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

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

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 ca46830d46ecbaae21f3ee3e69aa7d52905abcae..de1963c34bd88d0335f70de569565740fd395a0a 100644
--- a/drivers/nvme/target/fcloop.c
+++ b/drivers/nvme/target/fcloop.c
@@ -1038,6 +1038,8 @@ fcloop_nport_free(struct kref *ref)
 	list_del(&nport->nport_list);
 	spin_unlock_irqrestore(&fcloop_lock, flags);
 
+	if (nport->lport)
+		fcloop_lport_put(nport->lport);
 	kfree(nport);
 }
 
@@ -1206,33 +1208,63 @@ __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;
 
@@ -1245,9 +1277,9 @@ 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;
@@ -1261,79 +1293,59 @@ 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;
-	kref_init(&newnport->ref);
+	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;
+		kref_init(&nport->ref);
 
-		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

Looks good:

Reviewed-by: Christoph Hellwig <hch@lst.de>

On 2/26/25 19:45, Daniel Wagner wrote:
> There are many different operations done under the spin lock. Since the
> lport and nport are ref counted it's possible to only use for the list
> insert and lookup the spin lock.
> 
... it's possible to use the spin lock only for the list instert and lookup.

> This allows us to untangle the setup steps into a more linear form which
> reduces the complexity of the functions.
> 
> 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 ca46830d46ecbaae21f3ee3e69aa7d52905abcae..de1963c34bd88d0335f70de569565740fd395a0a 100644
> --- a/drivers/nvme/target/fcloop.c
> +++ b/drivers/nvme/target/fcloop.c
> @@ -1038,6 +1038,8 @@ fcloop_nport_free(struct kref *ref)
>   	list_del(&nport->nport_list);
>   	spin_unlock_irqrestore(&fcloop_lock, flags);
>   
> +	if (nport->lport)
> +		fcloop_lport_put(nport->lport);
>   	kfree(nport);
>   }
>   
> @@ -1206,33 +1208,63 @@ __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;
>   
> @@ -1245,9 +1277,9 @@ 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;
> @@ -1261,79 +1293,59 @@ 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;
> -	kref_init(&newnport->ref);
> +	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;
> +		kref_init(&nport->ref);
>   
> -		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);

Don't you need to check here if an 'nport' with the same node_name and
port_name is already present?

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                  Kernel Storage Architect
hare@suse.de                                +49 911 74053 688
SUSE Software Solutions GmbH, Frankenstr. 146, 90461 Nürnberg
HRB 36809 (AG Nürnberg), GF: I. Totev, A. McDonald, W. Knoblich

On Fri, Feb 28, 2025 at 08:11:11AM +0100, Hannes Reinecke wrote:
> > +	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;
> > +		kref_init(&nport->ref);
> > -		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);
> 
> Don't you need to check here if an 'nport' with the same node_name and
> port_name is already present?

There is the existing check which filters out some of the duplicates
(the check is there to allow setting up the target or the remote port
first, so the order doesn't matter), though I am not sure if it would
catch all duplicates. I don't mind adding this, but I'd say it would be
better in a separate patch. I tried to refactor this code without
changing anything else.