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dm_table.c revision 1.8
      1  1.8  christos /*        $NetBSD: dm_table.c,v 1.8 2018/01/05 14:22:26 christos 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  1.8  christos __KERNEL_RCSID(0, "$NetBSD: dm_table.c,v 1.8 2018/01/05 14:22:26 christos 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  1.5      haad 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 	id = 0;
     71  1.2      haad 
     72  1.2      haad 	mutex_enter(&head->table_mtx);
     73  1.2      haad 
     74  1.2      haad 	if (table_id == DM_TABLE_ACTIVE)
     75  1.2      haad 		id = head->cur_active_table;
     76  1.2      haad 	else
     77  1.2      haad 		id = 1 - head->cur_active_table;
     78  1.2      haad 
     79  1.2      haad 	head->io_cnt++;
     80  1.2      haad 
     81  1.2      haad 	mutex_exit(&head->table_mtx);
     82  1.2      haad 	return id;
     83  1.2      haad }
     84  1.8  christos 
     85  1.2      haad /*
     86  1.2      haad  * Function release table lock and eventually wakeup all waiters.
     87  1.2      haad  */
     88  1.2      haad static void
     89  1.5      haad dm_table_unbusy(dm_table_head_t * head)
     90  1.2      haad {
     91  1.2      haad 	KASSERT(head->io_cnt != 0);
     92  1.2      haad 
     93  1.2      haad 	mutex_enter(&head->table_mtx);
     94  1.5      haad 
     95  1.2      haad 	if (--head->io_cnt == 0)
     96  1.2      haad 		cv_broadcast(&head->table_cv);
     97  1.5      haad 
     98  1.2      haad 	mutex_exit(&head->table_mtx);
     99  1.2      haad }
    100  1.8  christos 
    101  1.2      haad /*
    102  1.2      haad  * Return current active table to caller, increment io_cnt reference counter.
    103  1.2      haad  */
    104  1.2      haad dm_table_t *
    105  1.5      haad dm_table_get_entry(dm_table_head_t * head, uint8_t table_id)
    106  1.2      haad {
    107  1.2      haad 	uint8_t id;
    108  1.2      haad 
    109  1.2      haad 	id = dm_table_busy(head, table_id);
    110  1.5      haad 
    111  1.2      haad 	return &head->tables[id];
    112  1.2      haad }
    113  1.2      haad /*
    114  1.2      haad  * Decrement io reference counter and wake up all callers, with table_head cv.
    115  1.2      haad  */
    116  1.2      haad void
    117  1.5      haad dm_table_release(dm_table_head_t * head, uint8_t table_id)
    118  1.2      haad {
    119  1.2      haad 	dm_table_unbusy(head);
    120  1.2      haad }
    121  1.8  christos 
    122  1.2      haad /*
    123  1.2      haad  * Switch table from inactive to active mode. Have to wait until io_cnt is 0.
    124  1.2      haad  */
    125  1.2      haad void
    126  1.5      haad dm_table_switch_tables(dm_table_head_t * head)
    127  1.2      haad {
    128  1.2      haad 	mutex_enter(&head->table_mtx);
    129  1.2      haad 
    130  1.2      haad 	while (head->io_cnt != 0)
    131  1.2      haad 		cv_wait(&head->table_cv, &head->table_mtx);
    132  1.2      haad 
    133  1.2      haad 	head->cur_active_table = 1 - head->cur_active_table;
    134  1.2      haad 
    135  1.2      haad 	mutex_exit(&head->table_mtx);
    136  1.2      haad }
    137  1.8  christos 
    138  1.2      haad /*
    139  1.2      haad  * Destroy all table data. This function can run when there are no
    140  1.2      haad  * readers on table lists.
    141  1.2      haad  *
    142  1.2      haad  * XXX Is it ok to call kmem_free and potentialy VOP_CLOSE with held mutex ?xs
    143  1.2      haad  */
    144  1.2      haad int
    145  1.5      haad dm_table_destroy(dm_table_head_t * head, uint8_t table_id)
    146  1.2      haad {
    147  1.5      haad 	dm_table_t *tbl;
    148  1.2      haad 	dm_table_entry_t *table_en;
    149  1.2      haad 	uint8_t id;
    150  1.2      haad 
    151  1.2      haad 	mutex_enter(&head->table_mtx);
    152  1.2      haad 
    153  1.4     joerg 	aprint_debug("dm_Table_destroy called with %d--%d\n", table_id, head->io_cnt);
    154  1.4     joerg 
    155  1.2      haad 	while (head->io_cnt != 0)
    156  1.2      haad 		cv_wait(&head->table_cv, &head->table_mtx);
    157  1.2      haad 
    158  1.2      haad 	if (table_id == DM_TABLE_ACTIVE)
    159  1.2      haad 		id = head->cur_active_table;
    160  1.2      haad 	else
    161  1.2      haad 		id = 1 - head->cur_active_table;
    162  1.5      haad 
    163  1.2      haad 	tbl = &head->tables[id];
    164  1.5      haad 
    165  1.5      haad 	while (!SLIST_EMPTY(tbl)) {	/* List Deletion. */
    166  1.2      haad 		table_en = SLIST_FIRST(tbl);
    167  1.2      haad 		/*
    168  1.2      haad 		 * Remove target specific config data. After successfull
    169  1.2      haad 		 * call table_en->target_config must be set to NULL.
