Messages in this thread | | | Subject | Re: [PATCH 01/13] drm/exynos: Stop using frame_vector helpers | From | John Hubbard <> | Date | Wed, 7 Oct 2020 14:36:52 -0700 |
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On 10/7/20 2:32 PM, Daniel Vetter wrote: > On Wed, Oct 7, 2020 at 10:33 PM John Hubbard <jhubbard@nvidia.com> wrote: >> >> On 10/7/20 9:44 AM, Daniel Vetter wrote: ... >>> @@ -398,15 +399,11 @@ static void g2d_userptr_put_dma_addr(struct g2d_data *g2d, >>> dma_unmap_sgtable(to_dma_dev(g2d->drm_dev), g2d_userptr->sgt, >>> DMA_BIDIRECTIONAL, 0); >>> >>> - pages = frame_vector_pages(g2d_userptr->vec); >>> - if (!IS_ERR(pages)) { >>> - int i; >>> + for (i = 0; i < g2d_userptr->npages; i++) >>> + set_page_dirty_lock(g2d_userptr->pages[i]); >>> >>> - for (i = 0; i < frame_vector_count(g2d_userptr->vec); i++) >>> - set_page_dirty_lock(pages[i]); >>> - } >>> - put_vaddr_frames(g2d_userptr->vec); >>> - frame_vector_destroy(g2d_userptr->vec); >>> + unpin_user_pages(g2d_userptr->pages, g2d_userptr->npages); >>> + kvfree(g2d_userptr->pages); >> >> You can avoid writing your own loop, and just simplify the whole thing down to >> two lines: >> >> unpin_user_pages_dirty_lock(g2d_userptr->pages, g2d_userptr->npages, >> true); >> kvfree(g2d_userptr->pages); > > Oh nice, this is neat. I'll also roll it out in the habanalabs patch, > that has the same thing. Well almost, it only uses set_page_dirty, not > the _lock variant. But I have no idea whether that matters or not?
It matters. And invariably, call sites that use set_page_dirty() instead of set_page_dirty_lock() were already wrong. Which is why I never had to provide anything like "unpin_user_pages_dirty (not locked)".
Although in habanalabs case, I just reviewed patch 3 and I think they *were* correctly using set_page_dirty_lock()...
thanks, -- John Hubbard NVIDIA
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