1 files changed, 40 insertions, 8 deletions

diff --git a/drivers/scsi/libfc/fc_exch.c b/drivers/scsi/libfc/fc_exch.c
index ec2a1aec2350..d21367d3305f 100644
--- a/drivers/scsi/libfc/fc_exch.c
+++ b/drivers/scsi/libfc/fc_exch.c
@@ -67,6 +67,11 @@ struct workqueue_struct *fc_exch_workqueue;
 struct fc_exch_pool {
 	u16		 next_index;
 	u16		 total_exches;
+
+	/* two cache of free slot in exch array */
+	u16		 left;
+	u16		 right;
+
 	spinlock_t	 lock;
 	struct list_head ex_list;
 };
@@ -108,7 +113,6 @@ struct fc_exch_mgr {
 		atomic_t non_bls_resp;
 	} stats;
 };
-#define	fc_seq_exch(sp) container_of(sp, struct fc_exch, seq)
 
 /**
  * struct fc_exch_mgr_anchor - primary structure for list of EMs
@@ -397,13 +401,23 @@ static inline void fc_exch_ptr_set(struct fc_exch_pool *pool, u16 index,
 static void fc_exch_delete(struct fc_exch *ep)
 {
 	struct fc_exch_pool *pool;
+	u16 index;
 
 	pool = ep->pool;
 	spin_lock_bh(&pool->lock);
 	WARN_ON(pool->total_exches <= 0);
 	pool->total_exches--;
-	fc_exch_ptr_set(pool, (ep->xid - ep->em->min_xid) >> fc_cpu_order,
-			NULL);
+
+	/* update cache of free slot */
+	index = (ep->xid - ep->em->min_xid) >> fc_cpu_order;
+	if (pool->left == FC_XID_UNKNOWN)
+		pool->left = index;
+	else if (pool->right == FC_XID_UNKNOWN)
+		pool->right = index;
+	else
+		pool->next_index = index;
+
+	fc_exch_ptr_set(pool, index, NULL);
 	list_del(&ep->ex_list);
 	spin_unlock_bh(&pool->lock);
 	fc_exch_release(ep);	/* drop hold for exch in mp */
@@ -636,10 +650,13 @@ static void fc_exch_timeout(struct work_struct *work)
 		if (e_stat & ESB_ST_ABNORMAL)
 			rc = fc_exch_done_locked(ep);
 		spin_unlock_bh(&ep->ex_lock);
-		if (!rc)
-			fc_exch_delete(ep);
 		if (resp)
 			resp(sp, ERR_PTR(-FC_EX_TIMEOUT), arg);
+		if (!rc) {
+			/* delete the exchange if it's already being aborted */
+			fc_exch_delete(ep);
+			return;
+		}
 		fc_seq_exch_abort(sp, 2 * ep->r_a_tov);
 		goto done;
 	}
@@ -679,6 +696,19 @@ static struct fc_exch *fc_exch_em_alloc(struct fc_lport *lport,
 	pool = per_cpu_ptr(mp->pool, cpu);
 	spin_lock_bh(&pool->lock);
 	put_cpu();
+
+	/* peek cache of free slot */
+	if (pool->left != FC_XID_UNKNOWN) {
+		index = pool->left;
+		pool->left = FC_XID_UNKNOWN;
+		goto hit;
+	}
+	if (pool->right != FC_XID_UNKNOWN) {
+		index = pool->right;
+		pool->right = FC_XID_UNKNOWN;
+		goto hit;
+	}
+
 	index = pool->next_index;
 	/* allocate new exch from pool */
 	while (fc_exch_ptr_get(pool, index)) {
@@ -687,7 +717,7 @@ static struct fc_exch *fc_exch_em_alloc(struct fc_lport *lport,
 			goto err;
 	}
 	pool->next_index = index == mp->pool_max_index ? 0 : index + 1;
-
+hit:
 	fc_exch_hold(ep);	/* hold for exch in mp */
 	spin_lock_init(&ep->ex_lock);
 	/*
@@ -1247,7 +1277,7 @@ static struct fc_seq *fc_seq_assign(struct fc_lport *lport, struct fc_frame *fp)
 
 	list_for_each_entry(ema, &lport->ema_list, ema_list)
 		if ((!ema->match || ema->match(fp)) &&
-		    fc_seq_lookup_recip(lport, ema->mp, fp) != FC_RJT_NONE)
+		    fc_seq_lookup_recip(lport, ema->mp, fp) == FC_RJT_NONE)
 			break;
 	return fr_seq(fp);
 }
@@ -1343,7 +1373,7 @@ static void fc_exch_recv_seq_resp(struct fc_exch_mgr *mp, struct fc_frame *fp)
 	}
 	if (ep->esb_stat & ESB_ST_COMPLETE) {
 		atomic_inc(&mp->stats.xid_not_found);
-		goto out;
+		goto rel;
 	}
 	if (ep->rxid == FC_XID_UNKNOWN)
 		ep->rxid = ntohs(fh->fh_rx_id);
@@ -2181,6 +2211,8 @@ struct fc_exch_mgr *fc_exch_mgr_alloc(struct fc_lport *lport,
 		goto free_mempool;
 	for_each_possible_cpu(cpu) {
 		pool = per_cpu_ptr(mp->pool, cpu);
+		pool->left = FC_XID_UNKNOWN;
+		pool->right = FC_XID_UNKNOWN;
 		spin_lock_init(&pool->lock);
 		INIT_LIST_HEAD(&pool->ex_list);
 	}