[RFC PATCH V4 05/18] Add d->max_evtchns

[Wei Liu <wei.liu2@citrix.com>]

This variable indicates the maximum number of event channels a domain can use.

Also replace MAX_EVTCHNS macro with inline function as this function will be
used to calculate max event channels in the future.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
 xen/common/event_channel.c |    5 +++--
 xen/common/schedule.c      |    2 +-
 xen/include/xen/event.h    |    7 +++++--
 xen/include/xen/sched.h    |    1 +
 4 files changed, 10 insertions(+), 5 deletions(-)

diff --git a/xen/common/event_channel.c b/xen/common/event_channel.c
index 6cb082e..0205c73 100644
--- a/xen/common/event_channel.c
+++ b/xen/common/event_channel.c
@@ -134,7 +134,7 @@ static int get_free_port(struct domain *d)
         if ( evtchn_from_port(d, port)->state == ECS_FREE )
             return port;
 
-    if ( port == MAX_EVTCHNS(d) )
+    if ( port == d->max_evtchns )
         return -ENOSPC;
 
     chn = xzalloc_array(struct evtchn, EVTCHNS_PER_BUCKET);
@@ -1177,6 +1177,7 @@ int evtchn_init(struct domain *d)
 
     if ( d->evtchn == NULL )
         return -ENOMEM;
+    d->max_evtchns = max_evtchns(d);
 
     spin_lock_init(&d->event_lock);
     if ( get_free_port(d) != 0 )
@@ -1270,7 +1271,7 @@ static void domain_dump_evtchn_info(struct domain *d)
 
     spin_lock(&d->event_lock);
 
-    for ( port = 1; port < MAX_EVTCHNS(d); ++port )
+    for ( port = 1; port < d->max_evtchns; ++port )
     {
         const struct evtchn *chn;
         char *ssid;
diff --git a/xen/common/schedule.c b/xen/common/schedule.c
index de11110..22b8ffe 100644
--- a/xen/common/schedule.c
+++ b/xen/common/schedule.c
@@ -698,7 +698,7 @@ static long do_poll(struct sched_poll *sched_poll)
             goto out;
 
         rc = -EINVAL;
-        if ( port >= MAX_EVTCHNS(d) )
+        if ( port >= d->max_evtchns )
             goto out;
 
         rc = 0;
diff --git a/xen/include/xen/event.h b/xen/include/xen/event.h
index 271d792..c63b8b2 100644
--- a/xen/include/xen/event.h
+++ b/xen/include/xen/event.h
@@ -20,7 +20,10 @@
 #else
 #define BITS_PER_EVTCHN_WORD(d) (has_32bit_shinfo(d) ? 32 : BITS_PER_XEN_ULONG)
 #endif
-#define MAX_EVTCHNS(d) (BITS_PER_EVTCHN_WORD(d) * BITS_PER_EVTCHN_WORD(d))
+static inline unsigned int max_evtchns(struct domain *d)
+{
+    return BITS_PER_EVTCHN_WORD(d) * BITS_PER_EVTCHN_WORD(d);
+}
 
 #define EVTCHNS_PER_BUCKET 128
 #define NR_EVTCHN_BUCKETS  (NR_EVENT_CHANNELS / EVTCHNS_PER_BUCKET)
@@ -119,7 +122,7 @@ void notify_via_xen_event_channel(struct domain *ld, int lport);
 #define bucket_from_port(d,p) \
     ((d)->evtchn[(p)/EVTCHNS_PER_BUCKET])
 #define port_is_valid(d,p)    \
-    (((p) >= 0) && ((p) < MAX_EVTCHNS(d)) && \
+    (((p) >= 0) && ((p) < d->max_evtchns) && \
      (bucket_from_port(d,p) != NULL))
 #define evtchn_from_port(d,p) \
     (&(bucket_from_port(d,p))[(p)&(EVTCHNS_PER_BUCKET-1)])
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index 58b7176..ad0f042 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -217,6 +217,7 @@ struct domain
     /* Event channel information. */
     struct evtchn  **evtchn;
     spinlock_t       event_lock;
+    unsigned int     max_evtchns;
 
     struct grant_table *grant_table;
 
-- 
1.7.10.4