This is a note to let you know that I've just added the patch titled
scsi: target: Move sess cmd counter to new struct
to the 6.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
scsi-target-move-sess-cmd-counter-to-new-struct.patch
and it can be found in the queue-6.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 16d7a705f41e3c420430c56b71186dc659d499ae
Author: Mike Christie <michael.christie@xxxxxxxxxx>
Date: Sat Mar 18 20:56:12 2023 -0500
scsi: target: Move sess cmd counter to new struct
[ Upstream commit becd9be6069e7b183c084f460f0eb363e43cc487 ]
iSCSI needs to wait on outstanding commands like how SRP and the FC/FCoE
drivers do. It can't use target_stop_session() because for MCS support we
can't stop the entire session during recovery because if other connections
are OK then we want to be able to continue to execute I/O on them.
Move the per session cmd counters to a new struct so iSCSI can allocate
them per connection. The xcopy code can also just not allocate in the
future since it doesn't need to track commands.
Signed-off-by: Mike Christie <michael.christie@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20230319015620.96006-2-michael.christie@xxxxxxxxxx
Reviewed-by: Maurizio Lombardi <mlombard@xxxxxxxxxx>
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Stable-dep-of: 395cee83d02d ("scsi: target: iscsit: Stop/wait on cmds during conn close")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c
index 736847c933e5c..8ebccdbd94f0e 100644
--- a/drivers/target/target_core_tpg.c
+++ b/drivers/target/target_core_tpg.c
@@ -328,7 +328,7 @@ static void target_shutdown_sessions(struct se_node_acl *acl)
restart:
spin_lock_irqsave(&acl->nacl_sess_lock, flags);
list_for_each_entry(sess, &acl->acl_sess_list, sess_acl_list) {
- if (atomic_read(&sess->stopped))
+ if (sess->cmd_cnt && atomic_read(&sess->cmd_cnt->stopped))
continue;
list_del_init(&sess->sess_acl_list);
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 5926316252eb9..3d6034f00dcd8 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -220,11 +220,49 @@ void transport_subsystem_check_init(void)
sub_api_initialized = 1;
}
-static void target_release_sess_cmd_refcnt(struct percpu_ref *ref)
+static void target_release_cmd_refcnt(struct percpu_ref *ref)
{
- struct se_session *sess = container_of(ref, typeof(*sess), cmd_count);
+ struct target_cmd_counter *cmd_cnt = container_of(ref,
+ typeof(*cmd_cnt),
+ refcnt);
+ wake_up(&cmd_cnt->refcnt_wq);
+}
+
+static struct target_cmd_counter *target_alloc_cmd_counter(void)
+{
+ struct target_cmd_counter *cmd_cnt;
+ int rc;
+
+ cmd_cnt = kzalloc(sizeof(*cmd_cnt), GFP_KERNEL);
+ if (!cmd_cnt)
+ return NULL;
- wake_up(&sess->cmd_count_wq);
+ init_completion(&cmd_cnt->stop_done);
+ init_waitqueue_head(&cmd_cnt->refcnt_wq);
+ atomic_set(&cmd_cnt->stopped, 0);
+
+ rc = percpu_ref_init(&cmd_cnt->refcnt, target_release_cmd_refcnt, 0,
+ GFP_KERNEL);
+ if (rc)
+ goto free_cmd_cnt;
+
+ return cmd_cnt;
+
+free_cmd_cnt:
+ kfree(cmd_cnt);
+ return NULL;
+}
+
+static void target_free_cmd_counter(struct target_cmd_counter *cmd_cnt)
+{
+ /*
+ * Drivers like loop do not call target_stop_session during session
+ * shutdown so we have to drop the ref taken at init time here.
