sctp: convert sctp_assoc_set_id() to use idr_alloc_cyclic()

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Cc: Vlad Yasevich <vyasevich@gmail.com>
Cc: Sridhar Samudrala <sri@us.ibm.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

net/sctp/associola.c

@@ -66,13 +66,6 @@ static void sctp_assoc_bh_rcv(struct work_struct *work);
 static void sctp_assoc_free_asconf_acks(struct sctp_association *asoc);
 static void sctp_assoc_free_asconf_queue(struct sctp_association *asoc);
 
-/* Keep track of the new idr low so that we don't re-use association id
- * numbers too fast.  It is protected by they idr spin lock is in the
- * range of 1 - INT_MAX.
- */
-static u32 idr_low = 1;
-
-
 /* 1st Level Abstractions. */
 
 /* Initialize a new association from provided memory. */
@@ -1601,13 +1594,8 @@ int sctp_assoc_set_id(struct sctp_association *asoc, gfp_t gfp)
 	if (preload)
 		idr_preload(gfp);
 	spin_lock_bh(&sctp_assocs_id_lock);
-	/* 0 is not a valid id, idr_low is always >= 1 */
-	ret = idr_alloc(&sctp_assocs_id, asoc, idr_low, 0, GFP_NOWAIT);
-	if (ret >= 0) {
-		idr_low = ret + 1;
-		if (idr_low == INT_MAX)
-			idr_low = 1;
-	}
+	/* 0 is not a valid assoc_id, must be >= 1 */
+	ret = idr_alloc_cyclic(&sctp_assocs_id, asoc, 1, 0, GFP_NOWAIT);
 	spin_unlock_bh(&sctp_assocs_id_lock);
 	if (preload)
 		idr_preload_end();