Module Name:    src
Committed By:   tkusumi
Date:           Sun Jan  5 08:08:26 UTC 2020

Modified Files:
        src/sys/dev/dm: dm.h dm_target.c
Added Files:
        src/sys/dev/dm: dm_target_delay.c

Log Message:
dm: Add dm-delay target

Ported from DragonFlyBSD, but this target had originally existed in
Linux kernel. See below for details.
https://www.kernel.org/doc/Documentation/device-mapper/delay.txt

Due to "tick" in hz(9) not working (which results in dmdlthread spinning
forever in _submit_queue() without dp extracted from delayed list
and queued into submit list), this hasn't been hooked to dm.kmod yet.

taken-from: DragonFlyBSD


To generate a diff of this commit:
cvs rdiff -u -r1.53 -r1.54 src/sys/dev/dm/dm.h
cvs rdiff -u -r1.38 -r1.39 src/sys/dev/dm/dm_target.c
cvs rdiff -u -r0 -r1.1 src/sys/dev/dm/dm_target_delay.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.

Modified files:

Index: src/sys/dev/dm/dm.h
diff -u src/sys/dev/dm/dm.h:1.53 src/sys/dev/dm/dm.h:1.54
--- src/sys/dev/dm/dm.h:1.53	Thu Jan  2 06:22:23 2020
+++ src/sys/dev/dm/dm.h	Sun Jan  5 08:08:26 2020
@@ -1,4 +1,4 @@
-/*        $NetBSD: dm.h,v 1.53 2020/01/02 06:22:23 tkusumi Exp $      */
+/*        $NetBSD: dm.h,v 1.54 2020/01/05 08:08:26 tkusumi Exp $      */
 
 /*
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -273,6 +273,18 @@ int dm_target_zero_destroy(dm_table_entr
 int dm_target_zero_upcall(dm_table_entry_t *, struct buf *);
 
 #if 0
+/* dm_target_delay.c */
+void dm_target_delay_pool_create(void);
+void dm_target_delay_pool_destroy(void);
+int dm_target_delay_init(dm_table_entry_t *, int, char **);
+char *dm_target_delay_info(void *);
+char *dm_target_delay_table(void *);
+int dm_target_delay_strategy(dm_table_entry_t *, struct buf *);
+int dm_target_delay_sync(dm_table_entry_t *);
+int dm_target_delay_destroy(dm_table_entry_t *);
+int dm_target_delay_upcall(dm_table_entry_t *, struct buf *);
+int dm_target_delay_secsize(dm_table_entry_t *, unsigned int *);
+
 /* dm_target_flakey.c */
 int dm_target_flakey_init(dm_table_entry_t *, int, char **);
 char *dm_target_flakey_table(void *);

Index: src/sys/dev/dm/dm_target.c
diff -u src/sys/dev/dm/dm_target.c:1.38 src/sys/dev/dm/dm_target.c:1.39
--- src/sys/dev/dm/dm_target.c:1.38	Thu Jan  2 06:22:23 2020
+++ src/sys/dev/dm/dm_target.c	Sun Jan  5 08:08:26 2020
@@ -1,4 +1,4 @@
-/*        $NetBSD: dm_target.c,v 1.38 2020/01/02 06:22:23 tkusumi Exp $      */
+/*        $NetBSD: dm_target.c,v 1.39 2020/01/05 08:08:26 tkusumi Exp $      */
 
 /*
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -29,7 +29,7 @@
  * POSSIBILITY OF SUCH DAMAGE.
  */
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: dm_target.c,v 1.38 2020/01/02 06:22:23 tkusumi Exp $");
+__KERNEL_RCSID(0, "$NetBSD: dm_target.c,v 1.39 2020/01/05 08:08:26 tkusumi Exp $");
 
 #include <sys/types.h>
 #include <sys/param.h>
@@ -238,7 +238,10 @@ dm_target_destroy(void)
 	mutex_exit(&dm_target_mutex);
 
 	mutex_destroy(&dm_target_mutex);
-
+#if 0
+	/* Target specific module destroy routine. */
+	dm_target_delay_pool_destroy();
+#endif
 	return 0;
 }
 