+ */
+ if (!atomic_read(&cmd_cnt->stopped))
+ percpu_ref_put(&cmd_cnt->refcnt);
+
+ percpu_ref_exit(&cmd_cnt->refcnt);
}
/**
@@ -238,25 +276,17 @@ int transport_init_session(struct se_session *se_sess)
INIT_LIST_HEAD(&se_sess->sess_list);
INIT_LIST_HEAD(&se_sess->sess_acl_list);
spin_lock_init(&se_sess->sess_cmd_lock);
- init_waitqueue_head(&se_sess->cmd_count_wq);
- init_completion(&se_sess->stop_done);
- atomic_set(&se_sess->stopped, 0);
- return percpu_ref_init(&se_sess->cmd_count,
- target_release_sess_cmd_refcnt, 0, GFP_KERNEL);
+ se_sess->cmd_cnt = target_alloc_cmd_counter();
+ if (!se_sess->cmd_cnt)
+ return -ENOMEM;
+
+ return 0;
}
EXPORT_SYMBOL(transport_init_session);
void transport_uninit_session(struct se_session *se_sess)
{
- /*
- * Drivers like iscsi and loop do not call target_stop_session
- * during session shutdown so we have to drop the ref taken at init
- * time here.
- */
- if (!atomic_read(&se_sess->stopped))
- percpu_ref_put(&se_sess->cmd_count);
-
- percpu_ref_exit(&se_sess->cmd_count);
+ target_free_cmd_counter(se_sess->cmd_cnt);
}
/**
@@ -2970,9 +3000,16 @@ int target_get_sess_cmd(struct se_cmd *se_cmd, bool ack_kref)
se_cmd->se_cmd_flags |= SCF_ACK_KREF;
}
- if (!percpu_ref_tryget_live(&se_sess->cmd_count))
- ret = -ESHUTDOWN;
-
+ /*
+ * Users like xcopy do not use counters since they never do a stop
+ * and wait.
+ */
+ if (se_sess->cmd_cnt) {
+ if (!percpu_ref_tryget_live(&se_sess->cmd_cnt->refcnt))
+ ret = -ESHUTDOWN;
+ else
+ se_cmd->cmd_cnt = se_sess->cmd_cnt;
+ }
if (ret && ack_kref)
target_put_sess_cmd(se_cmd);
@@ -2993,7 +3030,7 @@ static void target_free_cmd_mem(struct se_cmd *cmd)
static void target_release_cmd_kref(struct kref *kref)
{
struct se_cmd *se_cmd = container_of(kref, struct se_cmd, cmd_kref);
- struct se_session *se_sess = se_cmd->se_sess;
+ struct target_cmd_counter *cmd_cnt = se_cmd->cmd_cnt;
struct completion *free_compl = se_cmd->free_compl;
struct completion *abrt_compl = se_cmd->abrt_compl;
@@ -3004,7 +3041,8 @@ static void target_release_cmd_kref(struct kref *kref)
if (abrt_compl)
complete(abrt_compl);
- percpu_ref_put(&se_sess->cmd_count);
+ if (cmd_cnt)
+ percpu_ref_put(&cmd_cnt->refcnt);
}
/**
@@ -3123,46 +3161,65 @@ void target_show_cmd(const char *pfx, struct se_cmd *cmd)
}
EXPORT_SYMBOL(target_show_cmd);
-static void target_stop_session_confirm(struct percpu_ref *ref)
+static void target_stop_cmd_counter_confirm(struct percpu_ref *ref)
+{
+ struct target_cmd_counter *cmd_cnt = container_of(ref,
+ struct target_cmd_counter,
+ refcnt);
+ complete_all(&cmd_cnt->stop_done);
+}
+
+/**
+ * target_stop_cmd_counter - Stop new IO from being added to the counter.
+ * @cmd_cnt: counter to stop
+ */
+static void target_stop_cmd_counter(struct target_cmd_counter *cmd_cnt)
{
- struct se_session *se_sess = container_of(ref, struct se_session,
- cmd_count);
- complete_all(&se_sess->stop_done);
+ pr_debug("Stopping command counter.\n");
+ if (!atomic_cmpxchg(&cmd_cnt->stopped, 0, 1))
+ percpu_ref_kill_and_confirm(&cmd_cnt->refcnt,
+ target_stop_cmd_counter_confirm);
}
/**
* target_stop_session - Stop new IO from being queued on the session.
