[PATCH 5.10 40/77] IB/hfi1: Fix abba locking issue with sc_disable()

Greg Kroah-Hartman
2021-11-01T09:38:14Z

From: Mike Marciniszyn <mike.marciniszyn@cornelisnetworks.com>

commit 13bac861952a78664907a0f927d3e874e9a59034 upstream.

sc_disable() after having disabled the send context wakes up any waiters
by calling hfi1_qp_wakeup() while holding the waitlock for the sc.

This is contrary to the model for all other calls to hfi1_qp_wakeup()
where the waitlock is dropped and a local is used to drive calls to
hfi1_qp_wakeup().

Fix by moving the sc->piowait into a local list and driving the wakeup
calls from the list.

Fixes: 099a884ba4c0 ("IB/hfi1: Handle wakeup of orphaned QPs for pio")
Link: https://lore.kernel.org/r/20211013141852.128104.2682.stgit@awfm-01.cornelisnetworks.com
Signed-off-by: Mike Marciniszyn <mike.marciniszyn@cornelisnetworks.com>
Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/infiniband/hw/hfi1/pio.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)

--- a/drivers/infiniband/hw/hfi1/pio.c
+++ b/drivers/infiniband/hw/hfi1/pio.c
@@ -920,6 +920,7 @@ void sc_disable(struct send_context *sc)
{
u64 reg;
struct pio_buf *pbuf;
+ LIST_HEAD(wake_list);

if (!sc)
return;
@@ -954,19 +955,21 @@ void sc_disable(struct send_context *sc)
spin_unlock(&sc->release_lock);

write_seqlock(&sc->waitlock);
- while (!list_empty(&sc->piowait)) {
+ if (!list_empty(&sc->piowait))
+ list_move(&sc->piowait, &wake_list);
+ write_sequnlock(&sc->waitlock);
+ while (!list_empty(&wake_list)) {
struct iowait *wait;
struct rvt_qp *qp;
struct hfi1_qp_priv *priv;

- wait = list_first_entry(&sc->piowait, struct iowait, list);
+ wait = list_first_entry(&wake_list, struct iowait, list);
qp = iowait_to_qp(wait);
priv = qp->priv;
list_del_init(&priv->s_iowait.list);
priv->s_iowait.lock = NULL;
hfi1_qp_wakeup(qp, RVT_S_WAIT_PIO | HFI1_S_WAIT_PIO_DRAIN);
}
- write_sequnlock(&sc->waitlock);

spin_unlock_irq(&sc->alloc_lock);
}