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xenstore: fix suspension when using the xenstore device

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Lock the xenstore request mutex when suspending user-space processes, in order
to prevent any process from holding this lock when going into suspension, or
else the xenstore suspend process is going to deadlock.

Submitted by:		Liuyingdong <liuyingdong@huawei.com>
Reviewed by:		royger
MFC after:		2 weeks
Differential revision:	https://reviews.freebsd.org/D9638
This commit is contained in:
Roger Pau Monné 2017-03-07 09:17:48 +00:00
parent 8dee0e9bd6
commit 41716b8d51
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=314841
3 changed files with 30 additions and 0 deletions
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2
sys/dev/xen/control/control.c
View File

@ -199,7 +199,9 @@ xctrl_suspend()
#endif
EVENTHANDLER_INVOKE(power_suspend_early);
xs_lock();
stop_all_proc();
xs_unlock();
EVENTHANDLER_INVOKE(power_suspend);
#ifdef EARLY_AP_STARTUP

17
sys/dev/xen/xenstore/xenstore.c
View File

@ -1699,3 +1699,20 @@ xs_unregister_watch(struct xs_watch *watch)
sx_xunlock(&xs.xenwatch_mutex);
}
}
void
xs_lock(void)
{
sx_xlock(&xs.request_mutex);
return;
}
void
xs_unlock(void)
{
sx_xunlock(&xs.request_mutex);
return;
}

11
sys/xen/xenstore/xenstorevar.h
View File

@ -338,4 +338,15 @@ void xs_unregister_watch(struct xs_watch *watch);
*/
struct sbuf *xs_join(const char *, const char *);
/**
* Lock the xenstore request mutex.
*/
void xs_lock(void);
/**
* Unlock the xenstore request mutex.
*/
void xs_unlock(void);
#endif /* _XEN_XENSTORE_XENSTOREVAR_H */