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dm_table.c revision 1.7
      1  1.7     ahoka /*        $NetBSD: dm_table.c,v 1.7 2011/08/27 17:10:05 ahoka 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  1.2      haad 
     32  1.2      haad #include <sys/types.h>
     33  1.2      haad #include <sys/param.h>
     34  1.2      haad 
     35  1.2      haad #include <sys/kmem.h>
     36  1.2      haad 
     37  1.2      haad #include "dm.h"
     38  1.2      haad 
     39  1.2      haad /*
     40  1.2      haad  * There are two types of users of this interface:
     41  1.5      haad  *
     42  1.2      haad  * a) Readers such as
     43  1.2      haad  *    dmstrategy, dmgetdisklabel, dmsize, dm_dev_status_ioctl,
     44  1.2      haad  *    dm_table_deps_ioctl, dm_table_status_ioctl, dm_table_reload_ioctl
     45  1.2      haad  *
     46  1.2      haad  * b) Writers such as
     47  1.2      haad  *    dm_dev_remove_ioctl, dm_dev_resume_ioctl, dm_table_clear_ioctl
     48  1.2      haad  *
     49  1.2      haad  * Writers can work with table_head only when there are no readers. I
     50  1.2      haad  * use reference counting on io_cnt.
     51  1.2      haad  *
     52  1.2      haad  */
     53  1.2      haad 
     54  1.5      haad static int dm_table_busy(dm_table_head_t *, uint8_t);
     55  1.2      haad static void dm_table_unbusy(dm_table_head_t *);
     56  1.2      haad 
     57  1.2      haad /*
     58  1.2      haad  * Function to increment table user reference counter. Return id
     59  1.2      haad  * of table_id table.
     60  1.2      haad  * DM_TABLE_ACTIVE will return active table id.
     61  1.2      haad  * DM_TABLE_INACTIVE will return inactive table id.
     62  1.2      haad  */
     63  1.2      haad static int
     64  1.5      haad dm_table_busy(dm_table_head_t * head, uint8_t table_id)
     65  1.2      haad {
     66  1.2      haad 	uint8_t id;
     67  1.2      haad 
     68  1.2      haad 	id = 0;
     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  1.2      haad /*
     83  1.2      haad  * Function release table lock and eventually wakeup all waiters.
     84  1.2      haad  */
     85  1.2      haad static void
     86  1.5      haad dm_table_unbusy(dm_table_head_t * head)
     87  1.2      haad {
     88  1.2      haad 	KASSERT(head->io_cnt != 0);
     89  1.2      haad 
     90  1.2      haad 	mutex_enter(&head->table_mtx);
     91  1.5      haad 
     92  1.2      haad 	if (--head->io_cnt == 0)
     93  1.2      haad 		cv_broadcast(&head->table_cv);
     94  1.5      haad 
     95  1.2      haad 	mutex_exit(&head->table_mtx);
     96  1.2      haad }
     97  1.2      haad /*
     98  1.2      haad  * Return current active table to caller, increment io_cnt reference counter.
     99  1.2      haad  */
    100  1.2      haad dm_table_t *
    101  1.5      haad dm_table_get_entry(dm_table_head_t * head, uint8_t table_id)
    102  1.2      haad {
    103  1.2      haad 	uint8_t id;
    104  1.2      haad 
    105  1.2      haad 	id = dm_table_busy(head, table_id);
    106  1.5      haad 
    107  1.2      haad 	return &head->tables[id];
    108  1.2      haad }
    109  1.2      haad /*
    110  1.2      haad  * Decrement io reference counter and wake up all callers, with table_head cv.
    111  1.2      haad  */
    112  1.2      haad void
    113  1.5      haad dm_table_release(dm_table_head_t * head, uint8_t table_id)
    114  1.2      haad {
    115  1.2      haad 	dm_table_unbusy(head);
    116  1.2      haad }
    117  1.2      haad /*
    118  1.2      haad  * Switch table from inactive to active mode. Have to wait until io_cnt is 0.
    119  1.2      haad  */
    120  1.2      haad void
    121  1.5      haad dm_table_switch_tables(dm_table_head_t * head)
    122  1.2      haad {
    123  1.2      haad 	mutex_enter(&head->table_mtx);
    124  1.2      haad 
    125  1.2      haad 	while (head->io_cnt != 0)
    126  1.2      haad 		cv_wait(&head->table_cv, &head->table_mtx);
    127  1.2      haad 
    128  1.2      haad 	head->cur_active_table = 1 - head->cur_active_table;
    129  1.2      haad 
    130  1.2      haad 	mutex_exit(&head->table_mtx);
    131  1.2      haad }
    132  1.2      haad /*
    133  1.2      haad  * Destroy all table data. This function can run when there are no
    134  1.2      haad  * readers on table lists.