@@ -359,6 +362,22 @@ dm_target_init(void)
 	if (dm_target_insert(dmt))
 		printf("Failed to insert zero\n");
 #if 0
+	dmt = dm_target_alloc("delay");
+	dmt->version[0] = 1;
+	dmt->version[1] = 0;
+	dmt->version[2] = 0;
+	dmt->init = &dm_target_delay_init;
+	dmt->info = &dm_target_delay_info;
+	dmt->table = &dm_target_delay_table;
+	dmt->strategy = &dm_target_delay_strategy;
+	dmt->sync = &dm_target_delay_sync;
+	dmt->destroy = &dm_target_delay_destroy;
+	dmt->upcall = &dm_target_delay_upcall;
+	dmt->secsize = &dm_target_delay_secsize;
+	if (dm_target_insert(dmt))
+		printf("Failed to insert delay\n");
+	dm_target_delay_pool_create();
+
 	dmt = dm_target_alloc("flakey");
 	dmt->version[0] = 1;
 	dmt->version[1] = 0;

Added files:

Index: src/sys/dev/dm/dm_target_delay.c
diff -u /dev/null src/sys/dev/dm/dm_target_delay.c:1.1
--- /dev/null	Sun Jan  5 08:08:26 2020
+++ src/sys/dev/dm/dm_target_delay.c	Sun Jan  5 08:08:26 2020
@@ -0,0 +1,513 @@
+/*        $NetBSD: dm_target_delay.c,v 1.1 2020/01/05 08:08:26 tkusumi Exp $      */
+
+/*
+ * Copyright (c) 2020 The NetBSD Foundation, Inc.
+ * Copyright (c) 2015 The DragonFly Project.  All rights reserved.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to The NetBSD Foundation
+ * by Tomohiro Kusumi <tkus...@netbsd.org>.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
+ * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+ * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+#include <sys/cdefs.h>
+__KERNEL_RCSID(0, "$NetBSD: dm_target_delay.c,v 1.1 2020/01/05 08:08:26 tkusumi Exp $");
+
+#include <sys/types.h>
+#include <sys/param.h>
+#include <sys/kernel.h>
+#include <sys/buf.h>
+#include <sys/kmem.h>
+#include <sys/mutex.h>
+#include <sys/queue.h>
+#include <sys/callout.h>
+#include <sys/pool.h>
+#include <sys/kthread.h>
+
+#include "dm.h"
+
+struct dm_delay_buf {
+	TAILQ_ENTRY(dm_delay_buf) entry;
+	struct buf *bp;
+	int expire;
+};
+TAILQ_HEAD(dm_delay_buf_list, dm_delay_buf);
+
+struct dm_delay_info {
+	dm_pdev_t *pdev;
+	uint64_t offset;
+	int delay;
+	int count;
+	int enabled;
+	struct dm_delay_buf_list buf_list;
+	struct callout cal;
+	kmutex_t buf_mtx;
+	kmutex_t cal_mtx;
+	kmutex_t token; /* lwkt_token in DragonFly */
+};
+
+typedef struct target_delay_config {
+	struct dm_delay_info read;
+	struct dm_delay_info write;
+	int argc; /* either 3 or 6 */
+} dm_target_delay_config_t;
+
+static int _init(struct dm_delay_info*, char**);
+static int _table(struct dm_delay_info*, char*);
+static void _strategy(struct dm_delay_info*, struct buf*);
+static __inline void _submit(struct dm_delay_info*, struct buf*);
+static void _destroy(struct dm_delay_info*);
+static void _timeout(void*);
+static void _thread(void*);
+static __inline void _debug(struct dm_delay_info*, const char*);
+
+static struct pool pool;
+static bool pool_initialized = false;
+
+#ifdef DM_TARGET_MODULE
+/*
