[PATCH v3 04/18] nvmet-fcloop: refactor fcloop_nport_alloc

[Daniel Wagner <wagi@kernel.org>]

There are many different operations done under the spin lock. Since the
lport and nport are ref counted it's possible to use the spin lock only
for the list insert and lookup.

This allows us to untangle the setup steps into a more linear form which
reduces the complexity of the functions.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Daniel Wagner <wagi@kernel.org>
---
 drivers/nvme/target/fcloop.c | 156 +++++++++++++++++++++++--------------------
 1 file changed, 84 insertions(+), 72 deletions(-)

diff --git a/drivers/nvme/target/fcloop.c b/drivers/nvme/target/fcloop.c
index c6d5a31ce0b5ccb10988e339ae22d528e06d5e2b..245bfe08d91ec81f1979251e8c757a0d46fd09e9 100644
--- a/drivers/nvme/target/fcloop.c
+++ b/drivers/nvme/target/fcloop.c
@@ -1027,6 +1027,8 @@ fcloop_nport_put(struct fcloop_nport *nport)
 	list_del(&nport->nport_list);
 	spin_unlock_irqrestore(&fcloop_lock, flags);
 
+	if (nport->lport)
+		fcloop_lport_put(nport->lport);
 	kfree(nport);
 }
 
@@ -1189,33 +1191,63 @@ __wait_localport_unreg(struct fcloop_lport *lport)
 	return ret;
 }
 
+static struct fcloop_lport *
+fcloop_lport_lookup(u64 node_name, u64 port_name)
+{
+	struct fcloop_lport *lp, *lport = NULL;
+	unsigned long flags;
+
+	spin_lock_irqsave(&fcloop_lock, flags);
+	list_for_each_entry(lp, &fcloop_lports, lport_list) {
+		if (lp->localport->node_name != node_name ||
+		    lp->localport->port_name != port_name)
+			continue;
+
+		if (fcloop_lport_get(lp))
+			lport = lp;
+
+		break;
+	}
+	spin_unlock_irqrestore(&fcloop_lock, flags);
+
+	return lport;
+}
+
+static struct fcloop_nport *
+fcloop_nport_lookup(u64 node_name, u64 port_name)
+{
+	struct fcloop_nport *np, *nport = NULL;
+	unsigned long flags;
+
+	spin_lock_irqsave(&fcloop_lock, flags);
+	list_for_each_entry(np, &fcloop_nports, nport_list) {
+		if (np->node_name != node_name ||
+		    np->port_name != port_name)
+			continue;
+
+		if (fcloop_nport_get(np))
+			nport = np;
+
+		break;
+	}
+	spin_unlock_irqrestore(&fcloop_lock, flags);
+
+	return nport;
+}
 
 static ssize_t
 fcloop_delete_local_port(struct device *dev, struct device_attribute *attr,
 		const char *buf, size_t count)
 {
-	struct fcloop_lport *tlport, *lport = NULL;
+	struct fcloop_lport *lport;
 	u64 nodename, portname;
-	unsigned long flags;
 	int ret;
 
 	ret = fcloop_parse_nm_options(dev, &nodename, &portname, buf);
 	if (ret)
 		return ret;
 
-	spin_lock_irqsave(&fcloop_lock, flags);
-
-	list_for_each_entry(tlport, &fcloop_lports, lport_list) {
-		if (tlport->localport->node_name == nodename &&
-		    tlport->localport->port_name == portname) {
-			if (!fcloop_lport_get(tlport))
-				break;
-			lport = tlport;
-			break;
-		}
-	}
-	spin_unlock_irqrestore(&fcloop_lock, flags);
-
+	lport = fcloop_lport_lookup(nodename, portname);
 	if (!lport)
 		return -ENOENT;
 
@@ -1228,9 +1260,9 @@ fcloop_delete_local_port(struct device *dev, struct device_attribute *attr,
 static struct fcloop_nport *
 fcloop_alloc_nport(const char *buf, size_t count, bool remoteport)
 {
-	struct fcloop_nport *newnport, *nport = NULL;
-	struct fcloop_lport *tmplport, *lport = NULL;
 	struct fcloop_ctrl_options *opts;
+	struct fcloop_nport *nport;
+	struct fcloop_lport *lport;
 	unsigned long flags;
 	u32 opts_mask = (remoteport) ? RPORT_OPTS : TGTPORT_OPTS;
 	int ret;
@@ -1244,79 +1276,59 @@ fcloop_alloc_nport(const char *buf, size_t count, bool remoteport)
 		goto out_free_opts;
 
