On 06/06/2018 04:14 AM, Oleksandr Andrushchenko wrote:
> On 06/04/2018 11:12 PM, Boris Ostrovsky wrote:
>> On 06/01/2018 07:41 AM, Oleksandr Andrushchenko wrote:
>> @@ -121,8 +146,27 @@ static void gntdev_free_map(struct grant_map *map)
>> if (map == NULL)
>> return;
>> +#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
>> + if (map->dma_vaddr) {
>> + struct gnttab_dma_alloc_args args;
>> +
>> + args.dev = map->dma_dev;
>> + args.coherent = map->dma_flags & GNTDEV_DMA_FLAG_COHERENT;
>> + args.nr_pages = map->count;
>> + args.pages = map->pages;
>> + args.frames = map->frames;
>> + args.vaddr = map->dma_vaddr;
>> + args.dev_bus_addr = map->dma_bus_addr;
>> +
>> + gnttab_dma_free_pages(&args);
>> + } else
>> +#endif
>> if (map->pages)
>> gnttab_free_pages(map->count, map->pages);
>> +
>> +#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
>> + kfree(map->frames);
>> +#endif
>>
>> Can this be done under if (map->dma_vaddr) ?
>
>> In other words, is it
>> possible for dma_vaddr to be NULL and still have unallocated frames
>> pointer?
> It is possible to have vaddr == NULL and frames != NULL as we
> allocate frames outside of gnttab_dma_alloc_pages which
> may fail. Calling kfree on NULL pointer is safe,
I am not questioning safety of the code, I would like avoid another ifdef.
> so
> I see no reason to change this code.
>>
>>> kfree(map->pages);
>>> kfree(map->grants);
>>> kfree(map->map_ops);
>>> @@ -132,7 +176,8 @@ static void gntdev_free_map(struct grant_map *map)
>>> kfree(map);
>>> }
>>> -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,
>>> + int dma_flags)
>>> {
>>> struct grant_map *add;
>>> int i;
>>> @@ -155,6 +200,37 @@ static struct grant_map
>>> *gntdev_alloc_map(struct gntdev_priv *priv, int count)
>>> NULL == add->pages)
>>> goto err;
>>> +#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
>>> + add->dma_flags = dma_flags;
>>> +
>>> + /*
>>> + * Check if this mapping is requested to be backed
>>> + * by a DMA buffer.
>>> + */
>>> + if (dma_flags & (GNTDEV_DMA_FLAG_WC | GNTDEV_DMA_FLAG_COHERENT)) {
>>> + struct gnttab_dma_alloc_args args;
>>> +
>>> + add->frames = kcalloc(count, sizeof(add->frames[0]),
>>> + GFP_KERNEL);
>>> + if (!add->frames)
>>> + goto err;
>>> +
>>> + /* Remember the device, so we can free DMA memory. */
>>> + add->dma_dev = priv->dma_dev;
>>> +
>>> + args.dev = priv->dma_dev;
>>> + args.coherent = dma_flags & GNTDEV_DMA_FLAG_COHERENT;
>>> + args.nr_pages = count;
>>> + args.pages = add->pages;
>>> + args.frames = add->frames;
>>> +
>>> + if (gnttab_dma_alloc_pages(&args))
>>> + goto err;
>>> +
>>> + add->dma_vaddr = args.vaddr;
>>> + add->dma_bus_addr = args.dev_bus_addr;
>>> + } else
>>> +#endif
>>> if (gnttab_alloc_pages(count, add->pages))
>>> goto err;
>>> @@ -325,6 +401,14 @@ static int map_grant_pages(struct grant_map
>>> *map)
>>> map->unmap_ops[i].handle = map->map_ops[i].handle;
>>> if (use_ptemod)
>>> map->kunmap_ops[i].handle = map->kmap_ops[i].handle;
>>> +#ifdef CONFIG_XEN_GRANT_DMA_ALLOC
>>> + else if (map->dma_vaddr) {
>>> + unsigned long mfn;
>>> +
>>> + mfn = __pfn_to_mfn(page_to_pfn(map->pages[i]));
>>
>> Not pfn_to_mfn()?
> I'd love to, but pfn_to_mfn is only defined for x86, not ARM: [1] and [2]
> Thus,
>
> drivers/xen/gntdev.c:408:10: error: implicit declaration of function
> ‘pfn_to_mfn’ [-Werror=implicit-function-declaration]
> mfn = pfn_to_mfn(page_to_pfn(map->pages[i]));
>
> So, I'll keep __pfn_to_mfn
How will this work on non-PV x86?
-boris