+ * Every target can be compiled directly to dm driver or as a
+ * separate module this part of target is used for loading targets
+ * to dm driver.
+ * Target can be unloaded from kernel only if there are no users of
+ * it e.g. there are no devices which uses that target.
+ */
+#include <sys/kernel.h>
+#include <sys/module.h>
+
+MODULE(MODULE_CLASS_MISC, dm_target_delay, NULL);
+
+static int
+dm_target_delay_modcmd(modcmd_t cmd, void *arg)
+{
+	dm_target_t *dmt;
+	int r;
+
+	switch (cmd) {
+	case MODULE_CMD_INIT:
+		if ((dmt = dm_target_lookup("delay")) != NULL) {
+			dm_target_unbusy(dmt);
+			return EEXIST;
+		}
+		dmt = dm_target_alloc("delay");
+
+		dmt->version[0] = 1;
+		dmt->version[1] = 0;
+		dmt->version[2] = 0;
+		dmt->init = &dm_target_delay_init;
+		dmt->table = &dm_target_delay_table;
+		dmt->strategy = &dm_target_delay_strategy;
+		dmt->sync = &dm_target_delay_sync;
+		dmt->destroy = &dm_target_delay_destroy;
+		dmt->upcall = &dm_target_delay_upcall;
+		dmt->secsize = &dm_target_delay_secsize;
+
+		dm_target_delay_pool_create();
+		r = dm_target_insert(dmt);
+
+		break;
+
+	case MODULE_CMD_FINI:
+		r = dm_target_rem("delay");
+		dm_target_delay_pool_destroy();
+		break;
+
+	case MODULE_CMD_STAT:
+		return ENOTTY;
+
+	default:
+		return ENOTTY;
+	}
+
+	return r;
+}
+#endif
+
+int
+dm_target_delay_init(dm_table_entry_t *table_en, int argc, char **argv)
+{
+	dm_target_delay_config_t *tdc;
+	int ret;
+
+	if (argc != 3 && argc != 6) {
+		printf("Delay target takes 3 or 6 args, %d given\n", argc);
+		return EINVAL;
+	}
+
+	aprint_debug("Delay target init function called: argc=%d\n", argc);
+
+	tdc = kmem_alloc(sizeof(dm_target_delay_config_t), KM_SLEEP);
+	tdc->argc = argc;
+
+	ret = _init(&tdc->read, argv);
+	if (ret) {
+		kmem_free(tdc, sizeof(*tdc));
+		return ret;
+	}
+
+	if (argc == 6)
+		argv += 3;
+
+	ret = _init(&tdc->write, argv);
+	if (ret) {
+		dm_pdev_decr(tdc->read.pdev);
+		kmem_free(tdc, sizeof(*tdc));
+		return ret;
+	}
+
+	dm_table_add_deps(table_en, tdc->read.pdev);
+	dm_table_add_deps(table_en, tdc->write.pdev);
+
+	table_en->target_config = tdc;
+
+	return 0;
+}
+
+static int
+_init(struct dm_delay_info *di, char **argv)
+{
+	dm_pdev_t *dmp;
+	int tmp;
+
+	if (argv[0] == NULL)
+		return EINVAL;
+	if ((dmp = dm_pdev_insert(argv[0])) == NULL)
+		return ENOENT;
+
+	di->pdev = dmp;
+	di->offset = atoi64(argv[1]);
+	tmp = atoi64(argv[2]);
+	di->delay = tmp * hz / 1000;
+	di->count = 0;
+
+	TAILQ_INIT(&di->buf_list);
+	callout_init(&di->cal, 0);
+	mutex_init(&di->buf_mtx, MUTEX_DEFAULT, IPL_NONE);
+	mutex_init(&di->cal_mtx, MUTEX_DEFAULT, IPL_NONE);
+	mutex_init(&di->token, MUTEX_DEFAULT, IPL_NONE);
+
+	di->enabled = 1;
+	if (kthread_create(PRI_NONE, 0, NULL, _thread, di, NULL,
+	    "dmdlthread")) {
+		printf("Failed to create delay target's kthread\n");
+		/* XXX cleanup ? */
+		return EINVAL;
+	}
+
+	_debug(di, "init");
+	return 0;
+}
+
+char *
