mirror of
https://github.com/FEX-Emu/linux.git
synced 2024-12-29 13:00:35 +00:00
72c93bcc63
init_rwsem() has no return value. This is not a problem if init_rwsem()
is a function, but it's a problem if it's a do { ... } while (0) macro.
(which lockdep introduces)
SGI-PV: 904196
SGI-Modid: xfs-linux-melb:xfs-kern:26082a
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Nathan Scott <nathans@sgi.com>
93 lines
2.3 KiB
C
93 lines
2.3 KiB
C
/*
|
|
* Copyright (c) 2000-2006 Silicon Graphics, Inc.
|
|
* All Rights Reserved.
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License as
|
|
* published by the Free Software Foundation.
|
|
*
|
|
* This program is distributed in the hope that it would be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with this program; if not, write the Free Software Foundation,
|
|
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
#ifndef __XFS_SUPPORT_MRLOCK_H__
|
|
#define __XFS_SUPPORT_MRLOCK_H__
|
|
|
|
#include <linux/rwsem.h>
|
|
|
|
enum { MR_NONE, MR_ACCESS, MR_UPDATE };
|
|
|
|
typedef struct {
|
|
struct rw_semaphore mr_lock;
|
|
int mr_writer;
|
|
} mrlock_t;
|
|
|
|
#define mrinit(mrp, name) \
|
|
do { (mrp)->mr_writer = 0; init_rwsem(&(mrp)->mr_lock); } while (0)
|
|
#define mrlock_init(mrp, t,n,s) mrinit(mrp, n)
|
|
#define mrfree(mrp) do { } while (0)
|
|
#define mraccess(mrp) mraccessf(mrp, 0)
|
|
#define mrupdate(mrp) mrupdatef(mrp, 0)
|
|
|
|
static inline void mraccessf(mrlock_t *mrp, int flags)
|
|
{
|
|
down_read(&mrp->mr_lock);
|
|
}
|
|
|
|
static inline void mrupdatef(mrlock_t *mrp, int flags)
|
|
{
|
|
down_write(&mrp->mr_lock);
|
|
mrp->mr_writer = 1;
|
|
}
|
|
|
|
static inline int mrtryaccess(mrlock_t *mrp)
|
|
{
|
|
return down_read_trylock(&mrp->mr_lock);
|
|
}
|
|
|
|
static inline int mrtryupdate(mrlock_t *mrp)
|
|
{
|
|
if (!down_write_trylock(&mrp->mr_lock))
|
|
return 0;
|
|
mrp->mr_writer = 1;
|
|
return 1;
|
|
}
|
|
|
|
static inline void mrunlock(mrlock_t *mrp)
|
|
{
|
|
if (mrp->mr_writer) {
|
|
mrp->mr_writer = 0;
|
|
up_write(&mrp->mr_lock);
|
|
} else {
|
|
up_read(&mrp->mr_lock);
|
|
}
|
|
}
|
|
|
|
static inline void mrdemote(mrlock_t *mrp)
|
|
{
|
|
mrp->mr_writer = 0;
|
|
downgrade_write(&mrp->mr_lock);
|
|
}
|
|
|
|
#ifdef DEBUG
|
|
/*
|
|
* Debug-only routine, without some platform-specific asm code, we can
|
|
* now only answer requests regarding whether we hold the lock for write
|
|
* (reader state is outside our visibility, we only track writer state).
|
|
* Note: means !ismrlocked would give false positives, so don't do that.
|
|
*/
|
|
static inline int ismrlocked(mrlock_t *mrp, int type)
|
|
{
|
|
if (mrp && type == MR_UPDATE)
|
|
return mrp->mr_writer;
|
|
return 1;
|
|
}
|
|
#endif
|
|
|
|
#endif /* __XFS_SUPPORT_MRLOCK_H__ */
|