Ping? It'd be nice to get some answers to these questions rather than
merging this conversion with the questions still in the changelog ...
----- Forwarded message from Matthew Wilcox <willy@xxxxxxxxxxxxx> -----
Date: Thu, 21 Jun 2018 14:28:27 -0700
From: Matthew Wilcox <willy@xxxxxxxxxxxxx>
To: linux-kernel@xxxxxxxxxxxxxxx
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>, "Nicholas A. Bellinger"
<nab@xxxxxxxxxxxxxxx>, Bart Van Assche <bart.vanassche@xxxxxxx>, Hannes
Reinecke <hare@xxxxxxxx>, Kees Cook <keescook@xxxxxxxxxxxx>, Varun
Prakash <varun@xxxxxxxxxxx>, Sagi Grimberg <sagi@xxxxxxxxxxx>, Philippe
Ombredanne <pombredanne@xxxxxxxx>, Greg Kroah-Hartman
<gregkh@xxxxxxxxxxxxxxxxxxx>, Kate Stewart
<kstewart@xxxxxxxxxxxxxxxxxxx>, Thomas Gleixner <tglx@xxxxxxxxxxxxx>,
"David S. Miller" <davem@xxxxxxxxxxxxx>, Denys Vlasenko
<dvlasenk@xxxxxxxxxx>, linux-scsi@xxxxxxxxxxxxxxx,
target-devel@xxxxxxxxxxxxxxx
Subject: [PATCH 18/26] target/iscsi: Allocate session IDs from an IDA
X-Mailer: git-send-email 2.14.3
Since the session is never looked up by ID, we can use the more
space-efficient IDA instead of the IDR. I think I found a bug where
we never reuse session ID 0, but there may be a good reason for it,
so I've merely documented it in this patch. Not reusing session ID 0
doesn't even leak memory.
Signed-off-by: Matthew Wilcox <willy@xxxxxxxxxxxxx>
---
drivers/target/iscsi/iscsi_target.c | 10 ++--------
drivers/target/iscsi/iscsi_target.h | 4 +---
drivers/target/iscsi/iscsi_target_login.c | 20 ++++++--------------
3 files changed, 9 insertions(+), 25 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 99501785cdc1..561d2ad38989 100644
--- a/drivers/target/iscsi/iscsi_target_login.c
+++ b/drivers/target/iscsi/iscsi_target_login.c
@@ -336,22 +336,16 @@ 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);
kfree(sess);
return -ENOMEM;
}
+ sess->session_index = ret;
sess->creation_time = get_jiffies_64();
/*
* The FFP CmdSN window values will be allocated from the TPG's
@@ -1163,11 +1157,9 @@ void iscsi_target_login_sess_out(struct iscsi_conn *conn,
goto old_sess_out;
if (conn->sess->se_sess)
transport_free_session(conn->sess->se_sess);
- if (conn->sess->session_index != 0) {
- spin_lock_bh(&sess_idr_lock);
- idr_remove(&sess_idr, conn->sess->session_index);
- spin_unlock_bh(&sess_idr_lock);
- }
+ /* Um, 0 is a valid ID. I suppose we never free it? */
+ if (conn->sess->session_index != 0)
+ ida_free(&sess_ida, conn->sess->session_index);
kfree(conn->sess->sess_ops);
kfree(conn->sess);
conn->sess = NULL;
--
2.17.1
----- End forwarded message -----
