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[XFS] shrink mrlock_t

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The writer field is not needed for non_DEBU builds so remove it. While
we're at i also clean up the interface for is locked asserts to go through
and xfs_iget.c helper with an interface like the xfs_ilock routines to
isolated the XFS codebase from mrlock internals. That way we can kill
mrlock_t entirely once rw_semaphores grow an islocked facility. Also
remove unused flags to the ilock family of functions.

SGI-PV: 976035
SGI-Modid: xfs-linux-melb:xfs-kern:30902a

Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>
This commit is contained in:
Christoph Hellwig
2008-04-22 17:34:00 +10:00
committed by Lachlan McIlroy
parent eca450b7c2
commit 579aa9caf5
15 changed files with 155 additions and 176 deletions
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60
fs/xfs/linux-2.6/mrlock.h
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@@ -20,29 +20,24 @@
#include <linux/rwsem.h>
enum { MR_NONE, MR_ACCESS, MR_UPDATE };
typedef struct {
struct rw_semaphore mr_lock;
#ifdef DEBUG
int mr_writer;
#endif
} mrlock_t;
#ifdef DEBUG
#define mrinit(mrp, name) \
do { (mrp)->mr_writer = 0; init_rwsem(&(mrp)->mr_lock); } while (0)
#else
#define mrinit(mrp, name) \
do { init_rwsem(&(mrp)->mr_lock); } while (0)
#endif
#define mrlock_init(mrp, t,n,s) mrinit(mrp, n)
#define mrfree(mrp) do { } while (0)
static inline void mraccess(mrlock_t *mrp)
{
down_read(&mrp->mr_lock);
}
static inline void mrupdate(mrlock_t *mrp)
{
down_write(&mrp->mr_lock);
mrp->mr_writer = 1;
}
static inline void mraccess_nested(mrlock_t *mrp, int subclass)
{
down_read_nested(&mrp->mr_lock, subclass);
@@ -51,10 +46,11 @@ static inline void mraccess_nested(mrlock_t *mrp, int subclass)
static inline void mrupdate_nested(mrlock_t *mrp, int subclass)
{
down_write_nested(&mrp->mr_lock, subclass);
#ifdef DEBUG
mrp->mr_writer = 1;
#endif
}
static inline int mrtryaccess(mrlock_t *mrp)
{
return down_read_trylock(&mrp->mr_lock);
@@ -64,39 +60,31 @@ static inline int mrtryupdate(mrlock_t *mrp)
{
if (!down_write_trylock(&mrp->mr_lock))
return 0;
#ifdef DEBUG
mrp->mr_writer = 1;
#endif
return 1;
}
static inline void mrunlock(mrlock_t *mrp)
static inline void mrunlock_excl(mrlock_t *mrp)
{
if (mrp->mr_writer) {
mrp->mr_writer = 0;
up_write(&mrp->mr_lock);
} else {
up_read(&mrp->mr_lock);
}
#ifdef DEBUG
mrp->mr_writer = 0;
#endif
up_write(&mrp->mr_lock);
}
static inline void mrunlock_shared(mrlock_t *mrp)
{
up_read(&mrp->mr_lock);
}
static inline void mrdemote(mrlock_t *mrp)
{
#ifdef DEBUG
mrp->mr_writer = 0;
#endif
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__ */