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Add witness_upgrade() and witness_downgrade() for handling upgrades and

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downgrades of shared/exclusive locks.
This commit is contained in:
John Baldwin 2001-08-23 22:47:05 +00:00
parent d7c4536a55
commit c19fe5e261
2 changed files with 83 additions and 0 deletions
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71
sys/kern/subr_witness.c
View File

@ -348,6 +348,11 @@ witness_init(struct lock_object *lock)
panic("%s: lock (%s) %s can not be sleepable!\n", __func__,
class->lc_name, lock->lo_name);
if ((lock->lo_flags & LO_UPGRADABLE) != 0 &&
(class->lc_flags & LC_UPGRADABLE) == 0)
panic("%s: lock (%s) %s can not be upgradable!\n", __func__,
class->lc_name, lock->lo_name);
mtx_lock(&all_mtx);
STAILQ_INSERT_TAIL(&all_locks, lock, lo_list);
lock->lo_flags |= LO_INITIALIZED;
@ -712,6 +717,72 @@ witness_lock(struct lock_object *lock, int flags, const char *file, int line)
curproc->p_pid, lock->lo_name, lle->ll_count - 1);
}
void
witness_upgrade(struct lock_object *lock, int flags, const char *file, int line)
{
struct lock_instance *instance;
struct lock_class *class;
KASSERT(!witness_cold, ("%s: witness_cold\n", __func__));
if (lock->lo_witness == NULL || witness_dead || panicstr != NULL)
return;
class = lock->lo_class;
if ((lock->lo_flags & LO_UPGRADABLE) == 0)
panic("upgrade of non-upgradable lock (%s) %s @ %s:%d",
class->lc_name, lock->lo_name, file, line);
if ((flags & LOP_TRYLOCK) == 0)
panic("non-try upgrade of lock (%s) %s @ %s:%d", class->lc_name,
lock->lo_name, file, line);
if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0)
panic("upgrade of non-sleep lock (%s) %s @ %s:%d",
class->lc_name, lock->lo_name, file, line);
instance = find_instance(curproc->p_sleeplocks, lock);
if (instance == NULL)
panic("upgrade of unlocked lock (%s) %s @ %s:%d",
class->lc_name, lock->lo_name, file, line);
if ((instance->li_flags & LI_EXCLUSIVE) != 0)
panic("upgrade of exclusive lock (%s) %s @ %s:%d",
class->lc_name, lock->lo_name, file, line);
if ((instance->li_flags & LI_RECURSEMASK) != 0)
panic("upgrade of recursed lock (%s) %s r=%d @ %s:%d",
class->lc_name, lock->lo_name,
instance->li_flags & LI_RECURSEMASK, file, line);
instance->li_flags |= LI_EXCLUSIVE;
}
void
witness_downgrade(struct lock_object *lock, int flags, const char *file,
int line)
{
struct lock_instance *instance;
struct lock_class *class;
KASSERT(!witness_cold, ("%s: witness_cold\n", __func__));
if (lock->lo_witness == NULL || witness_dead || panicstr != NULL)
return;
class = lock->lo_class;
if ((lock->lo_flags & LO_UPGRADABLE) == 0)
panic("downgrade of non-upgradable lock (%s) %s @ %s:%d",
class->lc_name, lock->lo_name, file, line);
if ((lock->lo_class->lc_flags & LC_SLEEPLOCK) == 0)
panic("downgrade of non-sleep lock (%s) %s @ %s:%d",
class->lc_name, lock->lo_name, file, line);
instance = find_instance(curproc->p_sleeplocks, lock);
if (instance == NULL)
panic("downgrade of unlocked lock (%s) %s @ %s:%d",
class->lc_name, lock->lo_name, file, line);
if ((instance->li_flags & LI_EXCLUSIVE) == 0)
panic("downgrade of shared lock (%s) %s @ %s:%d",
class->lc_name, lock->lo_name, file, line);
if ((instance->li_flags & LI_RECURSEMASK) != 0)
panic("downgrade of recursed lock (%s) %s r=%d @ %s:%d",
class->lc_name, lock->lo_name,
instance->li_flags & LI_RECURSEMASK, file, line);
instance->li_flags &= ~LI_EXCLUSIVE;
}
void
witness_unlock(struct lock_object *lock, int flags, const char *file, int line)
{

12
sys/sys/lock.h
View File

@ -60,6 +60,7 @@ struct lock_class {
#define LC_SPINLOCK 0x00000002 /* Spin lock. */
#define LC_SLEEPABLE 0x00000004 /* Sleeping allowed with this lock. */
#define LC_RECURSABLE 0x00000008 /* Locks of this type may recurse. */
#define LC_UPGRADABLE 0x00000010 /* Upgrades and downgrades permitted. */
#define LO_CLASSFLAGS 0x0000ffff /* Class specific flags. */
#define LO_INITIALIZED 0x00010000 /* Lock has been initialized. */
@ -67,6 +68,7 @@ struct lock_class {
#define LO_QUIET 0x00040000 /* Don't log locking operations. */
#define LO_RECURSABLE 0x00080000 /* Lock may recurse. */
#define LO_SLEEPABLE 0x00100000 /* Lock may be held while sleeping. */
#define LO_UPGRADABLE 0x00200000 /* Lock may be upgraded/downgraded. */
#define LI_RECURSEMASK 0x0000ffff /* Recursion depth of lock instance. */
#define LI_SLEPT 0x00010000 /* Lock instance has been slept with. */
@ -174,6 +176,8 @@ extern struct lock_class lock_class_sx;
void witness_init(struct lock_object *);
void witness_destroy(struct lock_object *);
void witness_lock(struct lock_object *, int, const char *, int);
void witness_upgrade(struct lock_object *, int, const char *, int);
void witness_downgrade(struct lock_object *, int, const char *, int);
void witness_unlock(struct lock_object *, int, const char *, int);
void witness_save(struct lock_object *, const char **, int *);
void witness_restore(struct lock_object *, const char *, int);
@ -192,6 +196,12 @@ void witness_assert(struct lock_object *, int, const char *, int);
#define WITNESS_LOCK(lock, flags, file, line) \
witness_lock((lock), (flags), (file), (line))
#define WITNESS_UPGRADE(lock, flags, file, line) \
witness_upgrade((lock), (flags), (file), (line))
#define WITNESS_DOWNGRADE(lock, flags, file, line) \
witness_downgrade((lock), (flags), (file), (line))
#define WITNESS_UNLOCK(lock, flags, file, line) \
witness_unlock((lock), (flags), (file), (line))
@ -212,6 +222,8 @@ void witness_assert(struct lock_object *, int, const char *, int);
#define WITNESS_INIT(lock) (lock)->lo_flags |= LO_INITIALIZED
#define WITNESS_DESTROY(lock) (lock)->lo_flags &= ~LO_INITIALIZED
#define WITNESS_LOCK(lock, flags, file, line)
#define WITNESS_UPGRADE(lock, flags, file, line)
#define WITNESS_DOWNGRADE(lock, flags, file, line)
#define WITNESS_UNLOCK(lock, flags, file, line)
#define WITNESS_SLEEP(check, lock)
#define WITNESS_SAVE_DECL(n)