    135  1.2      haad  *
    136  1.2      haad  * XXX Is it ok to call kmem_free and potentialy VOP_CLOSE with held mutex ?xs
    137  1.2      haad  */
    138  1.2      haad int
    139  1.5      haad dm_table_destroy(dm_table_head_t * head, uint8_t table_id)
    140  1.2      haad {
    141  1.5      haad 	dm_table_t *tbl;
    142  1.2      haad 	dm_table_entry_t *table_en;
    143  1.2      haad 	uint8_t id;
    144  1.2      haad 
    145  1.2      haad 	mutex_enter(&head->table_mtx);
    146  1.2      haad 
    147  1.4     joerg 	aprint_debug("dm_Table_destroy called with %d--%d\n", table_id, head->io_cnt);
    148  1.4     joerg 
    149  1.2      haad 	while (head->io_cnt != 0)
    150  1.2      haad 		cv_wait(&head->table_cv, &head->table_mtx);
    151  1.2      haad 
    152  1.2      haad 	if (table_id == DM_TABLE_ACTIVE)
    153  1.2      haad 		id = head->cur_active_table;
    154  1.2      haad 	else
    155  1.2      haad 		id = 1 - head->cur_active_table;
    156  1.5      haad 
    157  1.2      haad 	tbl = &head->tables[id];
    158  1.5      haad 
    159  1.5      haad 	while (!SLIST_EMPTY(tbl)) {	/* List Deletion. */
    160  1.2      haad 		table_en = SLIST_FIRST(tbl);
    161  1.2      haad 		/*
    162  1.2      haad 		 * Remove target specific config data. After successfull
    163  1.2      haad 		 * call table_en->target_config must be set to NULL.
    164  1.2      haad 		 */
    165  1.5      haad 		table_en->target->destroy(table_en);
    166  1.5      haad 
    167  1.2      haad 		SLIST_REMOVE_HEAD(tbl, next);
    168  1.2      haad 
    169  1.2      haad 		kmem_free(table_en, sizeof(*table_en));
    170  1.2      haad 	}
    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  1.2      haad /*
    177  1.2      haad  * Return length of active table in device.
    178  1.2      haad  */
    179  1.7     ahoka static inline uint64_t
    180  1.7     ahoka dm_table_size_impl(dm_table_head_t * head, int table)
    181  1.2      haad {
    182  1.5      haad 	dm_table_t *tbl;
    183  1.2      haad 	dm_table_entry_t *table_en;
    184  1.2      haad 	uint64_t length;
    185  1.2      haad 	uint8_t id;
    186  1.5      haad 
    187  1.2      haad 	length = 0;
    188  1.2      haad 
    189  1.7     ahoka 	id = dm_table_busy(head, table);
    190  1.5      haad 
    191  1.2      haad 	/* Select active table */
    192  1.2      haad 	tbl = &head->tables[id];
    193  1.5      haad 
    194  1.2      haad 	/*
    195  1.2      haad 	 * Find out what tables I want to select.
    196  1.2      haad 	 * if length => rawblkno then we should used that table.
    197  1.2      haad 	 */
    198  1.2      haad 	SLIST_FOREACH(table_en, tbl, next)
    199  1.2      haad 	    length += table_en->length;
    200  1.2      haad 
    201  1.2      haad 	dm_table_unbusy(head);
    202  1.5      haad 
    203  1.3  jakllsch 	return length;
    204  1.2      haad }
    205  1.7     ahoka 
    206  1.7     ahoka /*
    207  1.7     ahoka  * Return length of active table in device.
    208  1.7     ahoka  */
    209  1.7     ahoka uint64_t
    210  1.7     ahoka dm_table_size(dm_table_head_t * head)
    211  1.7     ahoka {
    212  1.7     ahoka 	return dm_table_size_impl(head, DM_TABLE_ACTIVE);
    213  1.7     ahoka }
    214  1.7     ahoka 
    215  1.7     ahoka /*
    216  1.7     ahoka  * Return length of active table in device.
    217  1.7     ahoka  */
    218  1.7     ahoka uint64_t
    219  1.7     ahoka dm_inactive_table_size(dm_table_head_t * head)
    220  1.7     ahoka {
    221  1.7     ahoka 	return dm_table_size_impl(head, DM_TABLE_INACTIVE);
    222  1.7     ahoka }
    223  1.7     ahoka 
    224  1.2      haad /*
    225  1.6   mlelstv  * Return combined disk geometry
    226  1.6   mlelstv  */
    227  1.6   mlelstv void
    228  1.6   mlelstv dm_table_disksize(dm_table_head_t * head, uint64_t *numsecp, unsigned *secsizep)
    229  1.6   mlelstv {
    230  1.6   mlelstv 	dm_table_t *tbl;
    231  1.6   mlelstv 	dm_table_entry_t *table_en;
    232  1.6   mlelstv 	uint64_t length;
    233  1.6   mlelstv 	unsigned secsize, tsecsize;
    234  1.6   mlelstv 	uint8_t id;
    235  1.6   mlelstv 
    236  1.6   mlelstv 	length = 0;
    237  1.6   mlelstv 
    238  1.6   mlelstv 	id = dm_table_busy(head, DM_TABLE_ACTIVE);
    239  1.6   mlelstv 
    240  1.6   mlelstv 	/* Select active table */
    241  1.6   mlelstv 	tbl = &head->tables[id];
    242  1.6   mlelstv 
    243  1.6   mlelstv 	/*
    244  1.6   mlelstv 	 * Find out what tables I want to select.
