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- Updated rwlock's to reside in a .c file instead of a static inline 

- Updated rwlock's so they can be safely initialized in ctors.



git-svn-id: https://outreach.scidac.gov/svn/spl/trunk@96 7e1ea52c-4ff2-0310-8f11-9dd32ca42a1c
This commit is contained in:
behlendo 2008-05-06 23:00:49 +00:00
parent d6a26c6a32
commit e8b31e8482
3 changed files with 320 additions and 282 deletions
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10
include/sys/mutex.h
View File

@ -68,20 +68,12 @@ extern kthread_t *__spl_mutex_owner(kmutex_t *mp);
#define mutex_init(mp, name, type, ibc) \
({ \
__ENTRY(S_MUTEX); \
if ((name) == NULL) \
__spl_mutex_init(mp, #mp, type, ibc); \
else \
__spl_mutex_init(mp, name, type, ibc); \
__EXIT(S_MUTEX); \
})
#define mutex_destroy(mp) \
({ \
__ENTRY(S_MUTEX); \
__spl_mutex_destroy(mp); \
__EXIT(S_MUTEX); \
})
#define mutex_destroy(mp) __spl_mutex_destroy(mp)
#define mutex_tryenter(mp) __mutex_tryenter(mp)
#define mutex_enter(mp) __mutex_enter(mp)
#define mutex_exit(mp) __mutex_exit(mp)

305
include/sys/rwlock.h
View File

@ -1,13 +1,14 @@
#ifndef _SPL_RWLOCK_H
#define _SPL_RWLOCK_H
#define _SPL_RWLOCK_H
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/rwsem.h>
#include <asm/current.h>
#include <sys/types.h>
#include <sys/kmem.h>
#ifdef __cplusplus
#ifdef __cplusplus
extern "C" {
#endif
@ -21,292 +22,50 @@ typedef enum {
RW_READER
} krw_t;
#define RW_READ_HELD(x) (__rw_read_held((x)))
#define RW_WRITE_HELD(x) (__rw_write_held((x)))
#define RW_LOCK_HELD(x) (__rw_lock_held((x)))
#define RW_ISWRITER(x) (__rw_iswriter(x))
#define RW_MAGIC 0x3423645a
#define RW_POISON 0xa6
typedef struct {
int rw_magic;
int32_t rw_magic;
int32_t rw_name_size;
char *rw_name;
struct rw_semaphore rw_sem;
struct task_struct *rw_owner; /* holder of the write lock */
} krwlock_t;
#ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
struct rwsem_waiter {
struct list_head list;
struct task_struct *task;
unsigned int flags;
#define RWSEM_WAITING_FOR_READ 0x00000001
#define RWSEM_WAITING_FOR_WRITE 0x00000002
};
/*
* wake a single writer
*/
static inline struct rw_semaphore *
__rwsem_wake_one_writer_locked(struct rw_semaphore *sem)
{
struct rwsem_waiter *waiter;
struct task_struct *tsk;
sem->activity = -1;
waiter = list_entry(sem->wait_list.next, struct rwsem_waiter, list);
list_del(&waiter->list);
tsk = waiter->task;
smp_mb();
waiter->task = NULL;
wake_up_process(tsk);
put_task_struct(tsk);
return sem;
}
/*
* release a read lock on the semaphore
*/
static void fastcall
__up_read_locked(struct rw_semaphore *sem)
{
if (--sem->activity == 0 && !list_empty(&sem->wait_list))
sem = __rwsem_wake_one_writer_locked(sem);
}
/*
* trylock for writing -- returns 1 if successful, 0 if contention
*/
static int fastcall
__down_write_trylock_locked(struct rw_semaphore *sem)
{
int ret = 0;
if (sem->activity == 0 && list_empty(&sem->wait_list)) {
/* granted */
sem->activity = -1;
ret = 1;
}
return ret;
}
#endif
extern void __rw_init(krwlock_t *rwlp, char *name, krw_type_t type, void *arg);
extern void __rw_destroy(krwlock_t *rwlp);
extern int __rw_tryenter(krwlock_t *rwlp, krw_t rw);
extern void __rw_enter(krwlock_t *rwlp, krw_t rw);
extern void __rw_exit(krwlock_t *rwlp);
extern void __rw_downgrade(krwlock_t *rwlp);
extern int __rw_tryupgrade(krwlock_t *rwlp);
extern kthread_t *__rw_owner(krwlock_t *rwlp);
extern int __rw_read_held(krwlock_t *rwlp);
extern int __rw_write_held(krwlock_t *rwlp);
extern int __rw_lock_held(krwlock_t *rwlp);
static __inline__ void
rw_init(krwlock_t *rwlp, char *name, krw_type_t type, void *arg)
