Re: [PATCH vhost v12 10/10] virtio_net: merge dma operations when filling mergeable buffers
From: kernel test robot <hidden>
Date: 2023-07-19 10:33:57
Also in:
bpf, oe-kbuild-all, virtualization
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@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@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 [off-list ref] | Closes: https://lore.kernel.org/oe-kbuild-all/202307191819.0tatknWa-lkp@intel.com/ (local) All warnings (new ones prefixed by >>): drivers/net/virtio_net.c: In function 'virtnet_rq_init_one_sg':
quoted
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':quoted
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
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