    170  1.2      haad 		 */
    171  1.5      haad 		table_en->target->destroy(table_en);
    172  1.5      haad 
    173  1.2      haad 		SLIST_REMOVE_HEAD(tbl, next);
    174  1.2      haad 
    175  1.2      haad 		kmem_free(table_en, sizeof(*table_en));
    176  1.2      haad 	}
    177  1.2      haad 
    178  1.2      haad 	mutex_exit(&head->table_mtx);
    179  1.5      haad 
    180  1.2      haad 	return 0;
    181  1.2      haad }
    182  1.8  christos 
    183  1.2      haad /*
    184  1.2      haad  * Return length of active table in device.
    185  1.2      haad  */
    186  1.7     ahoka static inline uint64_t
    187  1.7     ahoka dm_table_size_impl(dm_table_head_t * head, int table)
    188  1.2      haad {
    189  1.5      haad 	dm_table_t *tbl;
    190  1.2      haad 	dm_table_entry_t *table_en;
    191  1.2      haad 	uint64_t length;
    192  1.2      haad 	uint8_t id;
    193  1.5      haad 
    194  1.2      haad 	length = 0;
    195  1.2      haad 
    196  1.7     ahoka 	id = dm_table_busy(head, table);
    197  1.5      haad 
    198  1.2      haad 	/* Select active table */
    199  1.2      haad 	tbl = &head->tables[id];
    200  1.5      haad 
    201  1.2      haad 	/*
    202  1.2      haad 	 * Find out what tables I want to select.
    203  1.2      haad 	 * if length => rawblkno then we should used that table.
    204  1.2      haad 	 */
    205  1.2      haad 	SLIST_FOREACH(table_en, tbl, next)
    206  1.2      haad 	    length += table_en->length;
    207  1.2      haad 
    208  1.2      haad 	dm_table_unbusy(head);
    209  1.5      haad 
    210  1.3  jakllsch 	return length;
    211  1.2      haad }
    212  1.7     ahoka 
    213  1.7     ahoka /*
    214  1.7     ahoka  * Return length of active table in device.
    215  1.7     ahoka  */
    216  1.7     ahoka uint64_t
    217  1.7     ahoka dm_table_size(dm_table_head_t * head)
    218  1.7     ahoka {
    219  1.7     ahoka 	return dm_table_size_impl(head, DM_TABLE_ACTIVE);
    220  1.7     ahoka }
    221  1.7     ahoka 
    222  1.7     ahoka /*
    223  1.7     ahoka  * Return length of active table in device.
    224  1.7     ahoka  */
    225  1.7     ahoka uint64_t
    226  1.7     ahoka dm_inactive_table_size(dm_table_head_t * head)
    227  1.7     ahoka {
    228  1.7     ahoka 	return dm_table_size_impl(head, DM_TABLE_INACTIVE);
    229  1.7     ahoka }
    230  1.7     ahoka 
    231  1.2      haad /*
    232  1.6   mlelstv  * Return combined disk geometry
    233  1.6   mlelstv  */
    234  1.6   mlelstv void
    235  1.6   mlelstv dm_table_disksize(dm_table_head_t * head, uint64_t *numsecp, unsigned *secsizep)
    236  1.6   mlelstv {
    237  1.6   mlelstv 	dm_table_t *tbl;
    238  1.6   mlelstv 	dm_table_entry_t *table_en;
    239  1.6   mlelstv 	uint64_t length;
    240  1.6   mlelstv 	unsigned secsize, tsecsize;
    241  1.6   mlelstv 	uint8_t id;
    242  1.6   mlelstv 
    243  1.6   mlelstv 	length = 0;
    244  1.6   mlelstv 
    245  1.6   mlelstv 	id = dm_table_busy(head, DM_TABLE_ACTIVE);
    246  1.6   mlelstv 
    247  1.6   mlelstv 	/* Select active table */
    248  1.6   mlelstv 	tbl = &head->tables[id];
    249  1.6   mlelstv 
    250  1.6   mlelstv 	/*
    251  1.6   mlelstv 	 * Find out what tables I want to select.
