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dm_table.c revision 1.12
      1  1.12   tkusumi /*        $NetBSD: dm_table.c,v 1.12 2019/12/07 15:28:39 tkusumi Exp $      */
      2   1.2      haad 
      3   1.2      haad /*
      4   1.2      haad  * Copyright (c) 2008 The NetBSD Foundation, Inc.
      5   1.2      haad  * All rights reserved.
      6   1.2      haad  *
      7   1.2      haad  * This code is derived from software contributed to The NetBSD Foundation
      8   1.2      haad  * by Adam Hamsik.
      9   1.2      haad  *
     10   1.2      haad  * Redistribution and use in source and binary forms, with or without
     11   1.2      haad  * modification, are permitted provided that the following conditions
     12   1.2      haad  * are met:
     13   1.2      haad  * 1. Redistributions of source code must retain the above copyright
     14   1.2      haad  *    notice, this list of conditions and the following disclaimer.
     15   1.2      haad  * 2. Redistributions in binary form must reproduce the above copyright
     16   1.2      haad  *    notice, this list of conditions and the following disclaimer in the
     17   1.2      haad  *    documentation and/or other materials provided with the distribution.
     18   1.2      haad  *
     19   1.2      haad  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     20   1.2      haad  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     21   1.2      haad  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     22   1.2      haad  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     23   1.2      haad  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     24   1.2      haad  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     25   1.2      haad  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     26   1.2      haad  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     27   1.2      haad  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     28   1.2      haad  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     29   1.2      haad  * POSSIBILITY OF SUCH DAMAGE.
     30   1.2      haad  */
     31   1.8  christos #include <sys/cdefs.h>
     32  1.12   tkusumi __KERNEL_RCSID(0, "$NetBSD: dm_table.c,v 1.12 2019/12/07 15:28:39 tkusumi Exp $");
     33   1.2      haad 
     34   1.2      haad #include <sys/types.h>
     35   1.2      haad #include <sys/param.h>
     36   1.2      haad 
     37   1.2      haad #include <sys/kmem.h>
     38   1.2      haad 
     39   1.2      haad #include "dm.h"
     40   1.2      haad 
     41   1.2      haad /*
     42   1.2      haad  * There are two types of users of this interface:
     43   1.5      haad  *
     44   1.2      haad  * a) Readers such as
     45   1.2      haad  *    dmstrategy, dmgetdisklabel, dmsize, dm_dev_status_ioctl,
     46   1.2      haad  *    dm_table_deps_ioctl, dm_table_status_ioctl, dm_table_reload_ioctl
     47   1.2      haad  *
     48   1.2      haad  * b) Writers such as
     49   1.2      haad  *    dm_dev_remove_ioctl, dm_dev_resume_ioctl, dm_table_clear_ioctl
     50   1.2      haad  *
     51   1.2      haad  * Writers can work with table_head only when there are no readers. I
     52   1.2      haad  * use reference counting on io_cnt.
     53   1.2      haad  *
     54   1.2      haad  */
     55   1.2      haad 
     56   1.5      haad static int dm_table_busy(dm_table_head_t *, uint8_t);
     57   1.2      haad static void dm_table_unbusy(dm_table_head_t *);
     58   1.2      haad 
     59   1.2      haad /*
     60   1.2      haad  * Function to increment table user reference counter. Return id
     61   1.2      haad  * of table_id table.
     62   1.2      haad  * DM_TABLE_ACTIVE will return active table id.
     63   1.2      haad  * DM_TABLE_INACTIVE will return inactive table id.
     64   1.2      haad  */
     65   1.2      haad static int
     66  1.12   tkusumi dm_table_busy(dm_table_head_t *head, uint8_t table_id)
     67   1.2      haad {
     68   1.2      haad 	uint8_t id;
     69   1.2      haad 
     70   1.2      haad 	mutex_enter(&head->table_mtx);
     71   1.2      haad 
     72   1.2      haad 	if (table_id == DM_TABLE_ACTIVE)
     73   1.2      haad 		id = head->cur_active_table;
     74   1.2      haad 	else
     75   1.2      haad 		id = 1 - head->cur_active_table;
     76   1.2      haad 
     77   1.2      haad 	head->io_cnt++;
     78   1.2      haad 
     79   1.2      haad 	mutex_exit(&head->table_mtx);
     80   1.2      haad 	return id;
     81   1.2      haad }
     82   1.8  christos 
     83   1.2      haad /*
     84   1.2      haad  * Function release table lock and eventually wakeup all waiters.
