RDMA/rtrs-srv: Use sysfs_remove_file_self for disconnect

Remove self first to avoid deadlock, we don't want to
use close_work to remove sess sysfs.

Fixes: 91b11610 ("RDMA/rtrs: server: sysfs interface functions")
Link: https://lore.kernel.org/r/20201217141915.56989-5-jinpu.wang@cloud.ionos.comSigned-off-by: Jack Wang <jinpu.wang@cloud.ionos.com>
Tested-by: Lutz Pogrell <lutz.pogrell@cloud.ionos.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>

drivers/infiniband/ulp/rtrs/rtrs-srv-sysfs.c

@@ -51,6 +51,8 @@ static ssize_t rtrs_srv_disconnect_store(struct kobject *kobj,
 	sockaddr_to_str((struct sockaddr *)&sess->s.dst_addr, str, sizeof(str));
 
 	rtrs_info(s, "disconnect for path %s requested\n", str);
+	/* first remove sysfs itself to avoid deadlock */
+	sysfs_remove_file_self(&sess->kobj, &attr->attr);
 	close_sess(sess);
 
 	return count;