{
ASSERT(type == RW_DEFAULT); /* XXX no irq handler use */
ASSERT(arg == NULL); /* XXX no irq handler use */
#define rw_init(rwlp, name, type, arg) \
({ \
if ((name) == NULL) \
__rw_init(rwlp, #rwlp, type, arg); \
else \
__rw_init(rwlp, name, type, arg); \
})
#define rw_destroy(rwlp) __rw_destroy(rwlp)
#define rw_tryenter(rwlp, rw) __rw_tryenter(rwlp, rw)
#define rw_enter(rwlp, rw) __rw_enter(rwlp, rw)
#define rw_exit(rwlp) __rw_exit(rwlp)
#define rw_downgrade(rwlp) __rw_downgrade(rwlp)
#define rw_tryupgrade(rwlp) __rw_tryupgrade(rwlp)
#define rw_owner(rwlp) __rw_owner(rwlp)
#define RW_READ_HELD(rwlp) __rw_read_held(rwlp)
#define RW_WRITE_HELD(rwlp) __rw_write_held(rwlp)
#define RW_LOCK_HELD(rwlp) __rw_lock_held(rwlp)
rwlp->rw_magic = RW_MAGIC;
rwlp->rw_owner = NULL; /* no one holds the write lock yet */
init_rwsem(&rwlp->rw_sem);
rwlp->rw_name = NULL;
if (name) {
rwlp->rw_name = kmalloc(strlen(name) + 1, GFP_KERNEL);
if (rwlp->rw_name)
strcpy(rwlp->rw_name, name);
}
}
static __inline__ void
rw_destroy(krwlock_t *rwlp)
{
ASSERT(rwlp);
ASSERT(rwlp->rw_magic == RW_MAGIC);
ASSERT(rwlp->rw_owner == NULL);
spin_lock(&rwlp->rw_sem.wait_lock);
ASSERT(list_empty(&rwlp->rw_sem.wait_list));
spin_unlock(&rwlp->rw_sem.wait_lock);
if (rwlp->rw_name)
kfree(rwlp->rw_name);
memset(rwlp, RW_POISON, sizeof(krwlock_t));
}
/* Return 0 if the lock could not be obtained without blocking.
*/
static __inline__ int
rw_tryenter(krwlock_t *rwlp, krw_t rw)
{
int result;
ASSERT(rwlp);
ASSERT(rwlp->rw_magic == RW_MAGIC);
switch (rw) {
/* these functions return 1 if success, 0 if contention */
case RW_READER:
/* Here the Solaris code would return 0
* if there were any write waiters. Specifically
* thinking about the case where readers may have
* the lock and we would also allow this thread
* to grab the read lock with a writer waiting in the
* queue. This doesn't seem like a correctness
* issue, so just call down_read_trylock()
* for the test. We may have to revisit this if
* it becomes an issue */
result = down_read_trylock(&rwlp->rw_sem);
break;
case RW_WRITER:
result = down_write_trylock(&rwlp->rw_sem);
if (result) {
/* there better not be anyone else
* holding the write lock here */
ASSERT(rwlp->rw_owner == NULL);
rwlp->rw_owner = current;
}
break;
default:
SBUG();
}
return result;
}
static __inline__ void
rw_enter(krwlock_t *rwlp, krw_t rw)
{
ASSERT(rwlp);
ASSERT(rwlp->rw_magic == RW_MAGIC);
switch (rw) {
case RW_READER:
/* Here the Solaris code would block
* if there were any write waiters. Specifically
* thinking about the case where readers may have
* the lock and we would also allow this thread
* to grab the read lock with a writer waiting in the
* queue. This doesn't seem like a correctness
* issue, so just call down_read()
* for the test. We may have to revisit this if
* it becomes an issue */
down_read(&rwlp->rw_sem);
break;
case RW_WRITER:
down_write(&rwlp->rw_sem);
/* there better not be anyone else
* holding the write lock here */
ASSERT(rwlp->rw_owner == NULL);
rwlp->rw_owner = current;
break;
default:
SBUG();
}
}
static __inline__ void
rw_exit(krwlock_t *rwlp)
{
ASSERT(rwlp);
ASSERT(rwlp->rw_magic == RW_MAGIC);
/* rw_owner is held by current
* thread iff it is a writer */
if (rwlp->rw_owner == current) {
rwlp->rw_owner = NULL;
up_write(&rwlp->rw_sem);
} else {
up_read(&rwlp->rw_sem);
}
}
static __inline__ void
rw_downgrade(krwlock_t *rwlp)
{
ASSERT(rwlp);
ASSERT(rwlp->rw_magic == RW_MAGIC);
ASSERT(rwlp->rw_owner == current);
rwlp->rw_owner = NULL;
downgrade_write(&rwlp->rw_sem);
}
/* Return 0 if unable to perform the upgrade.
