libports: use a global hash table for the lookups

Previously, libports used a hash table per port bucket.  This makes
looking up a port difficult if one does not know the port bucket, as
one has to iterate over all buckets and do a hash table lookup each.

Having to iterate over the buckets makes it necessary to keep a list
of all buckets, which has to be updated and protected by a lock as
well.

Also, the current code in _ports_bucket_class_iterate iterates over
the hash table associated with the bucket given.  When
ports_class_iterate calls this common function, it obtains a reference
to the bucket from one of the ports in the given class.  This will not
work if a class contains ports in different port buckets.  This
limitation is not documented as far as I can see.  Again, having to
maintain this list has its cost and requires serialization.

Use a global hash table for lookups instead.  Keep the per-bucket hash
tables for efficient iteration over buckets.  Furthermore, serialize
access to all hash tables using a separate lock.  Remove the linked
lists of all buckets and all ports in a class.

* libports/bucket-iterate.c (ports_bucket_iterate): Acquire
_ports_htable_lock.  Also, generalize ports_bucket_iterate so that it
takes a pointer to a hash table as first argument.
(ports_bucket_iterate): Ajust call to former function accordingly.
* libports/class-iterate.c (ports_class_iterate): Just call the
generalized _ports_bucket_class_iterate with the global hash table as
argument.
* libports/ports.h (struct port_info): Remove the port class links.
(struct port_bucket): Remove the hash table, and the all buckets link.
(_ports_all_buckets): Remove declaration.
(_ports_htable): New global hash table.
(_ports_htable_lock): Protected by this lock.
* libports/claim-right.c: Adjust accordingly.
* libports/complete-deallocate.c: Likewise.
* libports/create-bucket.c: Likewise.
* libports/create-class.c: Likewise.
* libports/create-internal.c: Likewise.
* libports/destroy-right.c: Likewise.
* libports/import-port.c: Likewise.
* libports/lookup-port.c: Likewise.
* libports/reallocate-from-external.c: Likewise.
* libports/reallocate-port.c: Likewise.
* libports/transfer-right.c: Likewise.
* libports/inhibit-all-rpcs.c: Iterate over the hash table.
* libports/inhibit-bucket-rpcs.c: Likewise, but filter using bucket.
* libports/inhibit-class-rpcs.c: Likewise, but filter using class.
* libports/init.c (_ports_htable): Initialize.
(_ports_htable_lock): Likewise.

1 files changed, 13 insertions, 14 deletions

diff --git a/libports/inhibit-all-rpcs.c b/libports/inhibit-all-rpcs.c
index d4a54ba5..27e2ec54 100644
--- a/libports/inhibit-all-rpcs.c
+++ b/libports/inhibit-all-rpcs.c
@@ -36,24 +36,23 @@ ports_inhibit_all_rpcs ()
       struct port_bucket *bucket;
       int this_one = 0;
 
-      for (bucket = _ports_all_buckets; bucket; bucket = bucket->next)
+      pthread_rwlock_rdlock (&_ports_htable_lock);
+      HURD_IHASH_ITERATE (&_ports_htable, portstruct)
 	{
-	  HURD_IHASH_ITERATE (&bucket->htable, portstruct)
+	  struct rpc_info *rpc;
+	  struct port_info *pi = portstruct;
+
+	  for (rpc = pi->current_rpcs; rpc; rpc = rpc->next)
 	    {
-	      struct rpc_info *rpc;
-	      struct port_info *pi = portstruct;
-	  
-	      for (rpc = pi->current_rpcs; rpc; rpc = rpc->next)
-		{
-		  /* Avoid cancelling the calling thread if it's currently
-		     handling a RPC.  */
-		  if (rpc->thread == hurd_thread_self ())
-		    this_one = 1;
-		  else
-		    hurd_thread_cancel (rpc->thread);
-		}
+	      /* Avoid cancelling the calling thread if it's currently
+		 handling a RPC.  */
+	      if (rpc->thread == hurd_thread_self ())
+		this_one = 1;
+	      else
+		hurd_thread_cancel (rpc->thread);
 	    }
 	}
+      pthread_rwlock_unlock (&_ports_htable_lock);
 
       while (_ports_total_rpcs > this_one)
 	{