dm.c (62f75c2f3244553b1290447abd1f1e6b1144d3e9) dm.c (f32c10b09940cffc3620ce111315ec44343fd3ca)
1/*
2 * Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
3 * Copyright (C) 2004 Red Hat, Inc. All rights reserved.
4 *
5 * This file is released under the GPL.
6 */
7
8#include "dm.h"

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21#include <linux/hdreg.h>
22#include <linux/blktrace_api.h>
23
24static const char *_name = DM_NAME;
25
26static unsigned int major = 0;
27static unsigned int _major = 0;
28
1/*
2 * Copyright (C) 2001, 2002 Sistina Software (UK) Limited.
3 * Copyright (C) 2004 Red Hat, Inc. All rights reserved.
4 *
5 * This file is released under the GPL.
6 */
7
8#include "dm.h"

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21#include <linux/hdreg.h>
22#include <linux/blktrace_api.h>
23
24static const char *_name = DM_NAME;
25
26static unsigned int major = 0;
27static unsigned int _major = 0;
28
29static DEFINE_SPINLOCK(_minor_lock);
29/*
30 * One of these is allocated per bio.
31 */
32struct dm_io {
33 struct mapped_device *md;
34 int error;
35 struct bio *bio;
36 atomic_t io_count;

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741
742 dm_table_put(map);
743 return r;
744}
745
746/*-----------------------------------------------------------------
747 * An IDR is used to keep track of allocated minor numbers.
748 *---------------------------------------------------------------*/
30/*
31 * One of these is allocated per bio.
32 */
33struct dm_io {
34 struct mapped_device *md;
35 int error;
36 struct bio *bio;
37 atomic_t io_count;

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742
743 dm_table_put(map);
744 return r;
745}
746
747/*-----------------------------------------------------------------
748 * An IDR is used to keep track of allocated minor numbers.
749 *---------------------------------------------------------------*/
749static DEFINE_MUTEX(_minor_lock);
750static DEFINE_IDR(_minor_idr);
751
752static void free_minor(unsigned int minor)
753{
750static DEFINE_IDR(_minor_idr);
751
752static void free_minor(unsigned int minor)
753{
754 mutex_lock(&_minor_lock);
754 spin_lock(&_minor_lock);
755 idr_remove(&_minor_idr, minor);
755 idr_remove(&_minor_idr, minor);
756 mutex_unlock(&_minor_lock);
756 spin_unlock(&_minor_lock);
757}
758
759/*
760 * See if the device with a specific minor # is free.
761 */
762static int specific_minor(struct mapped_device *md, unsigned int minor)
763{
764 int r, m;
765
766 if (minor >= (1 << MINORBITS))
767 return -EINVAL;
768
769 r = idr_pre_get(&_minor_idr, GFP_KERNEL);
770 if (!r)
771 return -ENOMEM;
772
757}
758
759/*
760 * See if the device with a specific minor # is free.
761 */
762static int specific_minor(struct mapped_device *md, unsigned int minor)
763{
764 int r, m;
765
766 if (minor >= (1 << MINORBITS))
767 return -EINVAL;
768
769 r = idr_pre_get(&_minor_idr, GFP_KERNEL);
770 if (!r)
771 return -ENOMEM;
772
773 mutex_lock(&_minor_lock);
773 spin_lock(&_minor_lock);
774
775 if (idr_find(&_minor_idr, minor)) {
776 r = -EBUSY;
777 goto out;
778 }
779
780 r = idr_get_new_above(&_minor_idr, MINOR_ALLOCED, minor, &m);
781 if (r)
782 goto out;
783
784 if (m != minor) {
785 idr_remove(&_minor_idr, m);
786 r = -EBUSY;
787 goto out;
788 }
789
790out:
774
775 if (idr_find(&_minor_idr, minor)) {
776 r = -EBUSY;
777 goto out;
778 }
779
780 r = idr_get_new_above(&_minor_idr, MINOR_ALLOCED, minor, &m);
781 if (r)
782 goto out;
783
784 if (m != minor) {
785 idr_remove(&_minor_idr, m);
786 r = -EBUSY;
787 goto out;
788 }
789
790out:
791 mutex_unlock(&_minor_lock);
791 spin_unlock(&_minor_lock);
792 return r;
793}
794
795static int next_free_minor(struct mapped_device *md, unsigned int *minor)
796{
797 int r;
798 unsigned int m;
799
800 r = idr_pre_get(&_minor_idr, GFP_KERNEL);
801 if (!r)
802 return -ENOMEM;
803
792 return r;
793}
794
795static int next_free_minor(struct mapped_device *md, unsigned int *minor)
796{
797 int r;
798 unsigned int m;
799
800 r = idr_pre_get(&_minor_idr, GFP_KERNEL);
801 if (!r)
802 return -ENOMEM;
803
804 mutex_lock(&_minor_lock);
804 spin_lock(&_minor_lock);
805
806 r = idr_get_new(&_minor_idr, MINOR_ALLOCED, &m);
807 if (r) {
808 goto out;
809 }
810
811 if (m >= (1 << MINORBITS)) {
812 idr_remove(&_minor_idr, m);
813 r = -ENOSPC;
814 goto out;
815 }
816
817 *minor = m;
818
819out:
805
806 r = idr_get_new(&_minor_idr, MINOR_ALLOCED, &m);
807 if (r) {
808 goto out;
809 }
810
811 if (m >= (1 << MINORBITS)) {
812 idr_remove(&_minor_idr, m);
813 r = -ENOSPC;
814 goto out;
815 }
816
817 *minor = m;
818
819out:
820 mutex_unlock(&_minor_lock);
820 spin_unlock(&_minor_lock);
821 return r;
822}
823
824static struct block_device_operations dm_blk_dops;
825
826/*
827 * Allocate and initialise a blank device with a given minor.
828 */

