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lvm2/lib/mm/memlock.h
Zdenek Kabelac 6365f011b0 locking: introduce prioritized_section
Introduce prioritized_section() as a closer match to previous logic
of critical_section() that has been held over longer sequence of
ioctl commands - essentially it's matching operation on a single
cookie.

While 'critical_section()' now corresponds to locked memory - we hold
this memory only between suspend/resume thus notion of 'cookie' was
lost.

This patch restores some logic unintentionaly lost with dropping
memory locking for just activation/deactivation calls.
2018-03-15 10:59:42 +01:00

46 lines
1.5 KiB
C

/*
* Copyright (C) 2001-2004 Sistina Software, Inc. All rights reserved.
* Copyright (C) 2004-2011 Red Hat, Inc. All rights reserved.
*
* This file is part of LVM2.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU Lesser General Public License v.2.1.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef LVM_MEMLOCK_H
#define LVM_MEMLOCK_H
struct cmd_context;
/*
* Inside a critical section, memory is always locked.
*
* After leaving the critical section, memory stays locked until
* memlock_unlock() is called. This happens with
* sync_local_dev_names() and sync_dev_names().
*
* This allows critical sections to be entered and exited repeatedly without
* incurring the expense of locking memory every time.
*
* memlock_reset() is necessary to clear the state after forking (polldaemon).
*/
void critical_section_inc(struct cmd_context *cmd, const char *reason);
void critical_section_dec(struct cmd_context *cmd, const char *reason);
int critical_section(void);
int prioritized_section(void);
void memlock_inc_daemon(struct cmd_context *cmd);
void memlock_dec_daemon(struct cmd_context *cmd);
int memlock_count_daemon(void);
void memlock_init(struct cmd_context *cmd);
void memlock_reset(void);
void memlock_unlock(struct cmd_context *cmd);
#endif