The approach in the iSCSI target driver with regard to command
reference counting is as follows:
- When a command or TMF is submitted to the LIO core,
target_get_sess_cmd() is called with the second argument set
to true such that cmd_kref is initialized to two.
- During regular execution of a command target_put_sess_cmd() is
called once. However, if a connection is shut down it is not
sure that target_put_sess_cmd() has already been called.
- If the 'shutdown' argument of iscsit_free_cmd() is true, this
function is responsible for calling target_put_sess_cmd() if
that has not yet happened before that function was called.
Since it is not possible to determine whether or not
target_put_sess_cmd() has already been called by examining the
CMD_T_ABORTED flag and cmd_kref only (e.g. if a LUN RESET is in
progress concurrently with iscsit_free_cmd()), use the refcount
that was introduced by the previous patch to figure out whether
or not target_put_sess_cmd() has to be called from inside
iscsit_free_cmd().
Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
---
drivers/target/iscsi/iscsi_target_util.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/drivers/target/iscsi/iscsi_target_util.c b/drivers/target/iscsi/iscsi_target_util.c
index 1cacfe1003e3..04c7356e4402 100644
--- a/drivers/target/iscsi/iscsi_target_util.c
+++ b/drivers/target/iscsi/iscsi_target_util.c
@@ -770,12 +770,11 @@ void __iscsit_free_cmd(struct iscsi_cmd *cmd, bool check_queues)
void iscsit_free_cmd(struct iscsi_cmd *cmd, bool shutdown)
{
struct se_cmd *se_cmd = cmd->se_cmd.se_tfo ? &cmd->se_cmd : NULL;
- int rc;
__iscsit_free_cmd(cmd, shutdown);
if (se_cmd) {
- rc = transport_generic_free_cmd(&cmd->se_cmd, shutdown);
- if (!rc && shutdown && se_cmd && se_cmd->se_sess) {
+ transport_generic_free_cmd(&cmd->se_cmd, shutdown);
+ if (shutdown && atomic_read(&cmd->refcnt)) {
__iscsit_free_cmd(cmd, shutdown);
iscsit_put_cmd(cmd);
}
--
2.12.0
--
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