From: Krishnamraju Eraparaju <krishna2@xxxxxxxxxxx>
commit d219face9059f38ad187bde133451a2a308fdb7c upstream.
As per draft-hilland-iwarp-verbs-v1.0, sec 6.2.3, always initiate a CLOSE
when entering into TERM state.
In c4iw_modify_qp(), disconnect operation should only be performed when
the modify_qp call is invoked from ib_core. And all other internal
modify_qp calls(invoked within iw_cxgb4) that needs 'disconnect' should
call c4iw_ep_disconnect() explicitly after modify_qp. Otherwise, deadlocks
like below can occur:
Call Trace:
schedule+0x2f/0xa0
schedule_preempt_disabled+0xa/0x10
__mutex_lock.isra.5+0x2d0/0x4a0
c4iw_ep_disconnect+0x39/0x430 => tries to reacquire ep lock again
c4iw_modify_qp+0x468/0x10d0
rx_data+0x218/0x570 => acquires ep lock
process_work+0x5f/0x70
process_one_work+0x1a7/0x3b0
worker_thread+0x30/0x390
kthread+0x112/0x130
ret_from_fork+0x35/0x40
Fixes: d2c33370ae73 ("RDMA/iw_cxgb4: Always disconnect when QP is transitioning to TERMINATE state")
Link: https://lore.kernel.org/r/20200204091230.7210-1-krishna2@xxxxxxxxxxx
Signed-off-by: Krishnamraju Eraparaju <krishna2@xxxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/infiniband/hw/cxgb4/cm.c | 4 ++++
drivers/infiniband/hw/cxgb4/qp.c | 4 ++--
2 files changed, 6 insertions(+), 2 deletions(-)
--- a/drivers/infiniband/hw/cxgb4/cm.c
+++ b/drivers/infiniband/hw/cxgb4/cm.c
@@ -3036,6 +3036,10 @@ static int terminate(struct c4iw_dev *de
C4IW_QP_ATTR_NEXT_STATE, &attrs, 1);
}
+ /* As per draft-hilland-iwarp-verbs-v1.0, sec 6.2.3,
+ * when entering the TERM state the RNIC MUST initiate a CLOSE.
+ */
+ c4iw_ep_disconnect(ep, 1, GFP_KERNEL);
c4iw_put_ep(&ep->com);
} else
pr_warn("TERM received tid %u no ep/qp\n", tid);
--- a/drivers/infiniband/hw/cxgb4/qp.c
+++ b/drivers/infiniband/hw/cxgb4/qp.c
@@ -1948,10 +1948,10 @@ int c4iw_modify_qp(struct c4iw_dev *rhp,
qhp->attr.layer_etype = attrs->layer_etype;
qhp->attr.ecode = attrs->ecode;
ep = qhp->ep;
- c4iw_get_ep(&ep->com);
- disconnect = 1;
if (!internal) {
+ c4iw_get_ep(&ep->com);
terminate = 1;
+ disconnect = 1;
} else {
terminate = qhp->attr.send_term;
ret = rdma_fini(rhp, qhp, ep);
