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/*
* Common code for control of lockd and nfsv4 grace periods.
*/
#include <linux/module.h>
#include <linux/lockd/bind.h>
#include <net/net_namespace.h>
#include "netns.h"
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)
{
struct net *net = &init_net;
struct lockd_net *ln = net_generic(net, lockd_net_id);
spin_lock(&grace_lock);
list_add(&lm->list, &ln->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)
{
struct net *net = &init_net;
struct lockd_net *ln = net_generic(net, lockd_net_id);
return !list_empty(&ln->grace_list);
}
EXPORT_SYMBOL_GPL(locks_in_grace);
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