\*****************************************************************************/
#ifndef _SPL_RWLOCK_H
-#define _SPL_RWLOCK_H
+#define _SPL_RWLOCK_H
#include <sys/types.h>
#include <linux/rwsem.h>
#include <linux/rwsem_compat.h>
typedef enum {
- RW_DRIVER = 2,
- RW_DEFAULT = 4
+ RW_DRIVER = 2,
+ RW_DEFAULT = 4,
+ RW_NOLOCKDEP = 5
} krw_type_t;
typedef enum {
- RW_NONE = 0,
- RW_WRITER = 1,
- RW_READER = 2
+ RW_NONE = 0,
+ RW_WRITER = 1,
+ RW_READER = 2
} krw_t;
+/*
+ * If CONFIG_RWSEM_SPIN_ON_OWNER is defined, rw_semaphore will have an owner
+ * field, so we don't need our own.
+ */
typedef struct {
- struct rw_semaphore rw_rwlock;
- kthread_t *rw_owner;
+ struct rw_semaphore rw_rwlock;
+#ifndef CONFIG_RWSEM_SPIN_ON_OWNER
+ kthread_t *rw_owner;
+#endif
+#ifdef CONFIG_LOCKDEP
+ krw_type_t rw_type;
+#endif /* CONFIG_LOCKDEP */
} krwlock_t;
-#define SEM(rwp) ((struct rw_semaphore *)(rwp))
+#define SEM(rwp) (&(rwp)->rw_rwlock)
static inline void
spl_rw_set_owner(krwlock_t *rwp)
{
- unsigned long flags;
-
- spl_rwsem_lock_irqsave(&SEM(rwp)->wait_lock, flags);
- rwp->rw_owner = current;
- spl_rwsem_unlock_irqrestore(&SEM(rwp)->wait_lock, flags);
+/*
+ * If CONFIG_RWSEM_SPIN_ON_OWNER is defined, down_write, up_write,
+ * downgrade_write and __init_rwsem will set/clear owner for us.
+ */
+#ifndef CONFIG_RWSEM_SPIN_ON_OWNER
+ rwp->rw_owner = current;
+#endif
}
static inline void
spl_rw_clear_owner(krwlock_t *rwp)
{
- unsigned long flags;
-
- spl_rwsem_lock_irqsave(&SEM(rwp)->wait_lock, flags);
- rwp->rw_owner = NULL;
- spl_rwsem_unlock_irqrestore(&SEM(rwp)->wait_lock, flags);
+#ifndef CONFIG_RWSEM_SPIN_ON_OWNER
+ rwp->rw_owner = NULL;
+#endif
}
static inline kthread_t *
rw_owner(krwlock_t *rwp)
{
- unsigned long flags;
- kthread_t *owner;
-
- spl_rwsem_lock_irqsave(&SEM(rwp)->wait_lock, flags);
- owner = rwp->rw_owner;
- spl_rwsem_unlock_irqrestore(&SEM(rwp)->wait_lock, flags);
+#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
+ return (SEM(rwp)->owner);
+#else
+ return (rwp->rw_owner);
+#endif
+}
- return owner;
+#ifdef CONFIG_LOCKDEP
+static inline void
+spl_rw_set_type(krwlock_t *rwp, krw_type_t type)
+{
+ rwp->rw_type = type;
+}
+static inline void
+spl_rw_lockdep_off_maybe(krwlock_t *rwp) \
+{ \
+ if (rwp && rwp->rw_type == RW_NOLOCKDEP) \
+ lockdep_off(); \
+}
+static inline void
+spl_rw_lockdep_on_maybe(krwlock_t *rwp) \
+{ \
+ if (rwp && rwp->rw_type == RW_NOLOCKDEP) \
+ lockdep_on(); \
}
+#else /* CONFIG_LOCKDEP */
+#define spl_rw_set_type(rwp, type)
+#define spl_rw_lockdep_off_maybe(rwp)
+#define spl_rw_lockdep_on_maybe(rwp)
+#endif /* CONFIG_LOCKDEP */
static inline int
RW_READ_HELD(krwlock_t *rwp)
static inline int
RW_WRITE_HELD(krwlock_t *rwp)
{
- return (spl_rwsem_is_locked(SEM(rwp)) && rw_owner(rwp) == current);
+ return (rw_owner(rwp) == current);
}
static inline int
RW_LOCK_HELD(krwlock_t *rwp)
{
- return spl_rwsem_is_locked(SEM(rwp));
+ return (spl_rwsem_is_locked(SEM(rwp)));
}
/*
* will be correctly located in the users code which is important
* for the built in kernel lock analysis tools
*/
-#define rw_init(rwp, name, type, arg) \
-({ \
- static struct lock_class_key __key; \
- \
- __init_rwsem(SEM(rwp), #rwp, &__key); \
- spl_rw_clear_owner(rwp); \
+/* BEGIN CSTYLED */
+#define rw_init(rwp, name, type, arg) \
+({ \
+ static struct lock_class_key __key; \
+ ASSERT(type == RW_DEFAULT || type == RW_NOLOCKDEP); \
+ \
+ __init_rwsem(SEM(rwp), #rwp, &__key); \
+ spl_rw_clear_owner(rwp); \
+ spl_rw_set_type(rwp, type); \
})
-#define rw_destroy(rwp) \
-({ \
- VERIFY(!RW_LOCK_HELD(rwp)); \
-})
+/*
+ * The Linux rwsem implementation does not require a matching destroy.