- * @se_sess: session to stop
+ * @se_sess: session to stop
*/
void target_stop_session(struct se_session *se_sess)
{
- pr_debug("Stopping session queue.\n");
- if (atomic_cmpxchg(&se_sess->stopped, 0, 1) == 0)
- percpu_ref_kill_and_confirm(&se_sess->cmd_count,
- target_stop_session_confirm);
+ target_stop_cmd_counter(se_sess->cmd_cnt);
}
EXPORT_SYMBOL(target_stop_session);
/**
- * target_wait_for_sess_cmds - Wait for outstanding commands
- * @se_sess: session to wait for active I/O
+ * target_wait_for_cmds - Wait for outstanding cmds.
+ * @cmd_cnt: counter to wait for active I/O for.
*/
-void target_wait_for_sess_cmds(struct se_session *se_sess)
+static void target_wait_for_cmds(struct target_cmd_counter *cmd_cnt)
{
int ret;
- WARN_ON_ONCE(!atomic_read(&se_sess->stopped));
+ WARN_ON_ONCE(!atomic_read(&cmd_cnt->stopped));
do {
pr_debug("Waiting for running cmds to complete.\n");
- ret = wait_event_timeout(se_sess->cmd_count_wq,
- percpu_ref_is_zero(&se_sess->cmd_count),
- 180 * HZ);
+ ret = wait_event_timeout(cmd_cnt->refcnt_wq,
+ percpu_ref_is_zero(&cmd_cnt->refcnt),
+ 180 * HZ);
} while (ret <= 0);
- wait_for_completion(&se_sess->stop_done);
+ wait_for_completion(&cmd_cnt->stop_done);
pr_debug("Waiting for cmds done.\n");
}
+
+/**
+ * target_wait_for_sess_cmds - Wait for outstanding commands
+ * @se_sess: session to wait for active I/O
+ */
+void target_wait_for_sess_cmds(struct se_session *se_sess)
+{
+ target_wait_for_cmds(se_sess->cmd_cnt);
+}
EXPORT_SYMBOL(target_wait_for_sess_cmds);
/*
diff --git a/include/target/iscsi/iscsi_target_core.h b/include/target/iscsi/iscsi_target_core.h
index 94d06ddfd80ad..229118156a1f6 100644
--- a/include/target/iscsi/iscsi_target_core.h
+++ b/include/target/iscsi/iscsi_target_core.h
@@ -600,6 +600,7 @@ struct iscsit_conn {
struct iscsi_tpg_np *tpg_np;
/* Pointer to parent session */
struct iscsit_session *sess;
+ struct target_cmd_counter *cmd_cnt;
int bitmap_id;
int rx_thread_active;
struct task_struct *rx_thread;
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index 12c9ba16217ef..bd299790e99c3 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -494,6 +494,7 @@ struct se_cmd {
struct se_lun *se_lun;
/* Only used for internal passthrough and legacy TCM fabric modules */
struct se_session *se_sess;
+ struct target_cmd_counter *cmd_cnt;
struct se_tmr_req *se_tmr_req;
struct llist_node se_cmd_list;
struct completion *free_compl;
@@ -619,22 +620,26 @@ static inline struct se_node_acl *fabric_stat_to_nacl(struct config_item *item)
acl_fabric_stat_group);
}
-struct se_session {
+struct target_cmd_counter {
+ struct percpu_ref refcnt;
+ wait_queue_head_t refcnt_wq;
+ struct completion stop_done;
atomic_t stopped;
+};
+
+struct se_session {
u64 sess_bin_isid;
enum target_prot_op sup_prot_ops;
enum target_prot_type sess_prot_type;
struct se_node_acl *se_node_acl;
struct se_portal_group *se_tpg;
void *fabric_sess_ptr;
- struct percpu_ref cmd_count;
struct list_head sess_list;
struct list_head sess_acl_list;
spinlock_t sess_cmd_lock;
- wait_queue_head_t cmd_count_wq;
- struct completion stop_done;
void *sess_cmd_map;
struct sbitmap_queue sess_tag_pool;
+ struct target_cmd_counter *cmd_cnt;
};
struct se_device;
