Revision ca0bf64d99f6e3f6e2fe2585e52a0ac57354beac authored by Thadeu Lima de Souza Cascardo on 02 February 2010, 21:44:17 UTC, committed by Linus Torvalds on 03 February 2010, 02:11:23 UTC
This is the counterpart to cba767175becadc5c4016cceb7bfdd2c7fe722f4 ("pktcdvd: remove broken dev_t export of class devices"). Device is not registered using dev_t, so it should not be destroyed using device_destroy which looks up the device by dev_t. This will fail and adding the device again will fail with the "duplicate name" error. This is fixed using device_unregister instead of device_destroy. Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Cc: Peter Osterlund <petero2@telia.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Jens Axboe <jens.axboe@oracle.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent ea08541
rwsem.c
/* kernel/rwsem.c: R/W semaphores, public implementation
*
* Written by David Howells (dhowells@redhat.com).
* Derived from asm-i386/semaphore.h
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/rwsem.h>
#include <asm/system.h>
#include <asm/atomic.h>
/*
* lock for reading
*/
void __sched down_read(struct rw_semaphore *sem)
{
might_sleep();
rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_);
LOCK_CONTENDED(sem, __down_read_trylock, __down_read);
}
EXPORT_SYMBOL(down_read);
/*
* trylock for reading -- returns 1 if successful, 0 if contention
*/
int down_read_trylock(struct rw_semaphore *sem)
{
int ret = __down_read_trylock(sem);
if (ret == 1)
rwsem_acquire_read(&sem->dep_map, 0, 1, _RET_IP_);
return ret;
}
EXPORT_SYMBOL(down_read_trylock);
/*
* lock for writing
*/
void __sched down_write(struct rw_semaphore *sem)
{
might_sleep();
rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_);
LOCK_CONTENDED(sem, __down_write_trylock, __down_write);
}
EXPORT_SYMBOL(down_write);
/*
* trylock for writing -- returns 1 if successful, 0 if contention
*/
int down_write_trylock(struct rw_semaphore *sem)
{
int ret = __down_write_trylock(sem);
if (ret == 1)
rwsem_acquire(&sem->dep_map, 0, 1, _RET_IP_);
return ret;
}
EXPORT_SYMBOL(down_write_trylock);
/*
* release a read lock
*/
void up_read(struct rw_semaphore *sem)
{
rwsem_release(&sem->dep_map, 1, _RET_IP_);
__up_read(sem);
}
EXPORT_SYMBOL(up_read);
/*
* release a write lock
*/
void up_write(struct rw_semaphore *sem)
{
rwsem_release(&sem->dep_map, 1, _RET_IP_);
__up_write(sem);
}
EXPORT_SYMBOL(up_write);
/*
* downgrade write lock to read lock
*/
void downgrade_write(struct rw_semaphore *sem)
{
/*
* lockdep: a downgraded write will live on as a write
* dependency.
*/
__downgrade_write(sem);
}
EXPORT_SYMBOL(downgrade_write);
#ifdef CONFIG_DEBUG_LOCK_ALLOC
void down_read_nested(struct rw_semaphore *sem, int subclass)
{
might_sleep();
rwsem_acquire_read(&sem->dep_map, subclass, 0, _RET_IP_);
LOCK_CONTENDED(sem, __down_read_trylock, __down_read);
}
EXPORT_SYMBOL(down_read_nested);
void down_read_non_owner(struct rw_semaphore *sem)
{
might_sleep();
__down_read(sem);
}
EXPORT_SYMBOL(down_read_non_owner);
void down_write_nested(struct rw_semaphore *sem, int subclass)
{
might_sleep();
rwsem_acquire(&sem->dep_map, subclass, 0, _RET_IP_);
LOCK_CONTENDED(sem, __down_write_trylock, __down_write);
}
EXPORT_SYMBOL(down_write_nested);
void up_read_non_owner(struct rw_semaphore *sem)
{
__up_read(sem);
}
EXPORT_SYMBOL(up_read_non_owner);
#endif
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