+dm_target_delay_info(void *target_config)
+{
+	dm_target_delay_config_t *tdc;
+	char *params;
+
+	tdc = target_config;
+	KASSERT(tdc != NULL);
+
+	aprint_debug("Delay target info function called\n");
+
+	params = kmem_alloc(DM_MAX_PARAMS_SIZE, KM_SLEEP);
+	snprintf(params, DM_MAX_PARAMS_SIZE, "%d %d", tdc->read.count,
+	    tdc->write.count);
+
+	return params;
+}
+
+char *
+dm_target_delay_table(void *target_config)
+{
+	dm_target_delay_config_t *tdc;
+	char *params, *p;
+
+	tdc = target_config;
+	KASSERT(tdc != NULL);
+
+	aprint_debug("Delay target table function called\n");
+
+	params = kmem_alloc(DM_MAX_PARAMS_SIZE, KM_SLEEP);
+	p = params;
+	p += _table(&tdc->read, p);
+	if (tdc->argc == 6) {
+		p += snprintf(p, DM_MAX_PARAMS_SIZE, " ");
+		_table(&tdc->write, p);
+	}
+
+	return params;
+}
+
+static int
+_table(struct dm_delay_info *di, char *p)
+{
+
+	return snprintf(p, DM_MAX_PARAMS_SIZE, "%s %" PRIu64 " %d",
+	    di->pdev->udev_name, di->offset, di->delay);
+}
+
+int
+dm_target_delay_strategy(dm_table_entry_t *table_en, struct buf *bp)
+{
+	dm_target_delay_config_t *tdc;
+	struct dm_delay_info *di;
+
+	tdc = table_en->target_config;
+	KASSERT(tdc != NULL);
+
+	if (bp->b_flags & B_READ)
+		di = &tdc->read;
+	else
+		di = &tdc->write;
+
+	if (di) {
+		if (di->delay) {
+			_strategy(di, bp);
+		} else {
+			_submit(di, bp);
+		}
+	} else {
+		struct vnode *vnode = tdc->write.pdev->pdev_vnode;
+		KASSERT(0);
+		VOP_STRATEGY(vnode, bp);
+	}
+
+	return 0;
+}
+
+static void
+_strategy(struct dm_delay_info *di, struct buf *bp)
+{
+	struct dm_delay_buf *dp;
+
+	dp = pool_get(&pool, PR_WAITOK);
+	dp->bp = bp;
+	dp->expire = tick + di->delay;
+
+	mutex_enter(&di->buf_mtx);
+	di->count++;
+	TAILQ_INSERT_TAIL(&di->buf_list, dp, entry);
+	mutex_exit(&di->buf_mtx);
+
+	mutex_enter(&di->cal_mtx);
+	if (!callout_pending(&di->cal))
+		callout_reset(&di->cal, di->delay, _timeout, di);
+	mutex_exit(&di->cal_mtx);
+}
+
+static __inline void
+_submit(struct dm_delay_info *di, struct buf *bp)
+{
+
+	_debug(di, "submit");
+
+	bp->b_blkno += di->offset;
+	VOP_STRATEGY(di->pdev->pdev_vnode, bp);
+}
+
+static void
+_submit_queue(struct dm_delay_info *di, int submit_all)
+{
+	struct dm_delay_buf *dp;
+	struct dm_delay_buf_list tmp_list;
+	int next = -1;
+	int reset = 0;
+
+	_debug(di, "submitq");
+	TAILQ_INIT(&tmp_list);
+
+	mutex_enter(&di->buf_mtx);
+	while ((dp = TAILQ_FIRST(&di->buf_list)) != NULL) {
+		if (submit_all || tick > dp->expire) {
+			TAILQ_REMOVE(&di->buf_list, dp, entry);
+			TAILQ_INSERT_TAIL(&tmp_list, dp, entry);
+			di->count--;
+			continue;
+		}
+		if (reset == 0) {
+			reset = 1;
+			next = dp->expire;
+		} else {
+			next = lmin(next, dp->expire);
+		}
+	}
+	mutex_exit(&di->buf_mtx);
+
+	if (reset) {
+		mutex_enter(&di->cal_mtx);
+		callout_reset(&di->cal, next - tick, _timeout, di);
+		mutex_exit(&di->cal_mtx);
+	}
+
+	while ((dp = TAILQ_FIRST(&tmp_list)) != NULL) {
