sctp: convert to idr_alloc()

Convert to the much saner new idr interface.
Signed-off-by: NTejun Heo <tj@kernel.org>
Acked-by: NNeil Horman <nhorman@tuxdriver.com>
Acked-by: NVlad Yasevich <vyasevich@gmail.com>
Cc: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

net/sctp/associola.c

@@ -1591,32 +1591,31 @@ int sctp_assoc_lookup_laddr(struct sctp_association *asoc,
 /* Set an association id for a given association */
 int sctp_assoc_set_id(struct sctp_association *asoc, gfp_t gfp)
 {
-	int assoc_id;
-	int error = 0;
+	bool preload = gfp & __GFP_WAIT;
+	int ret;
 
 	/* If the id is already assigned, keep it. */
 	if (asoc->assoc_id)
-		return error;
-retry:
-	if (unlikely(!idr_pre_get(&sctp_assocs_id, gfp)))
-		return -ENOMEM;
+		return 0;
 
+	if (preload)
+		idr_preload(gfp);
 	spin_lock_bh(&sctp_assocs_id_lock);
-	error = idr_get_new_above(&sctp_assocs_id, (void *)asoc,
-				    idr_low, &assoc_id);
-	if (!error) {
-		idr_low = assoc_id + 1;
+	/* 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;
 	}
 	spin_unlock_bh(&sctp_assocs_id_lock);
-	if (error == -EAGAIN)
-		goto retry;
-	else if (error)
-		return error;
+	if (preload)
+		idr_preload_end();
+	if (ret < 0)
+		return ret;
 
-	asoc->assoc_id = (sctp_assoc_t) assoc_id;
-	return error;
+	asoc->assoc_id = (sctp_assoc_t)ret;
+	return 0;
 }
 
 /* Free the ASCONF queue */