/* * Common code for control of lockd and nfsv4 grace periods. */#include <linux/module.h>#include <linux/lockd/bind.h>static LIST_HEAD(grace_list);static DEFINE_SPINLOCK(grace_lock);/** * locks_start_grace * @lm: who this grace period is for * * A grace period is a period during which locks should not be given * out.  Currently grace periods are only enforced by the two lock * managers (lockd and nfsd), using the locks_in_grace() function to * check when they are in a grace period. * * This function is called to start a grace period. */void locks_start_grace(struct lock_manager *lm){	spin_lock(&grace_lock);	list_add(&lm->list, &grace_list);	spin_unlock(&grace_lock);}EXPORT_SYMBOL_GPL(locks_start_grace);/** * locks_end_grace * @lm: who this grace period is for * * Call this function to state that the given lock manager is ready to * resume regular locking.  The grace period will not end until all lock * managers that called locks_start_grace() also call locks_end_grace(). * Note that callers count on it being safe to call this more than once, * and the second call should be a no-op. */void locks_end_grace(struct lock_manager *lm){	spin_lock(&grace_lock);	list_del_init(&lm->list);	spin_unlock(&grace_lock);}EXPORT_SYMBOL_GPL(locks_end_grace);/** * locks_in_grace * * Lock managers call this function to determine when it is OK for them * to answer ordinary lock requests, and when they should accept only * lock reclaims. */int locks_in_grace(void){	return !list_empty(&grace_list);}EXPORT_SYMBOL_GPL(locks_in_grace);