Hi Christian,
If " tmo = dma_fence_wait_timeout(fence, false, tmo); " was executed inside list_for_each_entry, the value of tmo might be changed.
But " tmo = dma_fence_wait_timeout(fence, false, tmo); " might be called after exiting the loop of list_for_each_entry.
It might pass a different value of tmo into dma_fence_wait_timeout.
BR,
Wentao
-----Original Message-----
From: Christian König <ckoenig.leichtzumerken@xxxxxxxxx>
Sent: Tuesday, April 2, 2019 3:01 PM
To: Deng, Emily <Emily.Deng@xxxxxxx>; Lou, Wentao <Wentao.Lou@xxxxxxx>; amd-gfx@xxxxxxxxxxxxxxxxxxxxx
Subject: Re: [PATCH] drm/amdgpu: amdgpu_device_recover_vram always failed if only one node in shadow_list
Yeah, agree that is much closer to a correct solution.
But even better would be to correctly update the timeout as well, e.g:
tmo = dma_fence_wait_timeout(fence, false, tmo); dma_fence_put(fence); fence = next; if (tmo == 0)
r = -ETIMEDOUT;
break
} else if (tmo < 0) {
r = tmo;
break;
}
That we restart the timeout for each wait looks like a rather problematic bug to me as well.
Christian.
Am 02.04.19 um 06:03 schrieb Deng, Emily:
> Maybe it will be better to add follow check, and change “if (r <= 0 || tmo <= 0) " to "if (r <0 || tmo <= 0)".
> r = dma_fence_wait_timeout(f, false, timeout);
> if (r == 0) {
> r = -ETIMEDOUT;
> break;
> } else if (r < 0) {
> break;
> }
>
> Best wishes
> Emily Deng
>
>
>> -----Original Message-----
>> From: amd-gfx <amd-gfx-bounces@xxxxxxxxxxxxxxxxxxxxx> On Behalf Of
>> wentalou
>> Sent: Monday, April 1, 2019 4:59 PM
>> To: amd-gfx@xxxxxxxxxxxxxxxxxxxxx
>> Cc: Lou, Wentao <Wentao.Lou@xxxxxxx>
>> Subject: [PATCH] drm/amdgpu: amdgpu_device_recover_vram always failed
>> if only one node in shadow_list
>>
>> amdgpu_bo_restore_shadow would assign zero to r if succeeded.
>> r would remain zero if there is only one node in shadow_list.
>> current code would always return failure when r <= 0.
>>
>> Change-Id: Iae6880e7c78b71fde6a6754c69665c2e312a80a5
>> Signed-off-by: Wentao Lou <Wentao.Lou@xxxxxxx>
>> ---
>> drivers/gpu/drm/amd/amdgpu/amdgpu_device.c | 6 +++++-
>> 1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> index c4c61e9..5cf21a4 100644
>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_device.c
>> @@ -3171,6 +3171,7 @@ static int amdgpu_device_recover_vram(struct
>> amdgpu_device *adev)
>> struct dma_fence *fence = NULL, *next = NULL;
>> struct amdgpu_bo *shadow;
>> long r = 1, tmo;
>> + bool single_shadow = false;
>>
>> if (amdgpu_sriov_runtime(adev))
>> tmo = msecs_to_jiffies(8000);
>> @@ -3194,10 +3195,12 @@ static int amdgpu_device_recover_vram(struct
>> amdgpu_device *adev)
>> r = dma_fence_wait_timeout(fence, false, tmo);
>> dma_fence_put(fence);
>> fence = next;
>> + single_shadow = false;
>> if (r <= 0)
>> break;
>> } else {
>> fence = next;
>> + single_shadow = true;
>> }
>> }
>> mutex_unlock(&adev->shadow_list_lock);
>> @@ -3206,7 +3209,8 @@ static int amdgpu_device_recover_vram(struct
>> amdgpu_device *adev)
>> tmo = dma_fence_wait_timeout(fence, false, tmo);
>> dma_fence_put(fence);
>>
>> - if (r <= 0 || tmo <= 0) {
>> + /* r would be zero even if amdgpu_bo_restore_shadow succeeded when
>> single shadow in list */
>> + if (r < 0 || (r == 0 && !single_shadow) || tmo <= 0) {
>> DRM_ERROR("recover vram bo from shadow failed\n");
>> return -EIO;
>> }
>> --
>> 2.7.4
>>
>> _______________________________________________
>> amd-gfx mailing list
>> amd-gfx@xxxxxxxxxxxxxxxxxxxxx
>> https://lists.freedesktop.org/mailman/listinfo/amd-gfx
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