    245  1.6   mlelstv 	 * if length => rawblkno then we should used that table.
    246  1.6   mlelstv 	 */
    247  1.6   mlelstv 	secsize = 0;
    248  1.6   mlelstv 	SLIST_FOREACH(table_en, tbl, next) {
    249  1.6   mlelstv 	    length += table_en->length;
    250  1.6   mlelstv 	    (void)table_en->target->secsize(table_en, &tsecsize);
    251  1.6   mlelstv 	    if (secsize < tsecsize)
    252  1.6   mlelstv 	    	secsize = tsecsize;
    253  1.6   mlelstv 	}
    254  1.6   mlelstv 	*numsecp = secsize > 0 ? dbtob(length) / secsize : 0;
    255  1.6   mlelstv 	*secsizep = secsize;
    256  1.6   mlelstv 
    257  1.6   mlelstv 	dm_table_unbusy(head);
    258  1.6   mlelstv }
    259  1.6   mlelstv /*
    260  1.2      haad  * Return > 0 if table is at least one table entry (returns number of entries)
    261  1.2      haad  * and return 0 if there is not. Target count returned from this function
    262  1.2      haad  * doesn't need to be true when userspace user receive it (after return
    263  1.2      haad  * there can be dm_dev_resume_ioctl), therfore this isonly informative.
    264  1.2      haad  */
    265  1.2      haad int
    266  1.5      haad dm_table_get_target_count(dm_table_head_t * head, uint8_t table_id)
    267  1.5      haad {
    268  1.2      haad 	dm_table_entry_t *table_en;
    269  1.2      haad 	dm_table_t *tbl;
    270  1.2      haad 	uint32_t target_count;
    271  1.2      haad 	uint8_t id;
    272  1.2      haad 
    273  1.2      haad 	target_count = 0;
    274  1.2      haad 
    275  1.2      haad 	id = dm_table_busy(head, table_id);
    276  1.2      haad 
    277  1.2      haad 	tbl = &head->tables[id];
    278  1.2      haad 
    279  1.2      haad 	SLIST_FOREACH(table_en, tbl, next)
    280  1.2      haad 	    target_count++;
    281  1.2      haad 
    282  1.2      haad 	dm_table_unbusy(head);
    283  1.5      haad 
    284  1.2      haad 	return target_count;
    285  1.2      haad }
    286  1.2      haad 
    287  1.2      haad 
    288  1.2      haad /*
    289  1.2      haad  * Initialize table_head structures, I'm trying to keep this structure as
    290  1.2      haad  * opaque as possible.
    291  1.2      haad  */
    292  1.2      haad void
    293  1.5      haad dm_table_head_init(dm_table_head_t * head)
    294  1.2      haad {
    295  1.2      haad 	head->cur_active_table = 0;
    296  1.2      haad 	head->io_cnt = 0;
    297  1.5      haad 
    298  1.2      haad 	/* Initialize tables. */
    299  1.2      haad 	SLIST_INIT(&head->tables[0]);
    300  1.2      haad 	SLIST_INIT(&head->tables[1]);
    301  1.2      haad 
    302  1.2      haad 	mutex_init(&head->table_mtx, MUTEX_DEFAULT, IPL_NONE);
    303  1.2      haad 	cv_init(&head->table_cv, "dm_io");
    304  1.2      haad }
    305  1.2      haad /*
    306  1.2      haad  * Destroy all variables in table_head
    307  1.2      haad  */
    308  1.2      haad void
    309  1.5      haad dm_table_head_destroy(dm_table_head_t * head)
    310  1.2      haad {
    311  1.2      haad 	KASSERT(!mutex_owned(&head->table_mtx));
    312  1.2      haad 	KASSERT(!cv_has_waiters(&head->table_cv));
    313  1.5      haad 	/* tables doens't exists when I call this routine, therefore it
    314  1.5      haad 	 * doesn't make sense to have io_cnt != 0 */
    315  1.5      haad 	KASSERT(head->io_cnt == 0);
    316  1.5      haad 
    317  1.2      haad 	cv_destroy(&head->table_cv);
    318  1.2      haad 	mutex_destroy(&head->table_mtx);
    319  1.2      haad }
    320