+		TAILQ_REMOVE(&tmp_list, dp, entry);
+		_submit(di, dp->bp);
+		pool_put(&pool, dp);
+	}
+}
+
+int
+dm_target_delay_sync(dm_table_entry_t *table_en)
+{
+	dm_target_delay_config_t *tdc;
+	int cmd;
+
+	tdc = table_en->target_config;
+	cmd = 1;
+
+	return VOP_IOCTL(tdc->write.pdev->pdev_vnode, DIOCCACHESYNC, &cmd,
+	    FREAD | FWRITE, kauth_cred_get());
+}
+
+int
+dm_target_delay_destroy(dm_table_entry_t *table_en)
+{
+	dm_target_delay_config_t *tdc;
+
+	tdc = table_en->target_config;
+	if (tdc == NULL)
+		goto out;
+
+	_destroy(&tdc->read);
+	_destroy(&tdc->write);
+
+	kmem_free(tdc, sizeof(*tdc));
+out:
+	/* Unbusy target so we can unload it */
+	dm_target_unbusy(table_en->target);
+
+	return 0;
+}
+
+static void
+_destroy(struct dm_delay_info *di)
+{
+
+	_debug(di, "destroy");
+
+	mutex_enter(&di->token);
+	di->enabled = 0;
+
+	mutex_enter(&di->cal_mtx);
+	if (callout_pending(&di->cal))
+		callout_halt(&di->cal, NULL);
+	mutex_exit(&di->cal_mtx);
+
+	_submit_queue(di, 1);
+	mutex_exit(&di->token);
+	wakeup(di);
+	/* XXX race here (DragonFly uses lwkt_token instead of mutex) */
+	tsleep(&di->enabled, 0, "dmdldestroy", 0);
+
+	mutex_destroy(&di->token);
+	mutex_destroy(&di->cal_mtx);
+	mutex_destroy(&di->buf_mtx);
+
+	dm_pdev_decr(di->pdev);
+}
+
+int
+dm_target_delay_upcall(dm_table_entry_t *table_en, struct buf *bp)
+{
+
+	return 0;
+}
+
+int
+dm_target_delay_secsize(dm_table_entry_t *table_en, unsigned int *secsizep)
+{
+	dm_target_delay_config_t *tdc;
+	unsigned int secsize;
+
+	secsize = 0;
+
+	tdc = table_en->target_config;
+	if (tdc != NULL)
+		secsize = tdc->write.pdev->pdev_secsize;
+
+	*secsizep = secsize;
+
+	return 0;
+}
+
+static void
+_timeout(void *arg)
+{
+	struct dm_delay_info *di = arg;
+
+	_debug(di, "timeout");
+	wakeup(di);
+}
+
+static void
+_thread(void *arg)
+{
+	struct dm_delay_info *di = arg;
+
+	_debug(di, "thread init");
+	mutex_enter(&di->token);
+
+	while (di->enabled) {
+		mutex_exit(&di->token);
+		tsleep(di, 0, "dmdlthread", 0);
+		_submit_queue(di, 0);
+		mutex_enter(&di->token);
+	}
+
+	mutex_exit(&di->token);
+	wakeup(&di->enabled);
+
+	_debug(di, "thread exit");
+	kthread_exit(0);
+}
+
+static __inline void
+_debug(struct dm_delay_info *di, const char *msg)
+{
+
+	aprint_debug("%-8s: %d pdev=%s offset=%ju delay=%d count=%d\n",
+	    msg, di->enabled, di->pdev->name, (uintmax_t)di->offset, di->delay,
+	    di->count);
+}
+
+void
+dm_target_delay_pool_create(void)
+{
+
+	if (!pool_initialized) {
+		pool_init(&pool, sizeof(struct dm_delay_buf), 0, 0, 0,
+		    "dmdlobj", &pool_allocator_nointr, IPL_NONE);
+		pool_initialized = true;
+		aprint_debug("Delay target pool initialized\n");
+	}
+}
+
+void
+dm_target_delay_pool_destroy(void)
+{
+
+	if (pool_initialized) {
+		pool_destroy(&pool);
+		pool_initialized = false;
+		aprint_debug("Delay target pool destroyed\n");
+	}
+}

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