6.11-stable review patch. If anyone has any objections, please let me know.
------------------
From: Selvin Xavier <selvin.xavier@xxxxxxxxxxxx>
[ Upstream commit 8be3e5b0c96beeefe9d5486b96575d104d3e7d17 ]
Driver waits indefinitely for the fifo occupancy to go below a threshold
as soon as the pacing interrupt is received. This can cause soft lockup on
one of the processors, if the rate of DB is very high.
Add a loop count for FPGA and exit the __wait_for_fifo_occupancy_below_th
if the loop is taking more time. Pacing will be continuing until the
occupancy is below the threshold. This is ensured by the checks in
bnxt_re_pacing_timer_exp and further scheduling the work for pacing based
on the fifo occupancy.
Fixes: 2ad4e6303a6d ("RDMA/bnxt_re: Implement doorbell pacing algorithm")
Link: https://patch.msgid.link/r/1728373302-19530-7-git-send-email-selvin.xavier@xxxxxxxxxxxx
Reviewed-by: Kalesh AP <kalesh-anakkur.purayil@xxxxxxxxxxxx>
Reviewed-by: Chandramohan Akula <chandramohan.akula@xxxxxxxxxxxx>
Signed-off-by: Selvin Xavier <selvin.xavier@xxxxxxxxxxxx>
Signed-off-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/infiniband/hw/bnxt_re/main.c | 9 +++++++++
1 file changed, 9 insertions(+)
diff --git a/drivers/infiniband/hw/bnxt_re/main.c b/drivers/infiniband/hw/bnxt_re/main.c
index e06adb2dfe6f9..c905a51aabfba 100644
--- a/drivers/infiniband/hw/bnxt_re/main.c
+++ b/drivers/infiniband/hw/bnxt_re/main.c
@@ -518,6 +518,7 @@ static bool is_dbr_fifo_full(struct bnxt_re_dev *rdev)
static void __wait_for_fifo_occupancy_below_th(struct bnxt_re_dev *rdev)
{
struct bnxt_qplib_db_pacing_data *pacing_data = rdev->qplib_res.pacing_data;
+ u32 retry_fifo_check = 1000;
u32 fifo_occup;
/* loop shouldn't run infintely as the occupancy usually goes
@@ -531,6 +532,14 @@ static void __wait_for_fifo_occupancy_below_th(struct bnxt_re_dev *rdev)
if (fifo_occup < pacing_data->pacing_th)
break;
+ if (!retry_fifo_check--) {
+ dev_info_once(rdev_to_dev(rdev),
+ "%s: fifo_occup = 0x%xfifo_max_depth = 0x%x pacing_th = 0x%x\n",
+ __func__, fifo_occup, pacing_data->fifo_max_depth,
+ pacing_data->pacing_th);
+ break;
+ }
+
}
}
--
2.43.0