     85   1.2      haad  */
     86   1.2      haad static void
     87  1.12   tkusumi dm_table_unbusy(dm_table_head_t *head)
     88   1.2      haad {
     89   1.2      haad 	KASSERT(head->io_cnt != 0);
     90   1.2      haad 
     91   1.2      haad 	mutex_enter(&head->table_mtx);
     92   1.5      haad 
     93   1.2      haad 	if (--head->io_cnt == 0)
     94   1.2      haad 		cv_broadcast(&head->table_cv);
     95   1.5      haad 
     96   1.2      haad 	mutex_exit(&head->table_mtx);
     97   1.2      haad }
     98   1.8  christos 
     99   1.2      haad /*
    100   1.2      haad  * Return current active table to caller, increment io_cnt reference counter.
    101   1.2      haad  */
    102   1.2      haad dm_table_t *
    103  1.12   tkusumi dm_table_get_entry(dm_table_head_t *head, uint8_t table_id)
    104   1.2      haad {
    105   1.2      haad 	uint8_t id;
    106   1.2      haad 
    107   1.2      haad 	id = dm_table_busy(head, table_id);
    108   1.5      haad 
    109   1.2      haad 	return &head->tables[id];
    110   1.2      haad }
    111   1.2      haad /*
    112   1.2      haad  * Decrement io reference counter and wake up all callers, with table_head cv.
    113   1.2      haad  */
    114   1.2      haad void
    115  1.12   tkusumi dm_table_release(dm_table_head_t *head, uint8_t table_id)
    116   1.2      haad {
    117   1.2      haad 	dm_table_unbusy(head);
    118   1.2      haad }
    119   1.8  christos 
    120   1.2      haad /*
    121   1.2      haad  * Switch table from inactive to active mode. Have to wait until io_cnt is 0.
    122   1.2      haad  */
    123   1.2      haad void
    124  1.12   tkusumi dm_table_switch_tables(dm_table_head_t *head)
    125   1.2      haad {
    126   1.2      haad 	mutex_enter(&head->table_mtx);
    127   1.2      haad 
    128   1.2      haad 	while (head->io_cnt != 0)
    129   1.2      haad 		cv_wait(&head->table_cv, &head->table_mtx);
    130   1.2      haad 
    131   1.2      haad 	head->cur_active_table = 1 - head->cur_active_table;
    132   1.2      haad 
    133   1.2      haad 	mutex_exit(&head->table_mtx);
    134   1.2      haad }
    135   1.8  christos 
    136   1.2      haad /*
    137   1.2      haad  * Destroy all table data. This function can run when there are no
    138   1.2      haad  * readers on table lists.
    139   1.2      haad  *
    140   1.2      haad  * XXX Is it ok to call kmem_free and potentialy VOP_CLOSE with held mutex ?xs
    141   1.2      haad  */
    142   1.2      haad int
    143  1.12   tkusumi dm_table_destroy(dm_table_head_t *head, uint8_t table_id)
    144   1.2      haad {
    145   1.5      haad 	dm_table_t *tbl;
    146   1.2      haad 	dm_table_entry_t *table_en;
    147   1.2      haad 	uint8_t id;
    148   1.2      haad 
    149   1.2      haad 	mutex_enter(&head->table_mtx);
    150   1.2      haad 
    151   1.4     joerg 	aprint_debug("dm_Table_destroy called with %d--%d\n", table_id, head->io_cnt);
    152   1.4     joerg 
    153   1.2      haad 	while (head->io_cnt != 0)
    154   1.2      haad 		cv_wait(&head->table_cv, &head->table_mtx);
    155   1.2      haad 
    156   1.2      haad 	if (table_id == DM_TABLE_ACTIVE)
    157   1.2      haad 		id = head->cur_active_table;
    158   1.2      haad 	else
    159   1.2      haad 		id = 1 - head->cur_active_table;
    160   1.5      haad 
    161   1.2      haad 	tbl = &head->tables[id];
    162   1.5      haad 
    163  1.11   tkusumi 	while ((table_en = SLIST_FIRST(tbl)) != NULL) {
    164  1.11   tkusumi 		SLIST_REMOVE(tbl, table_en, dm_table_entry, next);
    165  1.10   tkusumi 		if (table_en->target->destroy(table_en) == 0)
    166  1.10   tkusumi 			table_en->target_config = NULL;
    167   1.5      haad 
    168   1.2      haad 		kmem_free(table_en, sizeof(*table_en));
    169   1.2      haad 	}
    170  1.11   tkusumi 	KASSERT(SLIST_EMPTY(tbl));
    171   1.2      haad 
    172   1.2      haad 	mutex_exit(&head->table_mtx);
    173   1.5      haad 
    174   1.2      haad 	return 0;
    175   1.2      haad }
    176   1.8  christos 
    177   1.2      haad /*
    178   1.2      haad  * Return length of active table in device.
