[PATCH 5.4 063/411] IB/rdmavt: add missing locks in rvt_ruc_loopback

Greg Kroah-Hartman
2022-06-13T11:07:10Z

From: Niels Dossche <dossche.niels@gmail.com>

[ Upstream commit 22cbc6c2681a0a4fe76150270426e763d52353a4 ]

The documentation of the function rvt_error_qp says both r_lock and
s_lock need to be held when calling that function.
It also asserts using lockdep that both of those locks are held.
rvt_error_qp is called form rvt_send_cq, which is called from
rvt_qp_complete_swqe, which is called from rvt_send_complete, which is
called from rvt_ruc_loopback in two places. Both of these places do not
hold r_lock. Fix this by acquiring a spin_lock of r_lock in both of
these places.
The r_lock acquiring cannot be added in rvt_qp_complete_swqe because
some of its other callers already have r_lock acquired.

Link: https://lore.kernel.org/r/20220228195144.71946-1-dossche.niels@gmail.com
Signed-off-by: Niels Dossche <dossche.niels@gmail.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/infiniband/sw/rdmavt/qp.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/infiniband/sw/rdmavt/qp.c b/drivers/infiniband/sw/rdmavt/qp.c
index 48e8612c1bc8..e97c13967174 100644
--- a/drivers/infiniband/sw/rdmavt/qp.c
+++ b/drivers/infiniband/sw/rdmavt/qp.c
@@ -2812,7 +2812,7 @@ void rvt_qp_iter(struct rvt_dev_info *rdi,
EXPORT_SYMBOL(rvt_qp_iter);

/*
- * This should be called with s_lock held.
+ * This should be called with s_lock and r_lock held.
*/
void rvt_send_complete(struct rvt_qp *qp, struct rvt_swqe *wqe,
enum ib_wc_status status)
@@ -3171,7 +3171,9 @@ void rvt_ruc_loopback(struct rvt_qp *sqp)
rvp->n_loop_pkts++;
flush_send:
sqp->s_rnr_retry = sqp->s_rnr_retry_cnt;
+ spin_lock(&sqp->r_lock);
rvt_send_complete(sqp, wqe, send_status);
+ spin_unlock(&sqp->r_lock);
if (local_ops) {
atomic_dec(&sqp->local_ops_pending);
local_ops = 0;
@@ -3225,7 +3227,9 @@ void rvt_ruc_loopback(struct rvt_qp *sqp)
spin_unlock_irqrestore(&qp->r_lock, flags);
serr_no_r_lock:
spin_lock_irqsave(&sqp->s_lock, flags);
+ spin_lock(&sqp->r_lock);
rvt_send_complete(sqp, wqe, send_status);
+ spin_unlock(&sqp->r_lock);
if (sqp->ibqp.qp_type == IB_QPT_RC) {
int lastwqe;

--
2.35.1