[PATCH] drm/amdgpu: move notifier_seq read back inside retry loop

[Honglei Huang]

Align with drm_gpusvm_get_pages() (drm_gpusvm.c line 1416, 1440) which
refreshes notifier_seq via mmu_interval_read_begin() on each retry
iteration. Without this, a stale sequence number causes
hmm_range_fault() to perpetually return -EBUSY, leading to an infinite
retry loop at the caller level.

Fixes: 144ba981783f ("drm/amdgpu: fix amdgpu_hmm_range_get_pages")
Signed-off-by: Honglei Huang <hongh...@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
index 5d72878c8..ec0fe9044 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_hmm.c
@@ -192,7 +192,6 @@ int amdgpu_hmm_range_get_pages(struct mmu_interval_notifier 
*notifier,
        end = start + npages * PAGE_SIZE;
        hmm_range->dev_private_owner = owner;
 
-       hmm_range->notifier_seq = mmu_interval_read_begin(notifier);
        do {
                hmm_range->end = min(hmm_range->start + max_bytes, end);
 
@@ -202,6 +201,7 @@ int amdgpu_hmm_range_get_pages(struct mmu_interval_notifier 
*notifier,
                timeout = jiffies + msecs_to_jiffies(HMM_RANGE_DEFAULT_TIMEOUT);
 
 retry:
+               hmm_range->notifier_seq = mmu_interval_read_begin(notifier);
                r = hmm_range_fault(hmm_range);
                if (unlikely(r)) {
                        if (r == -EBUSY && !time_after(jiffies, timeout))
-- 
2.34.1