 	/* everything there ? */
-	if ((opts->mask & opts_mask) != opts_mask) {
-		ret = -EINVAL;
+	if ((opts->mask & opts_mask) != opts_mask)
 		goto out_free_opts;
-	}
 
-	newnport = kzalloc(sizeof(*newnport), GFP_KERNEL);
-	if (!newnport)
+	lport = fcloop_lport_lookup(opts->wwnn, opts->wwpn);
+	if (lport) {
+		/* invalid configuration */
+		fcloop_lport_put(lport);
 		goto out_free_opts;
+	}
 
-	INIT_LIST_HEAD(&newnport->nport_list);
-	newnport->node_name = opts->wwnn;
-	newnport->port_name = opts->wwpn;
-	if (opts->mask & NVMF_OPT_ROLES)
-		newnport->port_role = opts->roles;
-	if (opts->mask & NVMF_OPT_FCADDR)
-		newnport->port_id = opts->fcaddr;
-	refcount_set(&newnport->ref, 1);
+	nport = fcloop_nport_lookup(opts->wwnn, opts->wwpn);
+	if (nport && ((remoteport && nport->rport) ||
+		      (!remoteport && nport->tport))) {
+		/* invalid configuration */
+		goto out_put_nport;
+	}
 
-	spin_lock_irqsave(&fcloop_lock, flags);
+	if (!nport) {
+		nport = kzalloc(sizeof(*nport), GFP_KERNEL);
+		if (!nport)
+			goto out_free_opts;
 
-	list_for_each_entry(tmplport, &fcloop_lports, lport_list) {
-		if (tmplport->localport->node_name == opts->wwnn &&
-		    tmplport->localport->port_name == opts->wwpn)
-			goto out_invalid_opts;
+		INIT_LIST_HEAD(&nport->nport_list);
+		nport->node_name = opts->wwnn;
+		nport->port_name = opts->wwpn;
+		refcount_set(&nport->ref, 1);
 
-		if (tmplport->localport->node_name == opts->lpwwnn &&
-		    tmplport->localport->port_name == opts->lpwwpn)
-			lport = tmplport;
+		spin_lock_irqsave(&fcloop_lock, flags);
+		list_add_tail(&nport->nport_list, &fcloop_nports);
+		spin_unlock_irqrestore(&fcloop_lock, flags);
 	}
 
+	if (opts->mask & NVMF_OPT_ROLES)
+		nport->port_role = opts->roles;
+	if (opts->mask & NVMF_OPT_FCADDR)
+		nport->port_id = opts->fcaddr;
+
 	if (remoteport) {
+		lport = fcloop_lport_lookup(opts->lpwwnn, opts->lpwwpn);
 		if (!lport)
-			goto out_invalid_opts;
-		newnport->lport = lport;
-	}
-
-	list_for_each_entry(nport, &fcloop_nports, nport_list) {
-		if (nport->node_name == opts->wwnn &&
-		    nport->port_name == opts->wwpn) {
-			if ((remoteport && nport->rport) ||
-			    (!remoteport && nport->tport)) {
-				nport = NULL;
-				goto out_invalid_opts;
-			}
-
-			fcloop_nport_get(nport);
+			goto out_put_nport;
 
-			spin_unlock_irqrestore(&fcloop_lock, flags);
-
-			if (remoteport)
-				nport->lport = lport;
-			if (opts->mask & NVMF_OPT_ROLES)
-				nport->port_role = opts->roles;
-			if (opts->mask & NVMF_OPT_FCADDR)
-				nport->port_id = opts->fcaddr;
-			goto out_free_newnport;
-		}
+		nport->lport = lport;
 	}
 
-	list_add_tail(&newnport->nport_list, &fcloop_nports);
-
-	spin_unlock_irqrestore(&fcloop_lock, flags);
-
 	kfree(opts);
-	return newnport;
+	return nport;
 
-out_invalid_opts:
-	spin_unlock_irqrestore(&fcloop_lock, flags);
-out_free_newnport:
-	kfree(newnport);
+out_put_nport:
+	fcloop_nport_put(nport);
 out_free_opts:
 	kfree(opts);
-	return nport;
+	return NULL;
 }
 
 static ssize_t

-- 
2.48.1