1// SPDX-License-Identifier: GPL-2.0-only
 2/*
 3 * snapshot.c    Ceph snapshot context utility routines (part of libceph)
 4 *
 5 * Copyright (C) 2013 Inktank Storage, Inc.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 6 */
 7
 
 
 8#include <linux/types.h>
 9#include <linux/export.h>
10#include <linux/ceph/libceph.h>
11
12/*
13 * Ceph snapshot contexts are reference counted objects, and the
14 * returned structure holds a single reference.  Acquire additional
15 * references with ceph_get_snap_context(), and release them with
16 * ceph_put_snap_context().  When the reference count reaches zero
17 * the entire structure is freed.
18 */
19
20/*
21 * Create a new ceph snapshot context large enough to hold the
22 * indicated number of snapshot ids (which can be 0).  Caller has
23 * to fill in snapc->seq and snapc->snaps[0..snap_count-1].
24 *
25 * Returns a null pointer if an error occurs.
26 */
27struct ceph_snap_context *ceph_create_snap_context(u32 snap_count,
28						gfp_t gfp_flags)
29{
30	struct ceph_snap_context *snapc;
31	size_t size;
32
33	size = sizeof (struct ceph_snap_context);
34	size += snap_count * sizeof (snapc->snaps[0]);
35	snapc = kzalloc(size, gfp_flags);
36	if (!snapc)
37		return NULL;
38
39	refcount_set(&snapc->nref, 1);
40	snapc->num_snaps = snap_count;
41
42	return snapc;
43}
44EXPORT_SYMBOL(ceph_create_snap_context);
45
46struct ceph_snap_context *ceph_get_snap_context(struct ceph_snap_context *sc)
47{
48	if (sc)
49		refcount_inc(&sc->nref);
50	return sc;
51}
52EXPORT_SYMBOL(ceph_get_snap_context);
53
54void ceph_put_snap_context(struct ceph_snap_context *sc)
55{
56	if (!sc)
57		return;
58	if (refcount_dec_and_test(&sc->nref)) {
59		/*printk(" deleting snap_context %p\n", sc);*/
60		kfree(sc);
61	}
62}
63EXPORT_SYMBOL(ceph_put_snap_context);

 
 1/*
 2 * snapshot.c    Ceph snapshot context utility routines (part of libceph)
 3 *
 4 * Copyright (C) 2013 Inktank Storage, Inc.
 5 *
 6 * This program is free software; you can redistribute it and/or
 7 * modify it under the terms of the GNU General Public License
 8 * version 2 as published by the Free Software Foundation.
 9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
13 * General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
18 * 02110-1301, USA.
19 */
20
21#include <stddef.h>
22
23#include <linux/types.h>
24#include <linux/export.h>
25#include <linux/ceph/libceph.h>
26
27/*
28 * Ceph snapshot contexts are reference counted objects, and the
29 * returned structure holds a single reference.  Acquire additional
30 * references with ceph_get_snap_context(), and release them with
31 * ceph_put_snap_context().  When the reference count reaches zero
32 * the entire structure is freed.
33 */
34
35/*
36 * Create a new ceph snapshot context large enough to hold the
37 * indicated number of snapshot ids (which can be 0).  Caller has
38 * to fill in snapc->seq and snapc->snaps[0..snap_count-1].
39 *
40 * Returns a null pointer if an error occurs.
41 */
42struct ceph_snap_context *ceph_create_snap_context(u32 snap_count,
43						gfp_t gfp_flags)
44{
45	struct ceph_snap_context *snapc;
46	size_t size;
47
48	size = sizeof (struct ceph_snap_context);
49	size += snap_count * sizeof (snapc->snaps[0]);
50	snapc = kzalloc(size, gfp_flags);
51	if (!snapc)
52		return NULL;
53
54	atomic_set(&snapc->nref, 1);
55	snapc->num_snaps = snap_count;
56
57	return snapc;
58}
59EXPORT_SYMBOL(ceph_create_snap_context);
60
61struct ceph_snap_context *ceph_get_snap_context(struct ceph_snap_context *sc)
62{
63	if (sc)
64		atomic_inc(&sc->nref);
65	return sc;
66}
67EXPORT_SYMBOL(ceph_get_snap_context);
68
69void ceph_put_snap_context(struct ceph_snap_context *sc)
70{
71	if (!sc)
72		return;
73	if (atomic_dec_and_test(&sc->nref)) {
74		/*printk(" deleting snap_context %p\n", sc);*/
75		kfree(sc);
76	}
77}
78EXPORT_SYMBOL(ceph_put_snap_context);