diff options
Diffstat (limited to 'sys/dev/dm/dm_table.c')
| -rw-r--r-- | sys/dev/dm/dm_table.c | 273 |
1 files changed, 273 insertions, 0 deletions
diff --git a/sys/dev/dm/dm_table.c b/sys/dev/dm/dm_table.c new file mode 100644 index 00000000000..a20897a367c --- /dev/null +++ b/sys/dev/dm/dm_table.c @@ -0,0 +1,273 @@ +/* $NetBSD: dm_table.c,v 1.2 2008/12/19 15:24:03 haad Exp $ */ + +/* + * Copyright (c) 2008 The NetBSD Foundation, Inc. + * All rights reserved. + * + * This code is derived from software contributed to The NetBSD Foundation + * by Adam Hamsik. + * + * 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/types.h> +#include <sys/param.h> + +#include <sys/kmem.h> + +#include "dm.h" + +/* + * There are two types of users of this interface: + * + * a) Readers such as + * dmstrategy, dmgetdisklabel, dmsize, dm_dev_status_ioctl, + * dm_table_deps_ioctl, dm_table_status_ioctl, dm_table_reload_ioctl + * + * b) Writers such as + * dm_dev_remove_ioctl, dm_dev_resume_ioctl, dm_table_clear_ioctl + * + * Writers can work with table_head only when there are no readers. I + * use reference counting on io_cnt. + * + */ + +static int dm_table_busy(dm_table_head_t *, uint8_t ); +static void dm_table_unbusy(dm_table_head_t *); + +/* + * Function to increment table user reference counter. Return id + * of table_id table. + * DM_TABLE_ACTIVE will return active table id. + * DM_TABLE_INACTIVE will return inactive table id. + */ +static int +dm_table_busy(dm_table_head_t *head, uint8_t table_id) +{ + uint8_t id; + + id = 0; + + mutex_enter(&head->table_mtx); + + if (table_id == DM_TABLE_ACTIVE) + id = head->cur_active_table; + else + id = 1 - head->cur_active_table; + + head->io_cnt++; + + mutex_exit(&head->table_mtx); + return id; +} + +/* + * Function release table lock and eventually wakeup all waiters. + */ +static void +dm_table_unbusy(dm_table_head_t *head) +{ + KASSERT(head->io_cnt != 0); + + mutex_enter(&head->table_mtx); + + if (--head->io_cnt == 0) + cv_broadcast(&head->table_cv); + + mutex_exit(&head->table_mtx); +} + +/* + * Return current active table to caller, increment io_cnt reference counter. + */ +dm_table_t * +dm_table_get_entry(dm_table_head_t *head, uint8_t table_id) +{ + uint8_t id; + + id = dm_table_busy(head, table_id); + + return &head->tables[id]; +} + +/* + * Decrement io reference counter and wake up all callers, with table_head cv. + */ +void +dm_table_release(dm_table_head_t *head, uint8_t table_id) +{ + dm_table_unbusy(head); +} + +/* + * Switch table from inactive to active mode. Have to wait until io_cnt is 0. + */ +void +dm_table_switch_tables(dm_table_head_t *head) +{ + mutex_enter(&head->table_mtx); + + while (head->io_cnt != 0) + cv_wait(&head->table_cv, &head->table_mtx); + + head->cur_active_table = 1 - head->cur_active_table; + + mutex_exit(&head->table_mtx); +} + +/* + * Destroy all table data. This function can run when there are no + * readers on table lists. + * + * XXX Is it ok to call kmem_free and potentialy VOP_CLOSE with held mutex ?xs + */ +int +dm_table_destroy(dm_table_head_t *head, uint8_t table_id) +{ + dm_table_t *tbl; + dm_table_entry_t *table_en; + uint8_t id; + + mutex_enter(&head->table_mtx); + + printf("dm_Table_destroy called with %d--%d\n", table_id, head->io_cnt); + + while (head->io_cnt != 0) + cv_wait(&head->table_cv, &head->table_mtx); + + if (table_id == DM_TABLE_ACTIVE) + id = head->cur_active_table; + else + id = 1 - head->cur_active_table; + + tbl = &head->tables[id]; + + while (!SLIST_EMPTY(tbl)) { /* List Deletion. */ + table_en = SLIST_FIRST(tbl); + /* + * Remove target specific config data. After successfull + * call table_en->target_config must be set to NULL. + */ + table_en->target->destroy(table_en); + + SLIST_REMOVE_HEAD(tbl, next); + + kmem_free(table_en, sizeof(*table_en)); + } + + mutex_exit(&head->table_mtx); + + return 0; +} + +/* + * Return length of active table in device. + */ +uint64_t +dm_table_size(dm_table_head_t *head) +{ + dm_table_t *tbl; + dm_table_entry_t *table_en; + uint64_t length; + uint8_t id; + + length = 0; + + id = dm_table_busy(head, DM_TABLE_ACTIVE); + + /* Select active table */ + tbl = &head->tables[id]; + + /* + * Find out what tables I want to select. + * if length => rawblkno then we should used that table. + */ + SLIST_FOREACH(table_en, tbl, next) + length += table_en->length; + + dm_table_unbusy(head); + + return length / DEV_BSIZE; +} + +/* + * Return > 0 if table is at least one table entry (returns number of entries) + * and return 0 if there is not. Target count returned from this function + * doesn't need to be true when userspace user receive it (after return + * there can be dm_dev_resume_ioctl), therfore this isonly informative. + */ +int +dm_table_get_target_count(dm_table_head_t *head, uint8_t table_id) +{ + dm_table_entry_t *table_en; + dm_table_t *tbl; + uint32_t target_count; + uint8_t id; + + target_count = 0; + + id = dm_table_busy(head, table_id); + + tbl = &head->tables[id]; + + SLIST_FOREACH(table_en, tbl, next) + target_count++; + + dm_table_unbusy(head); + + return target_count; +} + + +/* + * Initialize table_head structures, I'm trying to keep this structure as + * opaque as possible. + */ +void +dm_table_head_init(dm_table_head_t *head) +{ + head->cur_active_table = 0; + head->io_cnt = 0; + + /* Initialize tables. */ + SLIST_INIT(&head->tables[0]); + SLIST_INIT(&head->tables[1]); + + mutex_init(&head->table_mtx, MUTEX_DEFAULT, IPL_NONE); + cv_init(&head->table_cv, "dm_io"); +} + +/* + * Destroy all variables in table_head + */ +void +dm_table_head_destroy(dm_table_head_t *head) +{ + KASSERT(!mutex_owned(&head->table_mtx)); + KASSERT(!cv_has_waiters(&head->table_cv)); + /* tables doens't exists when I call this routine, therefore + it doesn't make sense to have io_cnt != 0 */ + KASSERT(head->io_cnt == 0); + + cv_destroy(&head->table_cv); + mutex_destroy(&head->table_mtx); +} |
