From 5c2fefd882d3666f11447e3e0fe663a8a7f64cc9 Mon Sep 17 00:00:00 2001
From: Alexey Kardashevskiy <aik@ozlabs.ru>
Date: Mon, 2 Oct 2017 12:39:11 -0600
Subject: vfio/spapr: Add cond_resched() for huge updates

Clearing very big IOMMU tables can trigger soft lockups. This adds
cond_resched() to allow the scheduler to do context switching when
it decides to.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---
 drivers/vfio/vfio_iommu_spapr_tce.c | 2 ++
 1 file changed, 2 insertions(+)

(limited to 'drivers/vfio/vfio_iommu_spapr_tce.c')

diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c
index 63112c36ab2d..759a5bdd40e1 100644
--- a/drivers/vfio/vfio_iommu_spapr_tce.c
+++ b/drivers/vfio/vfio_iommu_spapr_tce.c
@@ -507,6 +507,8 @@ static int tce_iommu_clear(struct tce_container *container,
 	enum dma_data_direction direction;
 
 	for ( ; pages; --pages, ++entry) {
+		cond_resched();
+
 		direction = DMA_NONE;
 		oldhpa = 0;
 		ret = iommu_tce_xchg(tbl, entry, &oldhpa, &direction);
-- 
cgit