blob: 183cc1f0af1cf6be225053e2032f47a063be25d3 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
|
/*
* 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);
|