* Might be wise to fix the caller
* to acquire the write lock first?
*/
static __inline__ int
rw_tryupgrade(krwlock_t *rwlp)
{
int result = 0;
ASSERT(rwlp);
ASSERT(rwlp->rw_magic == RW_MAGIC);
spin_lock(&rwlp->rw_sem.wait_lock);
/* Check if there is anyone waiting for the
* lock. If there is, then we know we should
* not try to upgrade the lock */
if (!list_empty(&rwlp->rw_sem.wait_list)) {
spin_unlock(&rwlp->rw_sem.wait_lock);
return 0;
}
#ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
/* Note that activity is protected by
* the wait_lock. Don't try to upgrade
* if there are multiple readers currently
* holding the lock */
if (rwlp->rw_sem.activity > 1) {
#else
/* Don't try to upgrade
* if there are multiple readers currently
* holding the lock */
if ((rwlp->rw_sem.count & RWSEM_ACTIVE_MASK) > 1) {
#endif
spin_unlock(&rwlp->rw_sem.wait_lock);
return 0;
}
#ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
/* Here it should be safe to drop the
* read lock and reacquire it for writing since
* we know there are no waiters */
__up_read_locked(&rwlp->rw_sem);
/* returns 1 if success, 0 if contention */
result = __down_write_trylock_locked(&rwlp->rw_sem);
#else
/* Here it should be safe to drop the
* read lock and reacquire it for writing since
* we know there are no waiters */
up_read(&rwlp->rw_sem);
/* returns 1 if success, 0 if contention */
result = down_write_trylock(&rwlp->rw_sem);
#endif
/* Check if upgrade failed. Should not ever happen
* if we got to this point */
ASSERT(result);
ASSERT(rwlp->rw_owner == NULL);
rwlp->rw_owner = current;
spin_unlock(&rwlp->rw_sem.wait_lock);
return 1;
}
static __inline__ kthread_t *
rw_owner(krwlock_t *rwlp)
{
ASSERT(rwlp);
ASSERT(rwlp->rw_magic == RW_MAGIC);
return rwlp->rw_owner;
}
#ifdef __cplusplus
#ifdef __cplusplus
}
#endif
#endif /* _SPL_RWLOCK_H */
#endif /* _SPL_RWLOCK_H */

287
modules/spl/spl-rwlock.c
View File

@ -6,10 +6,295 @@
#define DEBUG_SUBSYSTEM S_RWLOCK
#ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
struct rwsem_waiter {
struct list_head list;
struct task_struct *task;
unsigned int flags;
#define RWSEM_WAITING_FOR_READ 0x00000001
#define RWSEM_WAITING_FOR_WRITE 0x00000002
};
/* wake a single writer */
static struct rw_semaphore *
__rwsem_wake_one_writer_locked(struct rw_semaphore *sem)
{
struct rwsem_waiter *waiter;
struct task_struct *tsk;
sem->activity = -1;
waiter = list_entry(sem->wait_list.next, struct rwsem_waiter, list);
list_del(&waiter->list);
tsk = waiter->task;
smp_mb();
waiter->task = NULL;
wake_up_process(tsk);
put_task_struct(tsk);
return sem;
}
/* release a read lock on the semaphore */
static void
__up_read_locked(struct rw_semaphore *sem)
{
if (--sem->activity == 0 && !list_empty(&sem->wait_list))
sem = __rwsem_wake_one_writer_locked(sem);
}
/* trylock for writing -- returns 1 if successful, 0 if contention */
static int
__down_write_trylock_locked(struct rw_semaphore *sem)
{
int ret = 0;
if (sem->activity == 0 && list_empty(&sem->wait_list)) {
/* granted */
sem->activity = -1;
ret = 1;
}
return ret;
}
#endif
void
__rw_init(krwlock_t *rwlp, char *name, krw_type_t type, void *arg)
{
int flags = KM_SLEEP;
ASSERT(rwlp);
ASSERT(name);
ASSERT(type == RW_DEFAULT); /* XXX no irq handler use */
