iscsi-target: Convert to per-cpu ida_alloc + ida_free command map

This patch changes iscsi-target to use transport_alloc_session_tags()
pre-allocation logic for per-cpu session tag pooling with internal
ida_alloc() + ida_free() calls based upon the saved se_cmd->map_tag id.

This includes tag pool setup based upon per NodeACL queue_depth after
locating se_node_acl in iscsi_target_locate_portal().

Also update iscsit_allocate_cmd() and iscsit_release_cmd() to use
percpu_ida_alloc() and percpu_ida_free() respectively.

v5 changes;
  - Convert to percpu_ida.h include

v2 changes:
  - Fix bug with SessionType=Discovery in iscsi_target_locate_portal()

Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Kent Overstreet <kmo@daterainc.com>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>

diff --git a/drivers/target/iscsi/iscsi_target_core.h b/drivers/target/iscsi/iscsi_target_core.h
index 129b7d77c7cb9662973cb7ca481e59338af1468e..af3cd7a4779969f0ea74bffd72f5e89a0de547a0 100644 (file)
--- a/drivers/target/iscsi/iscsi_target_core.h
+++ b/drivers/target/iscsi/iscsi_target_core.h
@@ -17,6 +17,8 @@
 #define SECONDS_FOR_ASYNC_TEXT         10
 #define SECONDS_FOR_LOGOUT_COMP                15
 #define WHITE_SPACE                    " \t\v\f\n\r"
+#define ISCSIT_MIN_TAGS                        16
+#define ISCSIT_EXTRA_TAGS              8
 
 /* struct iscsi_node_attrib sanity values */
 #define NA_DATAOUT_TIMEOUT             3

diff --git a/drivers/target/iscsi/iscsi_target_nego.c b/drivers/target/iscsi/iscsi_target_nego.c
index 2cce636d111350033a1647da87d57fb2c7eaaca1..24b0e33e7c50199d758652ca7aafdddfe619bb48 100644 (file)
--- a/drivers/target/iscsi/iscsi_target_nego.c
+++ b/drivers/target/iscsi/iscsi_target_nego.c
@@ -983,8 +983,9 @@ int iscsi_target_locate_portal(
        struct iscsi_tiqn *tiqn;
        struct iscsi_tpg_np *tpg_np = NULL;
        struct iscsi_login_req *login_req;
-       u32 payload_length;
-       int sessiontype = 0, ret = 0;
+       struct se_node_acl *se_nacl;
+       u32 payload_length, queue_depth = 0;
+       int sessiontype = 0, ret = 0, tag_num, tag_size;
 
        INIT_DELAYED_WORK(&conn->login_work, iscsi_target_do_login_rx);
        INIT_DELAYED_WORK(&conn->login_cleanup_work, iscsi_target_do_cleanup);
@@ -1084,7 +1085,7 @@ int iscsi_target_locate_portal(
                        goto out;
                }
                ret = 0;
-               goto out;
+               goto alloc_tags;
        }
 
 get_target:
@@ -1181,8 +1182,27 @@ get_target:
                ret = -1;
                goto out;
        }
+       se_nacl = sess->se_sess->se_node_acl;
+       queue_depth = se_nacl->queue_depth;
+       /*
+        * Setup pre-allocated tags based upon allowed per NodeACL CmdSN
+        * depth for non immediate commands, plus extra tags for immediate
+        * commands.
+        *
+        * Also enforce a ISCSIT_MIN_TAGS to prevent unnecessary contention
+        * in per-cpu-ida tag allocation logic + small queue_depth.
+        */
+alloc_tags:
+       tag_num = max_t(u32, ISCSIT_MIN_TAGS, queue_depth);
+       tag_num += ISCSIT_EXTRA_TAGS;
+       tag_size = sizeof(struct iscsi_cmd) + conn->conn_transport->priv_size;
 
-       ret = 0;
+       ret = transport_alloc_session_tags(sess->se_sess, tag_num, tag_size);
+       if (ret < 0) {
+               iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR,
+                                   ISCSI_LOGIN_STATUS_NO_RESOURCES);
+               ret = -1;
+       }
 out:
        kfree(tmpbuf);
        return ret;

diff --git a/drivers/target/iscsi/iscsi_target_util.c b/drivers/target/iscsi/iscsi_target_util.c
index 5784cad16be12761a27d118bf7ec9eba8108bb95..8d85d8cceb4295f6e07c1d66855b7147c0e880a6 100644 (file)
--- a/drivers/target/iscsi/iscsi_target_util.c
+++ b/drivers/target/iscsi/iscsi_target_util.c
@@ -19,6 +19,7 @@
  ******************************************************************************/
 
 #include <linux/list.h>
+#include <linux/percpu_ida.h>
 #include <scsi/scsi_tcq.h>
 #include <scsi/iscsi_proto.h>
 #include <target/target_core_base.h>
@@ -156,13 +157,15 @@ void iscsit_free_r2ts_from_list(struct iscsi_cmd *cmd)
 struct iscsi_cmd *iscsit_allocate_cmd(struct iscsi_conn *conn, gfp_t gfp_mask)
 {
        struct iscsi_cmd *cmd;
-       int priv_size = conn->conn_transport->priv_size;
+       struct se_session *se_sess = conn->sess->se_sess;
+       int size, tag;
 
-       cmd = kzalloc(sizeof(struct iscsi_cmd) + priv_size, gfp_mask);
-       if (!cmd) {
-               pr_err("Unable to allocate memory for struct iscsi_cmd.\n");
-               return NULL;
-       }
+       tag = percpu_ida_alloc(&se_sess->sess_tag_pool, gfp_mask);
+       size = sizeof(struct iscsi_cmd) + conn->conn_transport->priv_size;
+       cmd = (struct iscsi_cmd *)(se_sess->sess_cmd_map + (tag * size));
+       memset(cmd, 0, size);
+
+       cmd->se_cmd.map_tag = tag;
        cmd->conn = conn;
        INIT_LIST_HEAD(&cmd->i_conn_node);
        INIT_LIST_HEAD(&cmd->datain_list);
@@ -678,6 +681,16 @@ void iscsit_free_queue_reqs_for_conn(struct iscsi_conn *conn)
 
 void iscsit_release_cmd(struct iscsi_cmd *cmd)
 {
+       struct iscsi_session *sess;
+       struct se_cmd *se_cmd = &cmd->se_cmd;
+
+       if (cmd->conn)
+               sess = cmd->conn->sess;
+       else
+               sess = cmd->sess;
+
+       BUG_ON(!sess || !sess->se_sess);
+
        kfree(cmd->buf_ptr);
        kfree(cmd->pdu_list);
        kfree(cmd->seq_list);
@@ -685,7 +698,7 @@ void iscsit_release_cmd(struct iscsi_cmd *cmd)
        kfree(cmd->iov_data);
        kfree(cmd->text_in_ptr);
 
-       kfree(cmd);
+       percpu_ida_free(&sess->se_sess->sess_tag_pool, se_cmd->map_tag);
 }
 EXPORT_SYMBOL(iscsit_release_cmd);