iser_initialize_task_headers() uses in_interrupt() to find out if it is
safe to acquire a mutex.
in_interrupt() is deprecated as it is ill defined and does not provide what
it suggests. Aside of that it covers only parts of the contexts in which
a mutex may not be acquired.
The following callchains exist:
iscsi_queuecommand() *locks* iscsi_session::frwd_lock
-> iscsi_prep_scsi_cmd_pdu()
-> session->tt->init_task() (iscsi_iser_task_init())
-> iser_initialize_task_headers()
-> iscsi_iser_task_xmit() (iscsi_transport::xmit_task)
-> iscsi_iser_task_xmit_unsol_data()
-> iser_send_data_out()
-> iser_initialize_task_headers()
iscsi_data_xmit() *locks* iscsi_session::frwd_lock
-> iscsi_prep_mgmt_task()
-> session->tt->init_task() (iscsi_iser_task_init())
-> iser_initialize_task_headers()
-> iscsi_prep_scsi_cmd_pdu()
-> session->tt->init_task() (iscsi_iser_task_init())
-> iser_initialize_task_headers()
__iscsi_conn_send_pdu() caller has iscsi_session::frwd_lock
-> iscsi_prep_mgmt_task()
-> session->tt->init_task() (iscsi_iser_task_init())
-> iser_initialize_task_headers()
-> session->tt->xmit_task() (
The only callchain that is close to be invoked in preemptible context:
iscsi_xmitworker() worker
-> iscsi_data_xmit()
-> iscsi_xmit_task()
-> conn->session->tt->xmit_task() (iscsi_iser_task_xmit()
In iscsi_iser_task_xmit() there is this check:
if (!task->sc)
return iscsi_iser_mtask_xmit(conn, task);
so it does end up in iser_initialize_task_headers() and
iser_initialize_task_headers() relies on iscsi_task::sc == NULL.
Remove conditional locking of iser_conn::state_mutex because there is no
call chain to do so.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Sagi Grimberg <sagi@xxxxxxxxxxx>
Cc: Max Gurtovoy <maxg@xxxxxxxxxx>
Cc: Doug Ledford <dledford@xxxxxxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxx>
---
drivers/infiniband/ulp/iser/iscsi_iser.c | 7 -------
1 file changed, 7 deletions(-)
diff --git a/drivers/infiniband/ulp/iser/iscsi_iser.c b/drivers/infiniband/ulp/iser/iscsi_iser.c
index 3690e28cc7ea2..b34a1881c4cad 100644
--- a/drivers/infiniband/ulp/iser/iscsi_iser.c
+++ b/drivers/infiniband/ulp/iser/iscsi_iser.c
@@ -187,12 +187,8 @@ iser_initialize_task_headers(struct iscsi_task *task,
struct iser_device *device = iser_conn->ib_conn.device;
struct iscsi_iser_task *iser_task = task->dd_data;
u64 dma_addr;
- const bool mgmt_task = !task->sc && !in_interrupt();
int ret = 0;
- if (unlikely(mgmt_task))
- mutex_lock(&iser_conn->state_mutex);
-
if (unlikely(iser_conn->state != ISER_CONN_UP)) {
ret = -ENODEV;
goto out;
@@ -215,9 +211,6 @@ iser_initialize_task_headers(struct iscsi_task *task,
iser_task->iser_conn = iser_conn;
out:
- if (unlikely(mgmt_task))
- mutex_unlock(&iser_conn->state_mutex);
-
return ret;
}
--
2.29.2