ASSERT(arg == NULL); /* XXX no irq handler use */
rwlp->rw_magic = RW_MAGIC;
rwlp->rw_owner = NULL;
rwlp->rw_name = NULL;
rwlp->rw_name_size = strlen(name) + 1;
/* We may be called when there is a non-zero preempt_count or
* interrupts are disabled is which case we must not sleep.
*/
if (current_thread_info()->preempt_count || irqs_disabled())
flags = KM_NOSLEEP;
rwlp->rw_name = kmem_alloc(rwlp->rw_name_size, flags);
if (rwlp->rw_name == NULL)
return;
init_rwsem(&rwlp->rw_sem);
strcpy(rwlp->rw_name, name);
}
EXPORT_SYMBOL(__rw_init);
void
__rw_destroy(krwlock_t *rwlp)
{
ASSERT(rwlp);
ASSERT(rwlp->rw_magic == RW_MAGIC);
ASSERT(rwlp->rw_owner == NULL);
spin_lock(&rwlp->rw_sem.wait_lock);
ASSERT(list_empty(&rwlp->rw_sem.wait_list));
spin_unlock(&rwlp->rw_sem.wait_lock);
kmem_free(rwlp->rw_name, rwlp->rw_name_size);
memset(rwlp, RW_POISON, sizeof(krwlock_t));
}
EXPORT_SYMBOL(__rw_destroy);
/* Return 0 if the lock could not be obtained without blocking. */
int
__rw_tryenter(krwlock_t *rwlp, krw_t rw)
{
int rc = 0;
ENTRY;
ASSERT(rwlp);
ASSERT(rwlp->rw_magic == RW_MAGIC);
switch (rw) {
/* these functions return 1 if success, 0 if contention */
case RW_READER:
/* Here the Solaris code would return 0
* if there were any write waiters. Specifically
* thinking about the case where readers may have
* the lock and we would also allow this thread
* to grab the read lock with a writer waiting in the
* queue. This doesn't seem like a correctness
* issue, so just call down_read_trylock()
* for the test. We may have to revisit this if
* it becomes an issue */
rc = down_read_trylock(&rwlp->rw_sem);
break;
case RW_WRITER:
rc = down_write_trylock(&rwlp->rw_sem);
if (rc) {
/* there better not be anyone else
* holding the write lock here */
ASSERT(rwlp->rw_owner == NULL);
rwlp->rw_owner = current;
}
break;
default:
SBUG();
}
RETURN(rc);
}
EXPORT_SYMBOL(__rw_tryenter);
void
__rw_enter(krwlock_t *rwlp, krw_t rw)
{
ENTRY;
ASSERT(rwlp);
ASSERT(rwlp->rw_magic == RW_MAGIC);
switch (rw) {
case RW_READER:
/* Here the Solaris code would block
* if there were any write waiters. Specifically
* thinking about the case where readers may have
* the lock and we would also allow this thread
* to grab the read lock with a writer waiting in the
* queue. This doesn't seem like a correctness
* issue, so just call down_read()
* for the test. We may have to revisit this if
* it becomes an issue */
down_read(&rwlp->rw_sem);
break;
case RW_WRITER:
down_write(&rwlp->rw_sem);
/* there better not be anyone else
* holding the write lock here */
ASSERT(rwlp->rw_owner == NULL);
rwlp->rw_owner = current;
break;
default:
SBUG();
}
EXIT;
}
EXPORT_SYMBOL(__rw_enter);
void
__rw_exit(krwlock_t *rwlp)
{
ENTRY;
ASSERT(rwlp);
ASSERT(rwlp->rw_magic == RW_MAGIC);
/* rw_owner is held by current
* thread iff it is a writer */
if (rwlp->rw_owner == current) {
rwlp->rw_owner = NULL;
up_write(&rwlp->rw_sem);
} else {
up_read(&rwlp->rw_sem);
}
EXIT;
}
EXPORT_SYMBOL(__rw_exit);
void
__rw_downgrade(krwlock_t *rwlp)
{
ENTRY;
ASSERT(rwlp);
ASSERT(rwlp->rw_magic == RW_MAGIC);
ASSERT(rwlp->rw_owner == current);
rwlp->rw_owner = NULL;
downgrade_write(&rwlp->rw_sem);
EXIT;
}
EXPORT_SYMBOL(__rw_downgrade);
/* Return 0 if unable to perform the upgrade.
