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| author | Gerd Hoffmann <kraxel@redhat.com> | 2020-09-07 13:24:25 +0200 |
|---|---|---|
| committer | Gerd Hoffmann <kraxel@redhat.com> | 2020-09-09 07:58:56 +0200 |
| commit | 707d561f77b5e2a6f90c9786bee44ee7a8dedc7e (patch) | |
| tree | 0d61c5038b1f4e8d9f5c0640b7349058600cb9d7 /drivers/gpu/drm/drm_prime.c | |
| parent | 04e89ff364dec3dc261243c2f0780635448bc466 (diff) | |
| download | lwn-707d561f77b5e2a6f90c9786bee44ee7a8dedc7e.tar.gz lwn-707d561f77b5e2a6f90c9786bee44ee7a8dedc7e.zip | |
drm: allow limiting the scatter list size.
Add drm_device argument to drm_prime_pages_to_sg(), so we can
call dma_max_mapping_size() to figure the segment size limit
and call into __sg_alloc_table_from_pages() with the correct
limit.
This fixes virtio-gpu with sev. Possibly it'll fix other bugs
too given that drm seems to totaly ignore segment size limits
so far ...
v2: place max_segment in drm driver not gem object.
v3: move max_segment next to the other gem fields.
v4: just use dma_max_mapping_size().
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20200907112425.15610-2-kraxel@redhat.com
Diffstat (limited to 'drivers/gpu/drm/drm_prime.c')
| -rw-r--r-- | drivers/gpu/drm/drm_prime.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c index 1693aa7c14b5..8a6a3c99b7d8 100644 --- a/drivers/gpu/drm/drm_prime.c +++ b/drivers/gpu/drm/drm_prime.c @@ -802,9 +802,11 @@ static const struct dma_buf_ops drm_gem_prime_dmabuf_ops = { * * This is useful for implementing &drm_gem_object_funcs.get_sg_table. */ -struct sg_table *drm_prime_pages_to_sg(struct page **pages, unsigned int nr_pages) +struct sg_table *drm_prime_pages_to_sg(struct drm_device *dev, + struct page **pages, unsigned int nr_pages) { struct sg_table *sg = NULL; + size_t max_segment = 0; int ret; sg = kmalloc(sizeof(struct sg_table), GFP_KERNEL); @@ -813,8 +815,13 @@ struct sg_table *drm_prime_pages_to_sg(struct page **pages, unsigned int nr_page goto out; } - ret = sg_alloc_table_from_pages(sg, pages, nr_pages, 0, - nr_pages << PAGE_SHIFT, GFP_KERNEL); + if (dev) + max_segment = dma_max_mapping_size(dev->dev); + if (max_segment == 0 || max_segment > SCATTERLIST_MAX_SEGMENT) + max_segment = SCATTERLIST_MAX_SEGMENT; + ret = __sg_alloc_table_from_pages(sg, pages, nr_pages, 0, + nr_pages << PAGE_SHIFT, + max_segment, GFP_KERNEL); if (ret) goto out; |