    179   1.2      haad  */
    180   1.7     ahoka static inline uint64_t
    181  1.12   tkusumi dm_table_size_impl(dm_table_head_t *head, int table)
    182   1.2      haad {
    183   1.5      haad 	dm_table_t *tbl;
    184   1.2      haad 	dm_table_entry_t *table_en;
    185   1.2      haad 	uint64_t length;
    186   1.2      haad 	uint8_t id;
    187   1.5      haad 
    188   1.2      haad 	length = 0;
    189   1.2      haad 
    190   1.7     ahoka 	id = dm_table_busy(head, table);
    191   1.5      haad 
    192   1.2      haad 	/* Select active table */
    193   1.2      haad 	tbl = &head->tables[id];
    194   1.5      haad 
    195   1.2      haad 	/*
    196   1.2      haad 	 * Find out what tables I want to select.
    197   1.2      haad 	 * if length => rawblkno then we should used that table.
    198   1.2      haad 	 */
    199   1.2      haad 	SLIST_FOREACH(table_en, tbl, next)
    200   1.9   tkusumi 		length += table_en->length;
    201   1.2      haad 
    202   1.2      haad 	dm_table_unbusy(head);
    203   1.5      haad 
    204   1.3  jakllsch 	return length;
    205   1.2      haad }
    206   1.7     ahoka 
    207   1.7     ahoka /*
    208   1.7     ahoka  * Return length of active table in device.
    209   1.7     ahoka  */
    210   1.7     ahoka uint64_t
    211  1.12   tkusumi dm_table_size(dm_table_head_t *head)
    212   1.7     ahoka {
    213   1.7     ahoka 	return dm_table_size_impl(head, DM_TABLE_ACTIVE);
    214   1.7     ahoka }
    215   1.7     ahoka 
    216   1.7     ahoka /*
    217   1.7     ahoka  * Return length of active table in device.
    218   1.7     ahoka  */
    219   1.7     ahoka uint64_t
    220  1.12   tkusumi dm_inactive_table_size(dm_table_head_t *head)
    221   1.7     ahoka {
    222   1.7     ahoka 	return dm_table_size_impl(head, DM_TABLE_INACTIVE);
    223   1.7     ahoka }
    224   1.7     ahoka 
    225   1.2      haad /*
    226   1.6   mlelstv  * Return combined disk geometry
    227   1.6   mlelstv  */
    228   1.6   mlelstv void
    229  1.12   tkusumi dm_table_disksize(dm_table_head_t *head, uint64_t *numsecp, unsigned *secsizep)
    230   1.6   mlelstv {
    231   1.6   mlelstv 	dm_table_t *tbl;
    232   1.6   mlelstv 	dm_table_entry_t *table_en;
    233   1.6   mlelstv 	uint64_t length;
    234   1.6   mlelstv 	unsigned secsize, tsecsize;
    235   1.6   mlelstv 	uint8_t id;
    236   1.6   mlelstv 
    237   1.6   mlelstv 	length = 0;
    238   1.6   mlelstv 
    239   1.6   mlelstv 	id = dm_table_busy(head, DM_TABLE_ACTIVE);
    240   1.6   mlelstv 
    241   1.6   mlelstv 	/* Select active table */
    242   1.6   mlelstv 	tbl = &head->tables[id];
    243   1.6   mlelstv 
    244   1.6   mlelstv 	/*
    245   1.6   mlelstv 	 * Find out what tables I want to select.
