Re: [PATCH V1] accel/amdxdna: Add BO import and export

[Lizhi Hou]

Hi Jeff,


Just noticed that the driver should not use import_attach. 
https://lore.kernel.org/all/20250317131923.238374-1-tzimmermann@xxxxxxx/

I will remove the import_attach usage and send V3 patch.


Thanks

Lizhi

On 3/21/25 12:52, Lizhi Hou wrote:
> On 3/21/25 08:15, Jeff Hugo wrote:
> > On 3/6/2025 11:03 AM, Lizhi Hou wrote:
> > > +struct drm_gem_object *
> > > +amdxdna_gem_prime_import(struct drm_device *dev, struct dma_buf 
> > > *dma_buf)
> > > +{
> > > +    struct dma_buf_attachment *attach;
> > > +    struct drm_gem_object *gobj;
> > > +    struct sg_table *sgt;
> > > +    int ret;
> > > +
> > > +    attach = dma_buf_attach(dma_buf, dev->dev);
> > > +    if (IS_ERR(attach))
> > > +        return ERR_CAST(attach);
> > > +
> > > +    get_dma_buf(dma_buf);
> > > +
> > > +    sgt = dma_buf_map_attachment_unlocked(attach, DMA_BIDIRECTIONAL);
> > > +    if (IS_ERR(sgt)) {
> > > +        ret = PTR_ERR(sgt);
> > > +        goto fail_detach;
> > > +    }
> > > +
> > > +    gobj = drm_gem_shmem_prime_import_sg_table(dev, attach, sgt);
> > > +    if (IS_ERR(gobj)) {
> > > +        ret = PTR_ERR(gobj);
> > > +        goto fail_unmap;
> > > +    }
> > > +
> > > +    gobj->import_attach = attach;
> > > +    gobj->resv = dma_buf->resv;
> > > +
> > > +    return gobj;
> > > +
> > > +fail_unmap:
> > > +    dma_buf_unmap_attachment_unlocked(attach, sgt, DMA_BIDIRECTIONAL);
> > > +fail_detach:
> > > +    dma_buf_detach(dma_buf, attach);
> > > +    dma_buf_put(dma_buf);
> >
> > You attach() and then get(), so normal "reverse order" cleanup would 
> > be put(), then detach(). That is not what you do here. Should this be 
> > reordered, or should you get() then attach() first?
>
> I referred drm_gem_prime_import_dev(). And I agree with you. It looks 
> better to get() before attach(). I will respin V2 which will also 
> contain another small update for this patch.
>
>
> Thanks,
>
> Lizhi
>
> >