iscsi-target: Add iser network portal attribute

This patch adds a new network portal attribute for iser, that lives
under existing iscsi-target configfs layout at:

   /sys/kernel/config/target/iscsi/$TARGETNAME/$TPGT/np/$PORTAL/iser

When lio_target_np_store_iser() is enabled, iscsit_tpg_add_network_portal()
will attempt to start an rdma_cma network portal for iser-target, only if
the external ib_isert module transport has been loaded.

When disabled, iscsit_tpg_del_network_portal() will cease iser login service
on the network portal, and release any external ib_isert module reference.

v4 changes:

- Add request_module for ib_isert to lio_target_np_store_iser()

Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 79 insertions, 0 deletions

diff --git a/drivers/target/iscsi/iscsi_target_configfs.c b/drivers/target/iscsi/iscsi_target_configfs.c
index 2704daf6ba74..13e9e715ad2e 100644
--- a/drivers/target/iscsi/iscsi_target_configfs.c
+++ b/drivers/target/iscsi/iscsi_target_configfs.c
@@ -125,8 +125,87 @@ out:
 
 TF_NP_BASE_ATTR(lio_target, sctp, S_IRUGO | S_IWUSR);
 
+static ssize_t lio_target_np_show_iser(
+        struct se_tpg_np *se_tpg_np,
+        char *page)
+{
+        struct iscsi_tpg_np *tpg_np = container_of(se_tpg_np,
+                                struct iscsi_tpg_np, se_tpg_np);
+        struct iscsi_tpg_np *tpg_np_iser;
+        ssize_t rb;
+
+        tpg_np_iser = iscsit_tpg_locate_child_np(tpg_np, ISCSI_INFINIBAND);
+        if (tpg_np_iser)
+                rb = sprintf(page, "1\n");
+        else
+                rb = sprintf(page, "0\n");
+
+        return rb;
+}
+
+static ssize_t lio_target_np_store_iser(
+        struct se_tpg_np *se_tpg_np,
+        const char *page,
+        size_t count)
+{
+        struct iscsi_np *np;
+        struct iscsi_portal_group *tpg;
+        struct iscsi_tpg_np *tpg_np = container_of(se_tpg_np,
+                                struct iscsi_tpg_np, se_tpg_np);
+        struct iscsi_tpg_np *tpg_np_iser = NULL;
+        char *endptr;
+        u32 op;
+        int rc;
+
+        op = simple_strtoul(page, &endptr, 0);
+        if ((op != 1) && (op != 0)) {
+                pr_err("Illegal value for tpg_enable: %u\n", op);
+                return -EINVAL;
+        }
+        np = tpg_np->tpg_np;
+        if (!np) {
+                pr_err("Unable to locate struct iscsi_np from"
+                                " struct iscsi_tpg_np\n");
+                return -EINVAL;
+        }
+
+        tpg = tpg_np->tpg;
+        if (iscsit_get_tpg(tpg) < 0)
+                return -EINVAL;
+
+        if (op) {
+                int rc = request_module("ib_isert");
+                if (rc != 0)
+                        pr_warn("Unable to request_module for ib_isert\n");
+
+                tpg_np_iser = iscsit_tpg_add_network_portal(tpg, &np->np_sockaddr,
+                                np->np_ip, tpg_np, ISCSI_INFINIBAND);
+                if (!tpg_np_iser || IS_ERR(tpg_np_iser))
+                        goto out;
+        } else {
+                tpg_np_iser = iscsit_tpg_locate_child_np(tpg_np, ISCSI_INFINIBAND);
+                if (!tpg_np_iser)
+                        goto out;
+
+                rc = iscsit_tpg_del_network_portal(tpg, tpg_np_iser);
+                if (rc < 0)
+                        goto out;
+        }
+
+        printk("lio_target_np_store_iser() done, op: %d\n", op);
+
+        iscsit_put_tpg(tpg);
+        return count;
+out:
+        iscsit_put_tpg(tpg);
+        return -EINVAL;
+}
+
+TF_NP_BASE_ATTR(lio_target, iser, S_IRUGO | S_IWUSR);
+
 static struct configfs_attribute *lio_target_portal_attrs[] = {
         &lio_target_np_sctp.attr,
+        &lio_target_np_iser.attr,
         NULL,
 };