+ */
+#define rw_destroy(rwp) ((void) 0)
-#define rw_tryenter(rwp, rw) \
-({ \
- int _rc_ = 0; \
- \
- switch (rw) { \
- case RW_READER: \
- _rc_ = down_read_trylock(SEM(rwp)); \
- break; \
- case RW_WRITER: \
- if ((_rc_ = down_write_trylock(SEM(rwp)))) \
- spl_rw_set_owner(rwp); \
- break; \
- default: \
- VERIFY(0); \
- } \
- _rc_; \
+#define rw_tryenter(rwp, rw) \
+({ \
+ int _rc_ = 0; \
+ \
+ spl_rw_lockdep_off_maybe(rwp); \
+ switch (rw) { \
+ case RW_READER: \
+ _rc_ = down_read_trylock(SEM(rwp)); \
+ break; \
+ case RW_WRITER: \
+ if ((_rc_ = down_write_trylock(SEM(rwp)))) \
+ spl_rw_set_owner(rwp); \
+ break; \
+ default: \
+ VERIFY(0); \
+ } \
+ spl_rw_lockdep_on_maybe(rwp); \
+ _rc_; \
})
-#define rw_enter(rwp, rw) \
-({ \
- switch (rw) { \
- case RW_READER: \
- down_read(SEM(rwp)); \
- break; \
- case RW_WRITER: \
- down_write(SEM(rwp)); \
- spl_rw_set_owner(rwp); \
- break; \
- default: \
- VERIFY(0); \
- } \
+#define rw_enter(rwp, rw) \
+({ \
+ spl_rw_lockdep_off_maybe(rwp); \
+ switch (rw) { \
+ case RW_READER: \
+ down_read(SEM(rwp)); \
+ break; \
+ case RW_WRITER: \
+ down_write(SEM(rwp)); \
+ spl_rw_set_owner(rwp); \
+ break; \
+ default: \
+ VERIFY(0); \
+ } \
+ spl_rw_lockdep_on_maybe(rwp); \
})
-#define rw_exit(rwp) \
-({ \
- if (RW_WRITE_HELD(rwp)) { \
- spl_rw_clear_owner(rwp); \
- up_write(SEM(rwp)); \
- } else { \
- ASSERT(RW_READ_HELD(rwp)); \
- up_read(SEM(rwp)); \
- } \
+#define rw_exit(rwp) \
+({ \
+ spl_rw_lockdep_off_maybe(rwp); \
+ if (RW_WRITE_HELD(rwp)) { \
+ spl_rw_clear_owner(rwp); \
+ up_write(SEM(rwp)); \
+ } else { \
+ ASSERT(RW_READ_HELD(rwp)); \
+ up_read(SEM(rwp)); \
+ } \
+ spl_rw_lockdep_on_maybe(rwp); \
})
-#define rw_downgrade(rwp) \
-({ \
- spl_rw_clear_owner(rwp); \
- downgrade_write(SEM(rwp)); \
+#define rw_downgrade(rwp) \
+({ \
+ spl_rw_lockdep_off_maybe(rwp); \
+ spl_rw_clear_owner(rwp); \
+ downgrade_write(SEM(rwp)); \
+ spl_rw_lockdep_on_maybe(rwp); \
})
-/*
- * This implementation of rw_tryupgrade() behaves slightly differently
- * from its counterparts on other platforms. It drops the RW_READER lock
- * and then acquires the RW_WRITER lock leaving a small window where no
- * lock is held. On other platforms the lock is never released during
- * the upgrade process. This is necessary under Linux because the kernel
- * does not provide an upgrade function.
- */
-#define rw_tryupgrade(rwp) \
+#define rw_tryupgrade(rwp) \
({ \
int _rc_ = 0; \
\
if (RW_WRITE_HELD(rwp)) { \
_rc_ = 1; \
} else { \
+ spl_rw_lockdep_off_maybe(rwp); \
if ((_rc_ = rwsem_tryupgrade(SEM(rwp)))) \
spl_rw_set_owner(rwp); \
+ spl_rw_lockdep_on_maybe(rwp); \
} \
_rc_; \
})
+/* END CSTYLED */
int spl_rw_init(void);
void spl_rw_fini(void);