| Message ID | 20200310072853.27567-5-jgross@suse.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | xen/rcu: let rcu work better with core scheduling | expand |
On 10.03.2020 08:28, Juergen Gross wrote: > rcu_lock_domain() misuses the domain structure as rcu lock, which is > working only as long as rcu_read_lock() isn't evaluating the lock. > > Fix that by adding a rcu lock to struct domain and use that for > rcu_lock_domain(). > > Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Jan Beulich <jbeulich@suse.com> I guess this one is independent of patches 2 and 3, and hence could go in together with patch 1? Jan
On 11.03.20 12:35, Jan Beulich wrote: > On 10.03.2020 08:28, Juergen Gross wrote: >> rcu_lock_domain() misuses the domain structure as rcu lock, which is >> working only as long as rcu_read_lock() isn't evaluating the lock. >> >> Fix that by adding a rcu lock to struct domain and use that for >> rcu_lock_domain(). >> >> Signed-off-by: Juergen Gross <jgross@suse.com> > > Reviewed-by: Jan Beulich <jbeulich@suse.com> > > I guess this one is independent of patches 2 and 3, and hence could > go in together with patch 1? Yes. Juergen
diff --git a/xen/common/domain.c b/xen/common/domain.c index 6ad458fa6b..b4eb476a9c 100644 --- a/xen/common/domain.c +++ b/xen/common/domain.c @@ -398,6 +398,7 @@ struct domain *domain_create(domid_t domid, goto fail; atomic_set(&d->refcnt, 1); + RCU_READ_LOCK_INIT(&d->rcu_lock); spin_lock_init_prof(d, domain_lock); spin_lock_init_prof(d, page_alloc_lock); spin_lock_init(&d->hypercall_deadlock_mutex); diff --git a/xen/include/xen/rcupdate.h b/xen/include/xen/rcupdate.h index 87f35b7704..31c8b86d13 100644 --- a/xen/include/xen/rcupdate.h +++ b/xen/include/xen/rcupdate.h @@ -65,6 +65,7 @@ int rcu_needs_cpu(int cpu); struct _rcu_read_lock {}; typedef struct _rcu_read_lock rcu_read_lock_t; #define DEFINE_RCU_READ_LOCK(x) rcu_read_lock_t x +#define RCU_READ_LOCK_INIT(x) /** * rcu_read_lock - mark the beginning of an RCU read-side critical section. diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h index 3a4f43098c..647e4d31fb 100644 --- a/xen/include/xen/sched.h +++ b/xen/include/xen/sched.h @@ -348,6 +348,8 @@ struct domain shared_info_t *shared_info; /* shared data area */ + rcu_read_lock_t rcu_lock; + spinlock_t domain_lock; spinlock_t page_alloc_lock; /* protects all the following fields */ @@ -634,13 +636,13 @@ int rcu_lock_live_remote_domain_by_id(domid_t dom, struct domain **d); static inline void rcu_unlock_domain(struct domain *d) { if ( d != current->domain ) - rcu_read_unlock(d); + rcu_read_unlock(&d->rcu_lock); } static inline struct domain *rcu_lock_domain(struct domain *d) { if ( d != current->domain ) - rcu_read_lock(d); + rcu_read_lock(&d->rcu_lock); return d; }
rcu_lock_domain() misuses the domain structure as rcu lock, which is working only as long as rcu_read_lock() isn't evaluating the lock. Fix that by adding a rcu lock to struct domain and use that for rcu_lock_domain(). Signed-off-by: Juergen Gross <jgross@suse.com> --- xen/common/domain.c | 1 + xen/include/xen/rcupdate.h | 1 + xen/include/xen/sched.h | 6 ++++-- 3 files changed, 6 insertions(+), 2 deletions(-)