thr3ads.net - Virtualization - [PATCH vhost v12 10/10] virtio_net: merge dma operations when filling mergeable buffers [Jul 2023]

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kernel test robot

2023-Jul-19 10:33 UTC

[PATCH vhost v12 10/10] virtio_net: merge dma operations when filling mergeable buffers

Hi Xuan,

kernel test robot noticed the following build warnings:

[auto build test WARNING on v6.4]
[cannot apply to mst-vhost/linux-next linus/master v6.5-rc2 v6.5-rc1
next-20230719]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:   
https://github.com/intel-lab-lkp/linux/commits/Xuan-Zhuo/virtio_ring-check-use_dma_api-before-unmap-desc-for-indirect/20230719-121424
base:   v6.4
patch link:   
https://lore.kernel.org/r/20230719040422.126357-11-xuanzhuo%40linux.alibaba.com
patch subject: [PATCH vhost v12 10/10] virtio_net: merge dma operations when
filling mergeable buffers
config: i386-randconfig-i006-20230718
(https://download.01.org/0day-ci/archive/20230719/202307191819.0tatknWa-lkp at
intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce:
(https://download.01.org/0day-ci/archive/20230719/202307191819.0tatknWa-lkp at
intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp at intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202307191819.0tatknWa-lkp at
intel.com/

All warnings (new ones prefixed by >>):

   drivers/net/virtio_net.c: In function
'virtnet_rq_init_one_sg':>> drivers/net/virtio_net.c:624:41: warning: cast from pointer to integer
of different size [-Wpointer-to-int-cast]     624 |                 rq->sg[0].dma_address = (dma_addr_t)addr;
         |                                         ^
   drivers/net/virtio_net.c: In function
'virtnet_rq_alloc':>> drivers/net/virtio_net.c:682:28: warning: cast to pointer from integer
of different size [-Wint-to-pointer-cast]     682 |                 *sg_addr = (void *)(dma->addr +
alloc_frag->offset - sizeof(*dma));
         |                            ^


vim +624 drivers/net/virtio_net.c

   619	
   620	static void virtnet_rq_init_one_sg(struct receive_queue *rq, void *addr,
u32 len)
   621	{
   622		if (rq->do_dma) {
   623			sg_init_table(rq->sg, 1);
 > 624			rq->sg[0].dma_address = (dma_addr_t)addr;
   625			rq->sg[0].length = len;
   626		} else {
   627			sg_init_one(rq->sg, addr, len);
   628		}
   629	}
   630	
   631	static void *virtnet_rq_alloc(struct receive_queue *rq, u32 size,
   632				      void **sg_addr, gfp_t gfp)
   633	{
   634		struct page_frag *alloc_frag = &rq->alloc_frag;
   635		struct virtnet_rq_dma *dma;
   636		struct device *dev;
   637		void *buf, *head;
   638		dma_addr_t addr;
   639	
   640		if (unlikely(!skb_page_frag_refill(size, alloc_frag, gfp)))
   641			return NULL;
   642	
   643		head = (char *)page_address(alloc_frag->page);
   644	
   645		if (rq->do_dma) {
   646			dma = head;
   647	
   648			/* new pages */
   649			if (!alloc_frag->offset) {
   650				if (rq->last_dma) {
   651					/* Now, the new page is allocated, the last dma
   652					 * will not be used. So the dma can be unmapped
   653					 * if the ref is 0.
   654					 */
   655					virtnet_rq_unmap(rq, rq->last_dma, 0);
   656					rq->last_dma = NULL;
   657				}
   658	
   659				dev = virtqueue_dma_dev(rq->vq);
   660	
   661				dma->len = alloc_frag->size - sizeof(*dma);
   662	
   663				addr = dma_map_single_attrs(dev, dma + 1, dma->len,
DMA_FROM_DEVICE, 0);
   664				if (addr == DMA_MAPPING_ERROR)
   665					return NULL;
   666	
   667				dma->addr = addr;
   668				dma->need_sync = dma_need_sync(dev, addr);
   669	
   670				/* Add a reference to dma to prevent the entire dma from
   671				 * being released during error handling. This reference
   672				 * will be freed after the pages are no longer used.
   673				 */
   674				get_page(alloc_frag->page);
   675				dma->ref = 1;
   676				alloc_frag->offset = sizeof(*dma);
   677	
   678				rq->last_dma = dma;
   679			}
   680	
   681			++dma->ref;
 > 682			*sg_addr = (void *)(dma->addr + alloc_frag->offset -
sizeof(*dma));
   683		} else {
   684			*sg_addr = head + alloc_frag->offset;
   685		}
   686	
   687		buf = head + alloc_frag->offset;
   688	
   689		get_page(alloc_frag->page);
   690		alloc_frag->offset += size;
   691	
   692		return buf;
   693	}
   694	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Michael S. Tsirkin

2023-Jul-19 11:05 UTC

head link

[PATCH vhost v12 10/10] virtio_net: merge dma operations when filling mergeable buffers

