/* kernel/rwsem.c: R/W semaphores, public implementation * * Written by David Howells (dhowells@redhat.com). * Derived from asm-i386/semaphore.h */ #include #include #include #include #include #include #include "rwsem.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); rwsem_set_reader_owned(sem); } 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_); rwsem_set_reader_owned(sem); } 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); rwsem_set_owner(sem); } EXPORT_SYMBOL(down_write); /* * lock for writing */ int __sched down_write_killable(struct rw_semaphore *sem) { might_sleep(); rwsem_acquire(&sem->dep_map, 0, 0, _RET_IP_); if (LOCK_CONTENDED_RETURN(sem, __down_write_trylock, __down_write_killable)) { rwsem_release(&sem->dep_map, 1, _RET_IP_); return -EINTR; } rwsem_set_owner(sem); return 0; } EXPORT_SYMBOL(down_write_killable); /* * 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_); rwsem_set_owner(sem); } 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_); rwsem_clear_owner(sem); __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. */ rwsem_set_reader_owned(sem); __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); rwsem_set_reader_owned(sem); } EXPORT_SYMBOL(down_read_nested); void _down_write_nest_lock(struct rw_semaphore *sem, struct lockdep_map *nest) { might_sleep(); rwsem_acquire_nest(&sem->dep_map, 0, 0, nest, _RET_IP_); LOCK_CONTENDED(sem, __down_write_trylock, __down_write); rwsem_set_owner(sem); } EXPORT_SYMBOL(_down_write_nest_lock); 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); rwsem_set_owner(sem); } EXPORT_SYMBOL(down_write_nested); int __sched down_write_killable_nested(struct rw_semaphore *sem, int subclass) { might_sleep(); rwsem_acquire(&sem->dep_map, subclass, 0, _RET_IP_); if (LOCK_CONTENDED_RETURN(sem, __down_write_trylock, __down_write_killable)) { rwsem_release(&sem->dep_map, 1, _RET_IP_); return -EINTR; } rwsem_set_owner(sem); return 0; } EXPORT_SYMBOL(down_write_killable_nested); void up_read_non_owner(struct rw_semaphore *sem) { __up_read(sem); } EXPORT_SYMBOL(up_read_non_owner); #endif 2'/>context:space:mode:
authorzhong jiang <zhongjiang@huawei.com>2017-01-24 15:18:52 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2017-01-24 16:26:14 -0800
commit3277953de2f31dd03c6375e9a9f680ac37fc9d27 (patch)
tree6ba22924faa1b82ef2f0277db10a3f5abdc44157 /include/trace/events/spi.h
parent3705ccfdd1e8b539225ce20e3925a945cc788d67 (diff)
mm: do not export ioremap_page_range symbol for external module
Recently, I've found cases in which ioremap_page_range was used incorrectly, in external modules, leading to crashes. This can be partly attributed to the fact that ioremap_page_range is lower-level, with fewer protections, as compared to the other functions that an external module would typically call. Those include: ioremap_cache ioremap_nocache ioremap_prot ioremap_uc ioremap_wc ioremap_wt ...each of which wraps __ioremap_caller, which in turn provides a safer way to achieve the mapping. Therefore, stop EXPORT-ing ioremap_page_range. Link: http://lkml.kernel.org/r/1485173220-29010-1-git-send-email-zhongjiang@huawei.com Signed-off-by: zhong jiang <zhongjiang@huawei.com> Reviewed-by: John Hubbard <jhubbard@nvidia.com> Suggested-by: John Hubbard <jhubbard@nvidia.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/trace/events/spi.h')