Re: [PATCH v3 5/9] xen/gntdev: Allow mappings for DMA buffers

[Oleksandr Andrushchenko]

On 06/13/2018 04:26 AM, Boris Ostrovsky wrote:
> On 06/12/2018 09:41 AM, Oleksandr Andrushchenko wrote:
>
> > Â Â static void gntdev_print_maps(struct gntdev_priv *priv,
> > @@ -121,8 +146,27 @@ static void gntdev_free_map(struct grant_map *map)
> > ÂÂÂÂÂ if (map == NULL)
> > ÂÂÂÂÂÂÂÂÂ return;
> > Â +#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
> > +ÂÂÂ if (map->dma_vaddr) {
> > +ÂÂÂÂÂÂÂ struct gnttab_dma_alloc_args args;
> > +
> > +ÂÂÂÂÂÂÂ args.dev = map->dma_dev;
> > +ÂÂÂÂÂÂÂ args.coherent = map->dma_flags & GNTDEV_DMA_FLAG_COHERENT;
>
>
> args.coherent = !!(map->dma_flags & GNTDEV_DMA_FLAG_COHERENT);
Will fix
> > +ÂÂÂÂÂÂÂ args.nr_pages = map->count;
> > +ÂÂÂÂÂÂÂ args.pages = map->pages;
> > +ÂÂÂÂÂÂÂ args.frames = map->frames;
> > +ÂÂÂÂÂÂÂ args.vaddr = map->dma_vaddr;
> > +ÂÂÂÂÂÂÂ args.dev_bus_addr = map->dma_bus_addr;
> > +
> > +ÂÂÂÂÂÂÂ gnttab_dma_free_pages(&args);
> > +ÂÂÂ } else
> > +#endif
> > ÂÂÂÂÂ if (map->pages)
> > ÂÂÂÂÂÂÂÂÂ gnttab_free_pages(map->count, map->pages);
> > +
> > +#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
> > +ÂÂÂ kfree(map->frames);
> > +#endif
> > ÂÂÂÂÂ kfree(map->pages);
> > ÂÂÂÂÂ kfree(map->grants);
> > ÂÂÂÂÂ kfree(map->map_ops);
> > @@ -132,7 +176,8 @@ static void gntdev_free_map(struct grant_map *map)
> > ÂÂÂÂÂ kfree(map);
> > Â }
> > Â -static struct grant_map *gntdev_alloc_map(struct gntdev_priv 
> > *priv, int count)
> > +static struct grant_map *gntdev_alloc_map(struct gntdev_priv *priv, 
> > int count,
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ int dma_flags)
> > Â {
> > ÂÂÂÂÂ struct grant_map *add;
> > ÂÂÂÂÂ int i;
> > @@ -155,6 +200,37 @@ static struct grant_map *gntdev_alloc_map(struct 
> > gntdev_priv *priv, int count)
> > ÂÂÂÂÂÂÂÂÂ NULL == add->pages)
> > ÂÂÂÂÂÂÂÂÂ goto err;
> > Â +#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
> > +ÂÂÂ add->dma_flags = dma_flags;
> > +
> > +ÂÂÂ /*
> > +ÂÂÂÂ * Check if this mapping is requested to be backed
> > +ÂÂÂÂ * by a DMA buffer.
> > +ÂÂÂÂ */
> > +ÂÂÂ if (dma_flags & (GNTDEV_DMA_FLAG_WC | GNTDEV_DMA_FLAG_COHERENT)) {
> > +ÂÂÂÂÂÂÂ struct gnttab_dma_alloc_args args;
> > +
> > +ÂÂÂÂÂÂÂ add->frames = kcalloc(count, sizeof(add->frames[0]),
> > +ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ GFP_KERNEL);
> > +ÂÂÂÂÂÂÂ if (!add->frames)
> > +ÂÂÂÂÂÂÂÂÂÂÂ goto err;
> > +
> > +ÂÂÂÂÂÂÂ /* Remember the device, so we can free DMA memory. */
> > +ÂÂÂÂÂÂÂ add->dma_dev = priv->dma_dev;
> > +
> > +ÂÂÂÂÂÂÂ args.dev = priv->dma_dev;
> > +ÂÂÂÂÂÂÂ args.coherent = dma_flags & GNTDEV_DMA_FLAG_COHERENT;
>
>
> And again here.
Will fix
> > +ÂÂÂÂÂÂÂ args.nr_pages = count;
> > +ÂÂÂÂÂÂÂ args.pages = add->pages;
> > +ÂÂÂÂÂÂÂ args.frames = add->frames;
> > +
> > +ÂÂÂÂÂÂÂ if (gnttab_dma_alloc_pages(&args))
> > +ÂÂÂÂÂÂÂÂÂÂÂ goto err;
> > +
> > +ÂÂÂÂÂÂÂ add->dma_vaddr = args.vaddr;
> > +ÂÂÂÂÂÂÂ add->dma_bus_addr = args.dev_bus_addr;
> > +ÂÂÂ } else
> > +#endif
> > ÂÂÂÂÂ if (gnttab_alloc_pages(count, add->pages))
> > ÂÂÂÂÂÂÂÂÂ goto err;
> > Â @@ -325,6 +401,14 @@ static int map_grant_pages(struct grant_map *map)
> > ÂÂÂÂÂÂÂÂÂ map->unmap_ops[i].handle = map->map_ops[i].handle;
> > ÂÂÂÂÂÂÂÂÂ if (use_ptemod)
> > ÂÂÂÂÂÂÂÂÂÂÂÂÂ map->kunmap_ops[i].handle = map->kmap_ops[i].handle;
> > +#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
> > +ÂÂÂÂÂÂÂ else if (map->dma_vaddr) {
> > +ÂÂÂÂÂÂÂÂÂÂÂ unsigned long mfn;
>
>
> This should be called bfn now.
Of course
> > +
> > +ÂÂÂÂÂÂÂÂÂÂÂ mfn = pfn_to_bfn(page_to_pfn(map->pages[i]));
> > +ÂÂÂÂÂÂÂÂÂÂÂ map->unmap_ops[i].dev_bus_addr = __pfn_to_phys(mfn);
> > +ÂÂÂÂÂÂÂ }
> > +#endif
> > ÂÂÂÂÂ }
> > ÂÂÂÂÂ return err;
> > Â }
> > @@ -548,6 +632,17 @@ static int gntdev_open(struct inode *inode, 
> > struct file *flip)
> > ÂÂÂÂÂ }
> > Â ÂÂÂÂÂ flip->private_data = priv;
> > +#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
> > +ÂÂÂ priv->dma_dev = gntdev_miscdev.this_device;
> > +
> > +ÂÂÂ /*
> > +ÂÂÂÂ * The device is not spawn from a device tree, so 
> > arch_setup_dma_ops
> > +ÂÂÂÂ * is not called, thus leaving the device with dummy DMA ops.
> > +ÂÂÂÂ * Fix this call of_dma_configure() with a NULL node to set
>
>
> "Fix this by calling ..." I think.
Will fix
> > +ÂÂÂÂ * default DMA ops.
> > +ÂÂÂÂ */
> > +ÂÂÂ of_dma_configure(priv->dma_dev, NULL);
> > +#endif
> > ÂÂÂÂÂ pr_debug("priv %p\n", priv);
> > Â ÂÂÂÂÂ return 0;
>
>
> With those fixed,
>
> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>
Thank you,
Oleksandr