* Might be wise to fix the caller
* to acquire the write lock first?
*/
int
__rw_tryupgrade(krwlock_t *rwlp)
{
int rc = 0;
ENTRY;
ASSERT(rwlp);
ASSERT(rwlp->rw_magic == RW_MAGIC);
spin_lock(&rwlp->rw_sem.wait_lock);
/* Check if there is anyone waiting for the
* lock. If there is, then we know we should
* not try to upgrade the lock */
if (!list_empty(&rwlp->rw_sem.wait_list)) {
spin_unlock(&rwlp->rw_sem.wait_lock);
RETURN(0);
}
#ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
/* Note that activity is protected by
* the wait_lock. Don't try to upgrade
* if there are multiple readers currently
* holding the lock */
if (rwlp->rw_sem.activity > 1) {
#else
/* Don't try to upgrade
* if there are multiple readers currently
* holding the lock */
if ((rwlp->rw_sem.count & RWSEM_ACTIVE_MASK) > 1) {
#endif
spin_unlock(&rwlp->rw_sem.wait_lock);
RETURN(0);
}
#ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
/* Here it should be safe to drop the
* read lock and reacquire it for writing since
* we know there are no waiters */
__up_read_locked(&rwlp->rw_sem);
/* returns 1 if success, 0 if contention */
rc = __down_write_trylock_locked(&rwlp->rw_sem);
#else
/* Here it should be safe to drop the
* read lock and reacquire it for writing since
* we know there are no waiters */
up_read(&rwlp->rw_sem);
/* returns 1 if success, 0 if contention */
rc = down_write_trylock(&rwlp->rw_sem);
#endif
/* Check if upgrade failed. Should not ever happen
* if we got to this point */
ASSERT(rc);
ASSERT(rwlp->rw_owner == NULL);
rwlp->rw_owner = current;
spin_unlock(&rwlp->rw_sem.wait_lock);
RETURN(1);
}
EXPORT_SYMBOL(__rw_tryupgrade);
kthread_t *
__rw_owner(krwlock_t *rwlp)
{
ENTRY;
ASSERT(rwlp);
ASSERT(rwlp->rw_magic == RW_MAGIC);
RETURN(rwlp->rw_owner);
}
EXPORT_SYMBOL(__rw_owner);
int
__rw_read_held(krwlock_t *rwlp)
{
ENTRY;
ASSERT(rwlp);
ASSERT(rwlp->rw_magic == RW_MAGIC);
RETURN(__rw_lock_held(rwlp) && rwlp->rw_owner == NULL);
}
@ -19,6 +304,7 @@ int
__rw_write_held(krwlock_t *rwlp)
{
ENTRY;
ASSERT(rwlp);
ASSERT(rwlp->rw_magic == RW_MAGIC);
RETURN(rwlp->rw_owner == current);
}
@ -30,6 +316,7 @@ __rw_lock_held(krwlock_t *rwlp)
int rc = 0;
ENTRY;
ASSERT(rwlp);
ASSERT(rwlp->rw_magic == RW_MAGIC);
spin_lock_irq(&(rwlp->rw_sem.wait_lock));