From: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
This patch moves target_put_sess_cmd() to use a se_cmd->cmd_kref
callback target_release_cmd_kref when performing driver release of
fabric->se_cmd descriptor memory. It sets the default cmd_kref
count value to '2' within target_get_sess_cmd() setup, and
currently assumes TFO->check_stop_free() usage.
It drops se_tfo->check_release_cmd() usage in the main
transport_release_cmd codepath.
Cc: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Nicholas Bellinger <nab@xxxxxxxxxxxxxxx>
---
drivers/target/target_core_transport.c | 43 +++++++++++++++++++------------
include/target/target_core_base.h | 1 +
2 files changed, 27 insertions(+), 17 deletions(-)
diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index ab8473e..203d386 100644
--- a/drivers/target/target_core_transport.c
+++ b/drivers/target/target_core_transport.c
@@ -3888,13 +3888,13 @@ void transport_release_cmd(struct se_cmd *cmd)
if (cmd->t_task_cdb != cmd->__t_task_cdb)
kfree(cmd->t_task_cdb);
/*
- * Check if target_wait_for_sess_cmds() is expecting to
- * release se_cmd directly here..
+ * If this cmd has been setup with target_get_sess_cmd(), drop
+ * the kref and call ->release_cmd() in kref callback.
*/
- if (cmd->check_release != 0 && cmd->se_tfo->check_release_cmd)
- if (cmd->se_tfo->check_release_cmd(cmd) != 0)
- return;
-
+ if (cmd->check_release != 0) {
+ target_put_sess_cmd(cmd->se_sess, cmd);
+ return;
+ }
cmd->se_tfo->release_cmd(cmd);
}
EXPORT_SYMBOL(transport_release_cmd);
@@ -3930,6 +3930,9 @@ void target_get_sess_cmd(struct se_session *se_sess, struct se_cmd *se_cmd)
{
unsigned long flags;
+ kref_init(&se_cmd->cmd_kref);
+ kref_get(&se_cmd->cmd_kref);
+
spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
list_add_tail(&se_cmd->se_cmd_list, &se_sess->sess_cmd_list);
se_cmd->check_release = 1;
@@ -3937,30 +3940,36 @@ void target_get_sess_cmd(struct se_session *se_sess, struct se_cmd *se_cmd)
}
EXPORT_SYMBOL(target_get_sess_cmd);
-/* target_put_sess_cmd - Check for active I/O shutdown or list delete
- * @se_sess: session to reference
- * @se_cmd: command descriptor to drop
- */
-int target_put_sess_cmd(struct se_session *se_sess, struct se_cmd *se_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;
unsigned long flags;
spin_lock_irqsave(&se_sess->sess_cmd_lock, flags);
if (list_empty(&se_cmd->se_cmd_list)) {
spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
WARN_ON(1);
- return 0;
+ return;
}
-
if (se_sess->sess_tearing_down && se_cmd->cmd_wait_set) {
spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
- complete(&se_cmd->cmd_wait_comp);
- return 1;
+ complete(&se_cmd->cmd_wait_comp);
+ return;
}
list_del(&se_cmd->se_cmd_list);
spin_unlock_irqrestore(&se_sess->sess_cmd_lock, flags);
-
- return 0;
+
+ se_cmd->se_tfo->release_cmd(se_cmd);
+}
+
+/* target_put_sess_cmd - Check for active I/O shutdown via kref_put
+ * @se_sess: session to reference
+ * @se_cmd: command descriptor to drop
+ */
+int target_put_sess_cmd(struct se_session *se_sess, struct se_cmd *se_cmd)
+{
+ return kref_put(&se_cmd->cmd_kref, target_release_cmd_kref);
}
EXPORT_SYMBOL(target_put_sess_cmd);
diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index 79ac1fb..d5e3312 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -453,6 +453,7 @@ struct se_cmd {
struct list_head se_queue_node;
struct list_head se_cmd_list;
struct completion cmd_wait_comp;
+ struct kref cmd_kref;
struct target_core_fabric_ops *se_tfo;
int (*execute_task)(struct se_task *);
void (*transport_complete_callback)(struct se_cmd *);
--
1.7.2.5
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