    246   1.6   mlelstv 	 * if length => rawblkno then we should used that table.
    247   1.6   mlelstv 	 */
    248   1.6   mlelstv 	secsize = 0;
    249   1.6   mlelstv 	SLIST_FOREACH(table_en, tbl, next) {
    250   1.9   tkusumi 		length += table_en->length;
    251   1.9   tkusumi 		(void)table_en->target->secsize(table_en, &tsecsize);
    252   1.9   tkusumi 		if (secsize < tsecsize)
    253   1.9   tkusumi 			secsize = tsecsize;
    254   1.6   mlelstv 	}
    255   1.6   mlelstv 	*numsecp = secsize > 0 ? dbtob(length) / secsize : 0;
    256   1.6   mlelstv 	*secsizep = secsize;
    257   1.6   mlelstv 
    258   1.6   mlelstv 	dm_table_unbusy(head);
    259   1.6   mlelstv }
    260   1.8  christos 
    261   1.6   mlelstv /*
    262   1.2      haad  * Return > 0 if table is at least one table entry (returns number of entries)
    263   1.2      haad  * and return 0 if there is not. Target count returned from this function
    264   1.2      haad  * doesn't need to be true when userspace user receive it (after return
    265   1.2      haad  * there can be dm_dev_resume_ioctl), therfore this isonly informative.
    266   1.2      haad  */
    267   1.2      haad int
    268  1.12   tkusumi dm_table_get_target_count(dm_table_head_t *head, uint8_t table_id)
    269   1.5      haad {
    270   1.2      haad 	dm_table_entry_t *table_en;
    271   1.2      haad 	dm_table_t *tbl;
    272   1.2      haad 	uint32_t target_count;
    273   1.2      haad 	uint8_t id;
    274   1.2      haad 
    275   1.2      haad 	target_count = 0;
    276   1.2      haad 
    277   1.2      haad 	id = dm_table_busy(head, table_id);
    278   1.2      haad 
    279   1.2      haad 	tbl = &head->tables[id];
    280   1.2      haad 
    281   1.2      haad 	SLIST_FOREACH(table_en, tbl, next)
    282   1.9   tkusumi 		target_count++;
    283   1.2      haad 
    284   1.2      haad 	dm_table_unbusy(head);
    285   1.5      haad 
    286   1.2      haad 	return target_count;
    287   1.2      haad }
    288   1.2      haad 
    289   1.2      haad 
    290   1.2      haad /*
    291   1.2      haad  * Initialize table_head structures, I'm trying to keep this structure as
    292   1.2      haad  * opaque as possible.
    293   1.2      haad  */
    294   1.2      haad void
    295  1.12   tkusumi dm_table_head_init(dm_table_head_t *head)
    296   1.2      haad {
    297   1.2      haad 	head->cur_active_table = 0;
    298   1.2      haad 	head->io_cnt = 0;
    299   1.5      haad 
    300   1.2      haad 	/* Initialize tables. */
    301   1.2      haad 	SLIST_INIT(&head->tables[0]);
    302   1.2      haad 	SLIST_INIT(&head->tables[1]);
    303   1.2      haad 
    304   1.2      haad 	mutex_init(&head->table_mtx, MUTEX_DEFAULT, IPL_NONE);
    305   1.2      haad 	cv_init(&head->table_cv, "dm_io");
    306   1.2      haad }
    307   1.8  christos 
    308   1.2      haad /*
    309   1.2      haad  * Destroy all variables in table_head
    310   1.2      haad  */
    311   1.2      haad void
    312  1.12   tkusumi dm_table_head_destroy(dm_table_head_t *head)
    313   1.2      haad {
    314   1.2      haad 	KASSERT(!mutex_owned(&head->table_mtx));
    315   1.2      haad 	KASSERT(!cv_has_waiters(&head->table_cv));
    316   1.5      haad 	/* tables doens't exists when I call this routine, therefore it
    317   1.5      haad 	 * doesn't make sense to have io_cnt != 0 */
    318   1.5      haad 	KASSERT(head->io_cnt == 0);
    319   1.5      haad 
    320   1.2      haad 	cv_destroy(&head->table_cv);
    321   1.2      haad 	mutex_destroy(&head->table_mtx);
    322   1.2      haad }
    323