target/iscsi: Allocate session IDs from an IDA

Since the session is never looked up by ID, we can use the more
space-efficient IDA instead of the IDR.

Signed-off-by: Matthew Wilcox <willy@infradead.org>

3 files changed, 10 insertions, 30 deletions

diff --git a/drivers/target/iscsi/iscsi_target.c b/drivers/target/iscsi/iscsi_target.c
index 8e223799347a..94bad43c41ff 100644
--- a/drivers/target/iscsi/iscsi_target.c
+++ b/drivers/target/iscsi/iscsi_target.c
@@ -57,9 +57,8 @@ static DEFINE_SPINLOCK(tiqn_lock);
 static DEFINE_MUTEX(np_lock);
 
 static struct idr tiqn_idr;
-struct idr sess_idr;
+DEFINE_IDA(sess_ida);
 struct mutex auth_id_lock;
-spinlock_t sess_idr_lock;
 
 struct iscsit_global *iscsit_global;
 
@@ -700,9 +699,7 @@ static int __init iscsi_target_init_module(void)
 
         spin_lock_init(&iscsit_global->ts_bitmap_lock);
         mutex_init(&auth_id_lock);
-        spin_lock_init(&sess_idr_lock);
         idr_init(&tiqn_idr);
-        idr_init(&sess_idr);
 
         ret = target_register_template(&iscsi_ops);
         if (ret)
@@ -4375,10 +4372,7 @@ int iscsit_close_session(struct iscsi_session *sess)
         pr_debug("Decremented number of active iSCSI Sessions on"
                 " iSCSI TPG: %hu to %u\n", tpg->tpgt, tpg->nsessions);
 
-        spin_lock(&sess_idr_lock);
-        idr_remove(&sess_idr, sess->session_index);
-        spin_unlock(&sess_idr_lock);
-
+        ida_free(&sess_ida, sess->session_index);
         kfree(sess->sess_ops);
         sess->sess_ops = NULL;
         spin_unlock_bh(&se_tpg->session_lock);
diff --git a/drivers/target/iscsi/iscsi_target.h b/drivers/target/iscsi/iscsi_target.h
index 42de1843aa40..48bac0acf8c7 100644
--- a/drivers/target/iscsi/iscsi_target.h
+++ b/drivers/target/iscsi/iscsi_target.h
@@ -55,9 +55,7 @@ extern struct kmem_cache *lio_ooo_cache;
 extern struct kmem_cache *lio_qr_cache;
 extern struct kmem_cache *lio_r2t_cache;
 
-extern struct idr sess_idr;
+extern struct ida sess_ida;
 extern struct mutex auth_id_lock;
-extern spinlock_t sess_idr_lock;
-
 
 #endif   /*** ISCSI_TARGET_H ***/
diff --git a/drivers/target/iscsi/iscsi_target_login.c b/drivers/target/iscsi/iscsi_target_login.c
index 68b3eb00a9d0..b75a8b283581 100644
--- a/drivers/target/iscsi/iscsi_target_login.c
+++ b/drivers/target/iscsi/iscsi_target_login.c
@@ -336,21 +336,15 @@ static int iscsi_login_zero_tsih_s1(
         timer_setup(&sess->time2retain_timer,
                     iscsit_handle_time2retain_timeout, 0);
 
-        idr_preload(GFP_KERNEL);
-        spin_lock_bh(&sess_idr_lock);
-        ret = idr_alloc(&sess_idr, NULL, 0, 0, GFP_NOWAIT);
-        if (ret >= 0)
-                sess->session_index = ret;
-        spin_unlock_bh(&sess_idr_lock);
-        idr_preload_end();
-
+        ret = ida_alloc(&sess_ida, GFP_KERNEL);
         if (ret < 0) {
-                pr_err("idr_alloc() for sess_idr failed\n");
+                pr_err("Session ID allocation failed %d\n", ret);
                 iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR,
                                 ISCSI_LOGIN_STATUS_NO_RESOURCES);
                 goto free_sess;
         }
 
+        sess->session_index = ret;
         sess->creation_time = get_jiffies_64();
         /*
          * The FFP CmdSN window values will be allocated from the TPG's
@@ -364,7 +358,7 @@ static int iscsi_login_zero_tsih_s1(
                                 ISCSI_LOGIN_STATUS_NO_RESOURCES);
                 pr_err("Unable to allocate memory for"
                                 " struct iscsi_sess_ops.\n");
-                goto remove_idr;
+                goto free_id;
         }
 
         sess->se_sess = transport_init_session(TARGET_PROT_NORMAL);
@@ -378,10 +372,8 @@ static int iscsi_login_zero_tsih_s1(
 
 free_ops:
         kfree(sess->sess_ops);
-remove_idr:
-        spin_lock_bh(&sess_idr_lock);
-        idr_remove(&sess_idr, sess->session_index);
-        spin_unlock_bh(&sess_idr_lock);
+free_id:
+        ida_free(&sess_ida, sess->session_index);
 free_sess:
         kfree(sess);
         conn->sess = NULL;
@@ -1170,11 +1162,7 @@ void iscsi_target_login_sess_out(struct iscsi_conn *conn,
                 goto old_sess_out;
 
         transport_free_session(conn->sess->se_sess);
-
-        spin_lock_bh(&sess_idr_lock);
-        idr_remove(&sess_idr, conn->sess->session_index);
-        spin_unlock_bh(&sess_idr_lock);
-
+        ida_free(&sess_ida, conn->sess->session_index);
         kfree(conn->sess->sess_ops);
         kfree(conn->sess);
         conn->sess = NULL;