IB/isert: Fix incorrect release of isert connection

[ Upstream commit 699826f4 ]

The ib_isert module is releasing the isert connection both in
isert_wait_conn() handler as well as isert_free_conn() handler.
In isert_wait_conn() handler, it is expected to wait for iSCSI
session logout operation to complete. It should free the isert
connection only in isert_free_conn() handler.

When a bunch of iSER target is cleared, this issue can lead to
use-after-free memory issue as isert conn is twice released

Fixes: b02efbfc

 ("iser-target: Fix implicit termination of connections")
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Saravanan Vajravel <saravanan.vajravel@broadcom.com>
Signed-off-by: Selvin Xavier <selvin.xavier@broadcom.com>
Link: https://lore.kernel.org/r/20230606102531.162967-4-saravanan.vajravel@broadcom.com
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>