From: Rick Farrington <ricardo.farrington@cavium.com>
Date: Tue, 28 Aug 2018 11:32:55 -0700
Subject: liquidio: fix race condition in instruction completion processing
Patch-mainline: v4.20-rc1
Git-commit: b943f17e06493fd2c7fd00743093ad5dcdb90e7f
References: bsc#1119406 FATE#326562

In lio_enable_irq, the pkt_in_done count register was being cleared to
zero.  However, there could be some completed instructions which were not
yet processed due to budget and limit constraints.
So, only write this register with the number of actual completions
that were processed.

Signed-off-by: Rick Farrington <ricardo.farrington@cavium.com>
Signed-off-by: Felix Manlunas <felix.manlunas@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/cavium/liquidio/octeon_device.c   |    5 +++--
 drivers/net/ethernet/cavium/liquidio/octeon_iq.h       |    2 ++
 drivers/net/ethernet/cavium/liquidio/request_manager.c |    2 ++
 3 files changed, 7 insertions(+), 2 deletions(-)

--- a/drivers/net/ethernet/cavium/liquidio/octeon_device.c
+++ b/drivers/net/ethernet/cavium/liquidio/octeon_device.c
@@ -1450,8 +1450,9 @@ void lio_enable_irq(struct octeon_droq *
 	}
 	if (iq) {
 		spin_lock_bh(&iq->lock);
-		writel(iq->pkt_in_done, iq->inst_cnt_reg);
-		iq->pkt_in_done = 0;
+		writel(iq->pkts_processed, iq->inst_cnt_reg);
+		iq->pkt_in_done -= iq->pkts_processed;
+		iq->pkts_processed = 0;
 		/* this write needs to be flushed before we release the lock */
 		mmiowb();
 		spin_unlock_bh(&iq->lock);
--- a/drivers/net/ethernet/cavium/liquidio/octeon_iq.h
+++ b/drivers/net/ethernet/cavium/liquidio/octeon_iq.h
@@ -94,6 +94,8 @@ struct octeon_instr_queue {
 
 	u32 pkt_in_done;
 
+	u32 pkts_processed;
+
 	/** A spinlock to protect access to the input ring.*/
 	spinlock_t iq_flush_running_lock;
 
--- a/drivers/net/ethernet/cavium/liquidio/request_manager.c
+++ b/drivers/net/ethernet/cavium/liquidio/request_manager.c
@@ -122,6 +122,7 @@ int octeon_init_instr_queue(struct octeo
 	iq->do_auto_flush = 1;
 	iq->db_timeout = (u32)conf->db_timeout;
 	atomic_set(&iq->instr_pending, 0);
+	iq->pkts_processed = 0;
 
 	/* Initialize the spinlock for this instruction queue */
 	spin_lock_init(&iq->lock);
@@ -494,6 +495,7 @@ octeon_flush_iq(struct octeon_device *oc
 				lio_process_iq_request_list(oct, iq, 0);
 
 		if (inst_processed) {
+			iq->pkts_processed += inst_processed;
 			atomic_sub(inst_processed, &iq->instr_pending);
 			iq->stats.instr_processed += inst_processed;
 		}