From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Vrabel Subject: [PATCHv2 2/5] evtchn: simplify port_is_valid() Date: Mon, 15 Jun 2015 16:48:16 +0100 Message-ID: <1434383299-21833-3-git-send-email-david.vrabel@citrix.com> References: <1434383299-21833-1-git-send-email-david.vrabel@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta5.messagelabs.com ([195.245.231.135]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1Z4XOx-00006P-QG for xen-devel@lists.xenproject.org; Mon, 15 Jun 2015 16:38:23 +0000 In-Reply-To: <1434383299-21833-1-git-send-email-david.vrabel@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: xen-devel@lists.xenproject.org Cc: Keir Fraser , Tim Deegan , David Vrabel , Jan Beulich , Ian Campbell List-Id: xen-devel@lists.xenproject.org By keeping a count of the number of currently valid event channels, port_is_valid() can be simplified. d->valid_evtchns can also be tested without holding d->event_lock which will be useful later on. Signed-off-by: David Vrabel --- v2: - Used unsigned int for d->valid_evtchns. --- xen/common/event_channel.c | 3 +++ xen/include/xen/event.h | 4 +--- xen/include/xen/sched.h | 5 +++-- 3 files changed, 7 insertions(+), 5 deletions(-) diff --git a/xen/common/event_channel.c b/xen/common/event_channel.c index 947880f..fd48646 100644 --- a/xen/common/event_channel.c +++ b/xen/common/event_channel.c @@ -189,6 +189,8 @@ static int get_free_port(struct domain *d) return -ENOMEM; bucket_from_port(d, port) = chn; + write_atomic(&d->valid_evtchns, d->valid_evtchns + EVTCHNS_PER_BUCKET); + return port; } @@ -1254,6 +1256,7 @@ int evtchn_init(struct domain *d) d->evtchn = alloc_evtchn_bucket(d, 0); if ( !d->evtchn ) return -ENOMEM; + d->valid_evtchns = EVTCHNS_PER_BUCKET; spin_lock_init_prof(d, event_lock); if ( get_free_port(d) != 0 ) diff --git a/xen/include/xen/event.h b/xen/include/xen/event.h index 690f865..a08ecdb 100644 --- a/xen/include/xen/event.h +++ b/xen/include/xen/event.h @@ -91,9 +91,7 @@ static inline bool_t port_is_valid(struct domain *d, unsigned int p) return 0; if ( !d->evtchn ) return 0; - if ( p < EVTCHNS_PER_BUCKET ) - return 1; - return group_from_port(d, p) != NULL && bucket_from_port(d, p) != NULL; + return p < read_atomic(&d->valid_evtchns); } static inline struct evtchn *evtchn_from_port(struct domain *d, unsigned int p) diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h index 80c6f62..604d047 100644 --- a/xen/include/xen/sched.h +++ b/xen/include/xen/sched.h @@ -336,8 +336,9 @@ struct domain /* Event channel information. */ struct evtchn *evtchn; /* first bucket only */ struct evtchn **evtchn_group[NR_EVTCHN_GROUPS]; /* all other buckets */ - unsigned int max_evtchns; - unsigned int max_evtchn_port; + unsigned int max_evtchns; /* number supported by ABI */ + unsigned int max_evtchn_port; /* max permitted port number */ + unsigned int valid_evtchns; /* number of allocated event channels */ spinlock_t event_lock; const struct evtchn_port_ops *evtchn_port_ops; struct evtchn_fifo_domain *evtchn_fifo; -- 1.7.10.4