    252  1.6   mlelstv 	 * if length => rawblkno then we should used that table.
    253  1.6   mlelstv 	 */
    254  1.6   mlelstv 	secsize = 0;
    255  1.6   mlelstv 	SLIST_FOREACH(table_en, tbl, next) {
    256  1.6   mlelstv 	    length += table_en->length;
    257  1.6   mlelstv 	    (void)table_en->target->secsize(table_en, &tsecsize);
    258  1.6   mlelstv 	    if (secsize < tsecsize)
    259  1.6   mlelstv 	    	secsize = tsecsize;
    260  1.6   mlelstv 	}
    261  1.6   mlelstv 	*numsecp = secsize > 0 ? dbtob(length) / secsize : 0;
    262  1.6   mlelstv 	*secsizep = secsize;
    263  1.6   mlelstv 
    264  1.6   mlelstv 	dm_table_unbusy(head);
    265  1.6   mlelstv }
    266  1.8  christos 
    267  1.6   mlelstv /*
    268  1.2      haad  * Return > 0 if table is at least one table entry (returns number of entries)
    269  1.2      haad  * and return 0 if there is not. Target count returned from this function
    270  1.2      haad  * doesn't need to be true when userspace user receive it (after return
    271  1.2      haad  * there can be dm_dev_resume_ioctl), therfore this isonly informative.
    272  1.2      haad  */
    273  1.2      haad int
    274  1.5      haad dm_table_get_target_count(dm_table_head_t * head, uint8_t table_id)
    275  1.5      haad {
    276  1.2      haad 	dm_table_entry_t *table_en;
    277  1.2      haad 	dm_table_t *tbl;
    278  1.2      haad 	uint32_t target_count;
    279  1.2      haad 	uint8_t id;
    280  1.2      haad 
    281  1.2      haad 	target_count = 0;
    282  1.2      haad 
    283  1.2      haad 	id = dm_table_busy(head, table_id);
    284  1.2      haad 
    285  1.2      haad 	tbl = &head->tables[id];
    286  1.2      haad 
    287  1.2      haad 	SLIST_FOREACH(table_en, tbl, next)
    288  1.2      haad 	    target_count++;
    289  1.2      haad 
    290  1.2      haad 	dm_table_unbusy(head);
    291  1.5      haad 
    292  1.2      haad 	return target_count;
    293  1.2      haad }
    294  1.2      haad 
    295  1.2      haad 
    296  1.2      haad /*
    297  1.2      haad  * Initialize table_head structures, I'm trying to keep this structure as
    298  1.2      haad  * opaque as possible.
    299  1.2      haad  */
    300  1.2      haad void
    301  1.5      haad dm_table_head_init(dm_table_head_t * head)
    302  1.2      haad {
    303  1.2      haad 	head->cur_active_table = 0;
    304  1.2      haad 	head->io_cnt = 0;
    305  1.5      haad 
    306  1.2      haad 	/* Initialize tables. */
    307  1.2      haad 	SLIST_INIT(&head->tables[0]);
    308  1.2      haad 	SLIST_INIT(&head->tables[1]);
    309  1.2      haad 
    310  1.2      haad 	mutex_init(&head->table_mtx, MUTEX_DEFAULT, IPL_NONE);
    311  1.2      haad 	cv_init(&head->table_cv, "dm_io");
    312  1.2      haad }
    313  1.8  christos 
    314  1.2      haad /*
    315  1.2      haad  * Destroy all variables in table_head
    316  1.2      haad  */
    317  1.2      haad void
    318  1.5      haad dm_table_head_destroy(dm_table_head_t * head)
    319  1.2      haad {
    320  1.2      haad 	KASSERT(!mutex_owned(&head->table_mtx));
    321  1.2      haad 	KASSERT(!cv_has_waiters(&head->table_cv));
    322  1.5      haad 	/* tables doens't exists when I call this routine, therefore it
    323  1.5      haad 	 * doesn't make sense to have io_cnt != 0 */
    324  1.5      haad 	KASSERT(head->io_cnt == 0);
    325  1.5      haad 
    326  1.2      haad 	cv_destroy(&head->table_cv);
    327  1.2      haad 	mutex_destroy(&head->table_mtx);
    328  1.2      haad }
    329