_remove_nolock(struct dst_trans *t)
-{
-	struct dst_node *n = t->n;
-
-	if (t->trans_entry.rb_parent_color) {
-		rb_erase(&t->trans_entry, &n->trans_root);
-		t->trans_entry.rb_parent_color = 0;
-	}
-	return 0;
-}
-
-int dst_trans_remove(struct dst_trans *t)
-{
-	int ret;
-	struct dst_node *n = t->n;
-
-	mutex_lock(&n->trans_lock);
-	ret = dst_trans_remove_nolock(t);
-	mutex_unlock(&n->trans_lock);
-
-	return ret;
-}
-
-/*
- * When transaction is completed and there are no more users,
- * we complete appriate block IO request with given error status.
- */
-void dst_trans_put(struct dst_trans *t)
-{
-	if (atomic_dec_and_test(&t->refcnt)) {
-		struct bio *bio = t->bio;
-
-		dprintk("%s: completed t: %p, gen: %llu, bio: %p.\n",
-				__func__, t, t->gen, bio);
-
-		bio_endio(bio, t->error);
-		bio_put(bio);
-
-		dst_node_put(t->n);
-		mempool_free(t, t->n->trans_pool);
-	}
-}
-
-/*
- * Process given block IO request: allocate transaction, insert it into the tree
- * and send/schedule crypto processing.
- */
-int dst_process_bio(struct dst_node *n, struct bio *bio)
-{
-	struct dst_trans *t;
-	int err = -ENOMEM;
-
-	t = mempool_alloc(n->trans_pool, GFP_NOFS);
-	if (!t)
-		goto err_out_exit;
-
-	t->n = dst_node_get(n);
-	t->bio = bio;
-	t->error = 0;
-	t->retries = 0;
-	atomic_set(&t->refcnt, 1);
-	t->gen = atomic_long_inc_return(&n->gen);
-
-	t->enc = bio_data_dir(bio);
-	dst_bio_to_cmd(bio, &t->cmd, DST_IO, t->gen);
-
-	mutex_lock(&n->trans_lock);
-	err = dst_trans_insert(t);
-	mutex_unlock(&n->trans_lock);
-	if (err)
-		goto err_out_free;
-
-	dprintk("%s: gen: %llu, bio: %llu/%u, dir/enc: %d, need_crypto: %d.\n",
-			__func__, t->gen, (u64)bio->bi_sector,
-			bio->bi_size, t->enc, dst_need_crypto(n));
-
-	if (dst_need_crypto(n) && t->enc)
-		dst_trans_crypto(t);
-	else
-		dst_trans_send(t);
-
-	return 0;
-
-err_out_free:
-	dst_node_put(n);
-	mempool_free(t, n->trans_pool);
-err_out_exit:
-	bio_endio(bio, err);
-	bio_put(bio);
-	return err;
-}
-
-/*
- * Scan for timeout/stale transactions.
- * Each transaction is being resent multiple times before error completion.
- */
-static void dst_trans_scan(struct work_struct *work)
-{
-	struct dst_node *n = container_of(work, struct dst_node,
-			trans_work.work);
-	struct rb_node *rb_node;
-	struct dst_trans *t;
-	unsigned long timeout = n->trans_scan_timeout;
-	int num = 10 * n->trans_max_retries;
-
-	mutex_lock(&n->trans_lock);
-
-	for (rb_node = rb_first(&n->trans_root); rb_node; ) {
-		t = rb_entry(rb_node, struct dst_trans, trans_entry);
-
-		if (timeout && time_after(t->send_time + timeout, jiffies)
-				&& t->retries == 0)
-			break;
-#if 0
-		dprintk("%s: t: %p, gen: %llu, n: %s, retries: %u, max: %u.\n",
-			__func__, t, t->gen, n->name,
-			t->retries, n->trans_max_retries);
-#endif
-		if (--num == 0)
-			break;
-
-		dst_trans_get(t);
-
-		rb_node = rb_next(rb_node);
-
-		if (timeout && (++t->retries < n->trans_max_retries)) {
-			dst_trans_send(t);
-		} else {
-			t->error = -ETIMEDOUT;
-			dst_trans_remove_nolock(t);
-			dst_trans_put(t);
-		}
-
-		dst_trans_put(t);
-	}
-
-	mutex_unlock(&n->trans_lock);
-
-	/*
-	 * If no timeout specified then system is in the middle of exiting
-	 * process, so no need to reschedule scanning process again.
-	 */
-	if (timeout) {
-		if (!num)
-			timeout = HZ;
-		schedule_delayed_work(&n->trans_work, timeout);
-	}
-}
-
-/*
- * Flush all transactions and mark them as timed out.
- * Destroy transaction pools.
- */
-void dst_node_trans_exit(struct dst_node *n)
-{
-	struct dst_trans *t;
-	struct rb_node *rb_node;
-
-	if (!n->trans_cache)
-		return;
-
-	dprintk("%s: n: %p, cancelling the work.\n", __func__, n);
-	cancel_delayed_work_sync(&n->trans_work);
-	flush_scheduled_work();
-	dprintk("%s: n: %p, work has been cancelled.\n", __func__, n);
-
-	for (rb_node = rb_first(&n->trans_root); rb_node; ) {
-		t = rb_entry(rb_node, struct dst_trans, trans_entry);
-
-		dprintk("%s: t: %p, gen: %llu, n: %s.\n",
-			__func__, t, t->gen, n->name);
-
-		rb_node = rb_next(rb_node);
-
-		t->error = -ETIMEDOUT;
-		dst_trans_remove_nolock(t);
-		dst_trans_put(t);
-	}
-
-	mempool_destroy(n->trans_pool);
-	kmem_cache_destroy(n->trans_cache);
-}
-
-/*
- * Initialize transaction storage for given node.
- * Transaction stores not only control information,
- * but also network command and crypto data (if needed)
- * to reduce number of allocations. Thus transaction size
- * differs from node to node.
- */
-int dst_node_trans_init(struct dst_node *n, unsigned int size)
-{
-	/*
-	 * We need this, since node with given name can be dropped from the
-	 * hash table, but be still alive, so subsequent creation of the node
-	 * with the same name may collide with existing cache name.
-	 */
-
-	snprintf(n->cache_name, sizeof(n->cache_name), "%s-%p", n->name, n);
-
-	n->trans_cache = kmem_cache_create(n->cache_name,
-			size + n->crypto.crypto_attached_size,
-			0, 0, NULL);
-	if (!n->trans_cache)
-		goto err_out_exit;
-
-	n->trans_pool = mempool_create_slab_pool(dst_mempool_num,
-			n->trans_cache);
-	if (!n->trans_pool)
-		goto err_out_cache_destroy;
-
-	mutex_init(&n->trans_lock);
-	n->trans_root = RB_ROOT;
-
-	INIT_DELAYED_WORK(&n->trans_work, dst_trans_scan);
-	schedule_delayed_work(&n->trans_work, n->trans_scan_timeout);
-
-	dprintk("%s: n: %p, size: %u, crypto: %u.\n",
-		__func__, n, size, n->crypto.crypto_attached_size);
-
-	return 0;
-
-err_out_cache_destroy:
-	kmem_cache_destroy(n->trans_cache);
-err_out_exit:
-	return -ENOMEM;
-}