Michael> What about ib_umad_reg_agent error handling code in
Michael> ib_umad_reg_agent? That seems to still call
Michael> ib_umad_unreg_agent from under the down_write.
I'm pretty sure that's OK, because it's not possible for any send
requests to have been posted to that agent if we hit that error path.
Michael> And what about ib_umad_kill_port, which also does this?
That looks like a problem. I think we need the following (the locking
should still be OK, there's no need to do all the cleanup atomically).
--- infiniband/core/user_mad.c (revision 3989)
+++ infiniband/core/user_mad.c (working copy)
@@ -849,6 +849,7 @@ err_cdev:
static void ib_umad_kill_port(struct ib_umad_port *port)
{
struct ib_umad_file *file;
+ struct ib_mad_agent *agent;
int id;
class_set_devdata(port->class_dev, NULL);
@@ -865,19 +866,21 @@ static void ib_umad_kill_port(struct ib_
spin_unlock(&port_lock);
down_write(&port->mutex);
-
port->ib_dev = NULL;
+ up_write(&port->mutex);
list_for_each_entry(file, &port->file_list, port_list)
for (id = 0; id < IB_UMAD_MAX_AGENTS; ++id) {
- if (!file->agent[id])
- continue;
- ib_dereg_mr(file->mr[id]);
- ib_unregister_mad_agent(file->agent[id]);
+ down_write(&port->mutex);
+ agent = file->agent[id];
file->agent[id] = NULL;
- }
+ up_write(&port->mutex);
- up_write(&port->mutex);
+ if (agent) {
+ ib_unregister_mad_agent(agent);
+ ib_dereg_mr(file->mr[id]);
+ }
+ }
clear_bit(port->dev_num, dev_map);
}
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