[PATCH] nvmet-fc: simplify nvmet_fc_alloc_hostport

* [PATCH] nvmet-fc: simplify nvmet_fc_alloc_hostport
@ 2021-03-22 19:57 amit.engel
  2021-03-26 13:32 ` Engel, Amit
                   ` (2 more replies)
  0 siblings, 3 replies; 15+ messages in thread
From: amit.engel @ 2021-03-22 19:57 UTC (permalink / raw)
  To: linux-nvme, james.smart, Chaitanya.Kulkarni; +Cc: amit.engel, James Smart

From: Amit Engel <amit.engel@dell.com>

Once a host is already created,
avoid allocate additional hostports that will be thrown away.
add an helper function to handle host search.

Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Signed-off-by: James Smart <jsmart2021@gmail.com>
Signed-off-by: Amit Engel <amit.engel@dell.com>
---
 drivers/nvme/target/fc.c | 77 ++++++++++++++++++++++++----------------
 1 file changed, 46 insertions(+), 31 deletions(-)

diff --git a/drivers/nvme/target/fc.c b/drivers/nvme/target/fc.c
index d375745fc4ed..cfde3376b8ee 100644
--- a/drivers/nvme/target/fc.c
+++ b/drivers/nvme/target/fc.c
@@ -1020,61 +1020,76 @@ nvmet_fc_free_hostport(struct nvmet_fc_hostport *hostport)
 	nvmet_fc_hostport_put(hostport);
 }
 
+static struct nvmet_fc_hostport *
+nvmet_fc_match_hostport(struct nvmet_fc_tgtport *tgtport, void *hosthandle)
+{
+	struct nvmet_fc_hostport *host;
+
+	lockdep_assert_held(&tgtport->lock);
+
+	list_for_each_entry(host, &tgtport->host_list, host_list) {
+		if (host->hosthandle == hosthandle && !host->invalid) {
+			if (nvmet_fc_hostport_get(host))
+				return (host);
+		}
+	}
+
+	return NULL;
+}
+
 static struct nvmet_fc_hostport *
 nvmet_fc_alloc_hostport(struct nvmet_fc_tgtport *tgtport, void *hosthandle)
 {
-	struct nvmet_fc_hostport *newhost, *host, *match = NULL;
+	struct nvmet_fc_hostport *newhost, *match = NULL;
 	unsigned long flags;
 
 	/* if LLDD not implemented, leave as NULL */
 	if (!hosthandle)
 		return NULL;
 
-	/* take reference for what will be the newly allocated hostport */
+	/*
+	 * take reference for what will be the newly allocated hostport if
+	 * we end up using a new allocation
+	 */
 	if (!nvmet_fc_tgtport_get(tgtport))
 		return ERR_PTR(-EINVAL);
 
+	spin_lock_irqsave(&tgtport->lock, flags);
+	match = nvmet_fc_match_hostport(tgtport, hosthandle);
+	spin_unlock_irqrestore(&tgtport->lock, flags);
+
+	if (match) {
+		/* no new allocation - release reference */
+		nvmet_fc_tgtport_put(tgtport);
+		return match;
+	}
+
 	newhost = kzalloc(sizeof(*newhost), GFP_KERNEL);
 	if (!newhost) {
-		spin_lock_irqsave(&tgtport->lock, flags);
-		list_for_each_entry(host, &tgtport->host_list, host_list) {
-			if (host->hosthandle == hosthandle && !host->invalid) {
-				if (nvmet_fc_hostport_get(host)) {
-					match = host;
-					break;
-				}
-			}
-		}
-		spin_unlock_irqrestore(&tgtport->lock, flags);
-		/* no allocation - release reference */
+		/* no new allocation - release reference */
 		nvmet_fc_tgtport_put(tgtport);
-		return (match) ? match : ERR_PTR(-ENOMEM);
+		return ERR_PTR(-ENOMEM);
 	}
 
-	newhost->tgtport = tgtport;
-	newhost->hosthandle = hosthandle;
-	INIT_LIST_HEAD(&newhost->host_list);
-	kref_init(&newhost->ref);
-
 	spin_lock_irqsave(&tgtport->lock, flags);
-	list_for_each_entry(host, &tgtport->host_list, host_list) {
-		if (host->hosthandle == hosthandle && !host->invalid) {
-			if (nvmet_fc_hostport_get(host)) {
-				match = host;
-				break;
-			}
-		}
-	}
+	match = nvmet_fc_match_hostport(tgtport, hosthandle);
 	if (match) {
+		/* new allocation not needed */
 		kfree(newhost);
-		newhost = NULL;
-		/* releasing allocation - release reference */
+		newhost = match;
+		/* no new allocation - release reference */
 		nvmet_fc_tgtport_put(tgtport);
-	} else
+	} else {
+		newhost->tgtport = tgtport;
+		newhost->hosthandle = hosthandle;
+		INIT_LIST_HEAD(&newhost->host_list);
+		kref_init(&newhost->ref);
+
 		list_add_tail(&newhost->host_list, &tgtport->host_list);
+	}
 	spin_unlock_irqrestore(&tgtport->lock, flags);
 
-	return (match) ? match : newhost;
+	return newhost;
 }
 
 static void
-- 
2.18.2


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