On Wed, Jul 19, 2023 at 06:33:05PM +0800, kernel test robot
wrote:> Hi Xuan,
> 
> kernel test robot noticed the following build warnings:
> 
> [auto build test WARNING on v6.4]
> [cannot apply to mst-vhost/linux-next linus/master v6.5-rc2 v6.5-rc1
next-20230719]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented
in
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
> 
> url:   
https://github.com/intel-lab-lkp/linux/commits/Xuan-Zhuo/virtio_ring-check-use_dma_api-before-unmap-desc-for-indirect/20230719-121424
> base:   v6.4
> patch link:   
https://lore.kernel.org/r/20230719040422.126357-11-xuanzhuo%40linux.alibaba.com
> patch subject: [PATCH vhost v12 10/10] virtio_net: merge dma operations
when filling mergeable buffers
> config: i386-randconfig-i006-20230718
(https://download.01.org/0day-ci/archive/20230719/202307191819.0tatknWa-lkp at
intel.com/config)
> compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
> reproduce:
(https://download.01.org/0day-ci/archive/20230719/202307191819.0tatknWa-lkp at
intel.com/reproduce)
> 
> If you fix the issue in a separate patch/commit (i.e. not just a new
version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp at intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202307191819.0tatknWa-lkp
at intel.com/
> 
> All warnings (new ones prefixed by >>):
> 
>    drivers/net/virtio_net.c: In function 'virtnet_rq_init_one_sg':
> >> drivers/net/virtio_net.c:624:41: warning: cast from pointer to
integer of different size [-Wpointer-to-int-cast]
>      624 |                 rq->sg[0].dma_address = (dma_addr_t)addr;
>          |                                         ^
>    drivers/net/virtio_net.c: In function 'virtnet_rq_alloc':
> >> drivers/net/virtio_net.c:682:28: warning: cast to pointer from
integer of different size [-Wint-to-pointer-cast]
>      682 |                 *sg_addr = (void *)(dma->addr +
alloc_frag->offset - sizeof(*dma));
>          |                            ^

yea these casts are pretty creepy. I think it's possible dma_addr_t
won't fit in a pointer
or a pointer won't fit in dma_addr_t.
> 
> vim +624 drivers/net/virtio_net.c
> 
>    619	
>    620	static void virtnet_rq_init_one_sg(struct receive_queue *rq, void
*addr, u32 len)
>    621	{
>    622		if (rq->do_dma) {
>    623			sg_init_table(rq->sg, 1);
>  > 624			rq->sg[0].dma_address = (dma_addr_t)addr;
>    625			rq->sg[0].length = len;
>    626		} else {
>    627			sg_init_one(rq->sg, addr, len);
>    628		}
>    629	}
>    630	
>    631	static void *virtnet_rq_alloc(struct receive_queue *rq, u32 size,
>    632				      void **sg_addr, gfp_t gfp)
>    633	{
>    634		struct page_frag *alloc_frag = &rq->alloc_frag;
>    635		struct virtnet_rq_dma *dma;
>    636		struct device *dev;
>    637		void *buf, *head;
>    638		dma_addr_t addr;
>    639	
>    640		if (unlikely(!skb_page_frag_refill(size, alloc_frag, gfp)))
>    641			return NULL;
>    642	
>    643		head = (char *)page_address(alloc_frag->page);
>    644	
>    645		if (rq->do_dma) {
>    646			dma = head;
>    647	
>    648			/* new pages */
>    649			if (!alloc_frag->offset) {
>    650				if (rq->last_dma) {
>    651					/* Now, the new page is allocated, the last dma
>    652					 * will not be used. So the dma can be unmapped
>    653					 * if the ref is 0.
>    654					 */
>    655					virtnet_rq_unmap(rq, rq->last_dma, 0);
>    656					rq->last_dma = NULL;
>    657				}
>    658	
>    659				dev = virtqueue_dma_dev(rq->vq);
>    660	
>    661				dma->len = alloc_frag->size - sizeof(*dma);
>    662	
>    663				addr = dma_map_single_attrs(dev, dma + 1, dma->len,
DMA_FROM_DEVICE, 0);
>    664				if (addr == DMA_MAPPING_ERROR)
>    665					return NULL;
>    666	
>    667				dma->addr = addr;
>    668				dma->need_sync = dma_need_sync(dev, addr);
>    669	
>    670				/* Add a reference to dma to prevent the entire dma from
>    671				 * being released during error handling. This reference
>    672				 * will be freed after the pages are no longer used.
>    673				 */
>    674				get_page(alloc_frag->page);
>    675				dma->ref = 1;
>    676				alloc_frag->offset = sizeof(*dma);
>    677	
>    678				rq->last_dma = dma;
>    679			}
>    680	
>    681			++dma->ref;
>  > 682			*sg_addr = (void *)(dma->addr + alloc_frag->offset -
sizeof(*dma));
>    683		} else {
>    684			*sg_addr = head + alloc_frag->offset;
>    685		}
>    686	
>    687		buf = head + alloc_frag->offset;
>    688	
>    689		get_page(alloc_frag->page);
>    690		alloc_frag->offset += size;
>    691	
>    692		return buf;
>    693	}
>    694	
> 
> -- 
> 0-DAY CI Kernel Test Service
> https://github.com/intel/lkp-tests/wiki

Virtualization - Jul 2023 - [PATCH vhost v12 10/10] virtio_net: merge dma operations when filling mergeable buffers

[PATCH vhost v12 10/10] virtio_net: merge dma operations when filling mergeable buffers

[PATCH vhost v12 10/10] virtio_net: merge dma operations when filling mergeable buffers