[PATCH 1/2] drm/gpusvm: Limit the number of retries in drm_gpusvm_get_pages

[Matthew Brost <matthew.brost@intel.com>]

drm_gpusvm_get_pages should not be allowed to retry forever, cap the
time spent in the function to HMM_RANGE_DEFAULT_TIMEOUT has this is
essentially a wrapper around hmm_range_fault.

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
---
 drivers/gpu/drm/drm_gpusvm.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/drm_gpusvm.c b/drivers/gpu/drm/drm_gpusvm.c
index 73e550c8ff8c..39c8c50401dd 100644
--- a/drivers/gpu/drm/drm_gpusvm.c
+++ b/drivers/gpu/drm/drm_gpusvm.c
@@ -1288,6 +1288,9 @@ int drm_gpusvm_get_pages(struct drm_gpusvm *gpusvm,
 							   DMA_BIDIRECTIONAL;
 
 retry:
+	if (time_after(jiffies, timeout))
+		return -EBUSY;
+
 	hmm_range.notifier_seq = mmu_interval_read_begin(notifier);
 	if (drm_gpusvm_pages_valid_unlocked(gpusvm, svm_pages))
 		goto set_seqno;
-- 
2.34.1