On 6/9/20 7:21 PM, Koenig, Christian wrote:
Am 09.06.2020 18:37 schrieb "Grodzovsky, Andrey" <andrey.grodzov...@amd.com>:On 6/5/20 2:40 PM, Christian König wrote: > Am 05.06.20 um 16:29 schrieb Andrey Grodzovsky: >> >> On 5/11/20 2:45 AM, Christian König wrote: >>> Am 09.05.20 um 20:51 schrieb Andrey Grodzovsky: >>>> Signed-off-by: Andrey Grodzovsky <andrey.grodzov...@amd.com> >>>> --- >>>> drivers/gpu/drm/ttm/ttm_bo.c | 22 +++++++++++++++++++++- >>>> include/drm/ttm/ttm_bo_driver.h | 2 ++ >>>> 2 files changed, 23 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/drivers/gpu/drm/ttm/ttm_bo.c >>>> b/drivers/gpu/drm/ttm/ttm_bo.c >>>> index c5b516f..eae61cc 100644 >>>> --- a/drivers/gpu/drm/ttm/ttm_bo.c >>>> +++ b/drivers/gpu/drm/ttm/ttm_bo.c >>>> @@ -1750,9 +1750,29 @@ void ttm_bo_unmap_virtual(struct >>>> ttm_buffer_object *bo) >>>> ttm_bo_unmap_virtual_locked(bo); >>>> ttm_mem_io_unlock(man); >>>> } >>>> +EXPORT_SYMBOL(ttm_bo_unmap_virtual); >>>> +void ttm_bo_unmap_virtual_address_space(struct ttm_bo_device *bdev) >>>> +{ >>>> + struct ttm_mem_type_manager *man; >>>> + int i; >>>> -EXPORT_SYMBOL(ttm_bo_unmap_virtual); >>> >>>> + for (i = 0; i < TTM_NUM_MEM_TYPES; i++) { >>>> + man = &bdev->man[i]; >>>> + if (man->has_type && man->use_type) >>>> + ttm_mem_io_lock(man, false); >>>> + } >>> >>> You should drop that it will just result in a deadlock warning for >>> Nouveau and has no effect at all. >>> >>> Apart from that looks good to me, >>> Christian. >> >> >> As I am considering to re-include this in V2 of the patchsets, can >> you clarify please why this will have no effect at all ? > > The locks are exclusive for Nouveau to allocate/free the io address > space. > > Since we don't do this here we don't need the locks. > > Christian. So basically calling unmap_mapping_range doesn't require any extra locking around it and whatever locks are taken within the function should be enough ? I think so, yes. Christian.
Yes, that's true. However, without the bo reservation, nothing stops a PTE from being immediately re-faulted back again. Even while unmap_mapping_range() is running. So the device removed flag needs to be advertized before this function is run, (perhaps with a memory barrier pair). That should probably be added to the function documentation.
(Other than that, please add a commit message if respinning). /Thomas
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