|
Hi:
It is well know that is not recomended to keep a spinlock locked during operations that can be preempted. Some of these operations are copy_to_user, copy_from_user. Below is the code of the write_lock() as a sample. 340 static inline void __write_lock(rwlock_t *lock) 341{ 342 preempt_disable(); <<<<<< THE ISSUE IS HERE <<<<<<<<<<<<<< 343 rwlock_acquire(&lock->dep_map, 0, 0, _RET_IP_); 344 LOCK_CONTENDED(lock, _raw_write_trylock, _raw_write_lock); 345} On write_unlock() the preemtion is enable. My question is: Is there any know consequence if I enable preemption before copy_to_user/copy_from user (keeping the spinlock locked) and then disable preemption again after the copy????? i.e.: write_lock(&lock); ....... preempt_enable(); copy_to_user(.......); preempt_disable(); ....... write_unlock(&lock); Thanks in advance. PAP |
_______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
