cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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snapshot.c (1621B)

      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);