Re: [PATCH-v2 4/4] target: Obtain se_node_acl->acl_kref during get_initiator_node_acl

From: Christoph Hellwig
Date: Wed Jan 13 2016 - 03:15:26 EST


On Wed, Jan 13, 2016 at 12:00:28AM -0800, Nicholas A. Bellinger wrote:
> diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c
> index 52ae8ba..62f02ea 100644
> --- a/drivers/target/target_core_tpg.c
> +++ b/drivers/target/target_core_tpg.c
> @@ -75,16 +75,9 @@ struct se_node_acl *core_tpg_get_initiator_node_acl(
> unsigned char *initiatorname)
> {
> struct se_node_acl *acl;
> - /*
> - * Obtain the acl_kref now, which will be dropped upon the
> - * release of se_sess memory within transport_free_session().
> - */
> +
> mutex_lock(&tpg->acl_node_mutex);
> acl = __core_tpg_get_initiator_node_acl(tpg, initiatorname);
> - if (acl) {
> - if (!kref_get_unless_zero(&acl->acl_kref))
> - acl = NULL;
> - }

nah, please keep the kref_get_unless_zero here, it's needed. It's
just the misleding comment I was complaining about :)

> @@ -3435,10 +3436,14 @@ iscsit_build_sendtargets_response(struct iscsi_cmd *cmd,
>
> if ((tpg->tpg_attrib.generate_node_acls == 0) &&
> (tpg->tpg_attrib.demo_mode_discovery == 0) &&
> - (!core_tpg_get_initiator_node_acl(&tpg->tpg_se_tpg,
> - cmd->conn->sess->sess_ops->InitiatorName))) {
> + (!(se_acl = core_tpg_get_initiator_node_acl(&tpg->tpg_se_tpg,
> + cmd->conn->sess->sess_ops->InitiatorName)))) {
> continue;
> }
> + if (se_acl) {
> + target_put_nacl(se_acl);
> + se_acl = NULL;
> + }


Seems like with the current code we don't need to keep the ACL,
so a new helper like:

bool target_tpg_has_node_acl(struct se_portal_group *tpg,
const char *initiatorname)
{
struct se_node_acl *acl;

acl = core_tpg_get_initiator_node_acl(tpg, initiatorname);
if (acl) {
target_put_nacl(se_acl);
return true;
}

return false;
}

or fully open coded as:

bool target_tpg_has_node_acl(struct se_portal_group *tpg,
const char *initiatorname)
{
struct se_node_acl *acl;
bool found = false;

mutex_lock(&tpg->acl_node_mutex);
list_for_each_entry(acl, &tpg->acl_node_list, acl_list) {
if (!strcmp(acl->initiatorname, initiatorname)) {
found = true;
break;
}
}
mutex_unlock(&tpg->acl_node_mutex);

return found;
}

might be better to keep the code readable.