[PATCH] drm/amdgpu: don't increase UMC RAS UE count if no new bad page

[Tao Zhou]

If a UMC bad page is reserved but not freed by an application, the
application may trigger uncorrectable error repeatly by accessing the page.

Signed-off-by: Tao Zhou <tao.zhou1 at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c | 9 ++++++++-
 drivers/gpu/drm/amd/amdgpu/amdgpu_umc.c | 6 +++++-
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
index e85c4689ce2c..eafe01a24349 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ras.c
@@ -2049,7 +2049,7 @@ int amdgpu_ras_add_bad_pages(struct amdgpu_device *adev,
 {
 	struct amdgpu_ras *con = amdgpu_ras_get_context(adev);
 	struct ras_err_handler_data *data;
-	int ret = 0;
+	int ret = 0, old_cnt;
 	uint32_t i;
 
 	if (!con || !con->eh_data || !bps || pages <= 0)
@@ -2060,6 +2060,8 @@ int amdgpu_ras_add_bad_pages(struct amdgpu_device *adev,
 	if (!data)
 		goto out;
 
+	old_cnt = data->count;
+
 	for (i = 0; i < pages; i++) {
 		if (amdgpu_ras_check_bad_page_unlock(con,
 			bps[i].retired_page << AMDGPU_GPU_PAGE_SHIFT))
@@ -2079,6 +2081,11 @@ int amdgpu_ras_add_bad_pages(struct amdgpu_device *adev,
 		data->count++;
 		data->space_left--;
 	}
+
+	/* all pages have been reserved before, no new bad page */
+	if (old_cnt == data->count)
+		ret = -EEXIST;
+
 out:
 	mutex_unlock(&con->recovery_lock);
 
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_umc.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_umc.c
index 1c7fcb4f2380..772c431e4065 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_umc.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_umc.c
@@ -145,8 +145,12 @@ static int amdgpu_umc_do_page_retirement(struct amdgpu_device *adev,
 
 		if ((amdgpu_bad_page_threshold != 0) &&
 			err_data->err_addr_cnt) {
-			amdgpu_ras_add_bad_pages(adev, err_data->err_addr,
+			ret = amdgpu_ras_add_bad_pages(adev, err_data->err_addr,
 						err_data->err_addr_cnt);
+			/* if no new bad page is found, no need to increase ue count */
+			if (ret == -EEXIST)
+				err_data->ue_count = 0;
+
 			amdgpu_ras_save_bad_pages(adev);
 
 			amdgpu_dpm_send_hbm_bad_pages_num(adev, con->eeprom_control.ras_num_recs);
-- 
2.35.1