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882 add_disk(md->disk);
883 format_dev_t(md->name, MKDEV(_major, minor));
884
885 atomic_set(&md->pending, 0);
886 init_waitqueue_head(&md->wait);
887 init_waitqueue_head(&md->eventq);
888
889 /* Populate the mapping, nobody knows we exist yet */
821 return r;
822}
823
824static struct block_device_operations dm_blk_dops;
825
826/*
827 * Allocate and initialise a blank device with a given minor.
828 */

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882 add_disk(md->disk);
883 format_dev_t(md->name, MKDEV(_major, minor));
884
885 atomic_set(&md->pending, 0);
886 init_waitqueue_head(&md->wait);
887 init_waitqueue_head(&md->eventq);
888
889 /* Populate the mapping, nobody knows we exist yet */
890 mutex_lock(&_minor_lock);
890 spin_lock(&_minor_lock);
891 old_md = idr_replace(&_minor_idr, md, minor);
891 old_md = idr_replace(&_minor_idr, md, minor);
892 mutex_unlock(&_minor_lock);
892 spin_unlock(&_minor_lock);
893
894 BUG_ON(old_md != MINOR_ALLOCED);
895
896 return md;
897
898 bad4:
899 mempool_destroy(md->tio_pool);
900 bad3:

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1015static struct mapped_device *dm_find_md(dev_t dev)
1016{
1017 struct mapped_device *md;
1018 unsigned minor = MINOR(dev);
1019
1020 if (MAJOR(dev) != _major || minor >= (1 << MINORBITS))
1021 return NULL;
1022
893
894 BUG_ON(old_md != MINOR_ALLOCED);
895
896 return md;
897
898 bad4:
899 mempool_destroy(md->tio_pool);
900 bad3:

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1015static struct mapped_device *dm_find_md(dev_t dev)
1016{
1017 struct mapped_device *md;
1018 unsigned minor = MINOR(dev);
1019
1020 if (MAJOR(dev) != _major || minor >= (1 << MINORBITS))
1021 return NULL;
1022
1023 mutex_lock(&_minor_lock);
1023 spin_lock(&_minor_lock);
1024
1025 md = idr_find(&_minor_idr, minor);
1026 if (md && (md == MINOR_ALLOCED || (dm_disk(md)->first_minor != minor)))
1027 md = NULL;
1028
1024
1025 md = idr_find(&_minor_idr, minor);
1026 if (md && (md == MINOR_ALLOCED || (dm_disk(md)->first_minor != minor)))
1027 md = NULL;
1028
1029 mutex_unlock(&_minor_lock);
1029 spin_unlock(&_minor_lock);
1030
1031 return md;
1032}
1033
1034struct mapped_device *dm_get_md(dev_t dev)
1035{
1036 struct mapped_device *md = dm_find_md(dev);
1037

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1055{
1056 atomic_inc(&md->holders);
1057}
1058
1059void dm_put(struct mapped_device *md)
1060{
1061 struct dm_table *map;
1062
1030
1031 return md;
1032}
1033
1034struct mapped_device *dm_get_md(dev_t dev)
1035{
1036 struct mapped_device *md = dm_find_md(dev);
1037

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1055{
1056 atomic_inc(&md->holders);
1057}
1058
1059void dm_put(struct mapped_device *md)
1060{
1061 struct dm_table *map;
1062
1063 if (atomic_dec_and_test(&md->holders)) {
1063 if (atomic_dec_and_lock(&md->holders, &_minor_lock)) {
1064 map = dm_get_table(md);
1064 map = dm_get_table(md);
1065 mutex_lock(&_minor_lock);
1066 idr_replace(&_minor_idr, MINOR_ALLOCED, dm_disk(md)->first_minor);
1065 idr_replace(&_minor_idr, MINOR_ALLOCED, dm_disk(md)->first_minor);
1067 mutex_unlock(&_minor_lock);
1066 spin_unlock(&_minor_lock);
1068 if (!dm_suspended(md)) {
1069 dm_table_presuspend_targets(map);
1070 dm_table_postsuspend_targets(map);
1071 }
1072 __unbind(md);
1073 dm_table_put(map);
1074 free_dev(md);
1075 }

--- 259 unchanged lines hidden --- 		1067 if (!dm_suspended(md)) {
1068 dm_table_presuspend_targets(map);
1069 dm_table_postsuspend_targets(map);
1070 }
1071 __unbind(md);
1072 dm_table_put(map);
1073 free_dev(md);
1074 }

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