linux-kernel - Re: [PATCH 5/6] dma-mapping: Allow batched DMA sync operations if supported by the arch

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Message-ID: <202512211320.LaiSSLAc-lkp@intel.com>
Date: Sun, 21 Dec 2025 13:36:16 +0100
From: kernel test robot <lkp@...el.com>
To: Barry Song <21cnbao@...il.com>, catalin.marinas@....com,
	m.szyprowski@...sung.com, robin.murphy@....com, will@...nel.org
Cc: oe-kbuild-all@...ts.linux.dev, ada.coupriediaz@....com,
	anshuman.khandual@....com, ardb@...nel.org, iommu@...ts.linux.dev,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	maz@...nel.org, ryan.roberts@....com, surenb@...gle.com,
	v-songbaohua@...o.com, zhengtangquan@...o.com
Subject: Re: [PATCH 5/6] dma-mapping: Allow batched DMA sync operations if
 supported by the arch

Hi Barry,

kernel test robot noticed the following build errors:

[auto build test ERROR on linus/master]
[also build test ERROR on v6.19-rc1 next-20251219]
[cannot apply to arm64/for-next/core]
[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/Barry-Song/arm64-Provide-dcache_by_myline_op_nosync-helper/20251219-195810
base:   linus/master
patch link:    https://lore.kernel.org/r/20251219053658.84978-6-21cnbao%40gmail.com
patch subject: [PATCH 5/6] dma-mapping: Allow batched DMA sync operations if supported by the arch
config: x86_64-rhel-9.4 (https://download.01.org/0day-ci/archive/20251221/202512211320.LaiSSLAc-lkp@intel.com/config)
compiler: gcc-14 (Debian 14.2.0-19) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251221/202512211320.LaiSSLAc-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 <lkp@...el.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202512211320.LaiSSLAc-lkp@intel.com/

All errors (new ones prefixed by >>):

   kernel/dma/direct.c: In function 'dma_direct_unmap_sg':
>> kernel/dma/direct.c:456:25: error: implicit declaration of function 'dma_direct_unmap_phys_batch_add'; did you mean 'dma_direct_unmap_phys'? [-Wimplicit-function-declaration]
     456 |                         dma_direct_unmap_phys_batch_add(dev, sg->dma_address,
         |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
         |                         dma_direct_unmap_phys
   kernel/dma/direct.c: In function 'dma_direct_map_sg':
>> kernel/dma/direct.c:484:43: error: implicit declaration of function 'dma_direct_map_phys_batch_add'; did you mean 'dma_direct_map_phys'? [-Wimplicit-function-declaration]
     484 |                         sg->dma_address = dma_direct_map_phys_batch_add(dev, sg_phys(sg),
         |                                           ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
         |                                           dma_direct_map_phys


vim +456 kernel/dma/direct.c

   439	
   440	/*
   441	 * Unmaps segments, except for ones marked as pci_p2pdma which do not
   442	 * require any further action as they contain a bus address.
   443	 */
   444	void dma_direct_unmap_sg(struct device *dev, struct scatterlist *sgl,
   445			int nents, enum dma_data_direction dir, unsigned long attrs)
   446	{
   447		struct scatterlist *sg;
   448		int i;
   449		bool need_sync = false;
   450	
   451		for_each_sg(sgl,  sg, nents, i) {
   452			if (sg_dma_is_bus_address(sg)) {
   453				sg_dma_unmark_bus_address(sg);
   454			} else {
   455				need_sync = true;
 > 456				dma_direct_unmap_phys_batch_add(dev, sg->dma_address,
   457						      sg_dma_len(sg), dir, attrs);
   458			}
   459		}
   460		if (need_sync && !dev_is_dma_coherent(dev))
   461			arch_sync_dma_batch_flush();
   462	}
   463	#endif
   464	
   465	int dma_direct_map_sg(struct device *dev, struct scatterlist *sgl, int nents,
   466			enum dma_data_direction dir, unsigned long attrs)
   467	{
   468		struct pci_p2pdma_map_state p2pdma_state = {};
   469		struct scatterlist *sg;
   470		int i, ret;
   471		bool need_sync = false;
   472	
   473		for_each_sg(sgl, sg, nents, i) {
   474			switch (pci_p2pdma_state(&p2pdma_state, dev, sg_page(sg))) {
   475			case PCI_P2PDMA_MAP_THRU_HOST_BRIDGE:
   476				/*
   477				 * Any P2P mapping that traverses the PCI host bridge
   478				 * must be mapped with CPU physical address and not PCI
   479				 * bus addresses.
   480				 */
   481				break;
   482			case PCI_P2PDMA_MAP_NONE:
   483				need_sync = true;
 > 484				sg->dma_address = dma_direct_map_phys_batch_add(dev, sg_phys(sg),
   485						sg->length, dir, attrs);
   486				if (sg->dma_address == DMA_MAPPING_ERROR) {
   487					ret = -EIO;
   488					goto out_unmap;
   489				}
   490				break;
   491			case PCI_P2PDMA_MAP_BUS_ADDR:
   492				sg->dma_address = pci_p2pdma_bus_addr_map(
   493					p2pdma_state.mem, sg_phys(sg));
   494				sg_dma_len(sg) = sg->length;
   495				sg_dma_mark_bus_address(sg);
   496				continue;
   497			default:
   498				ret = -EREMOTEIO;
   499				goto out_unmap;
   500			}
   501			sg_dma_len(sg) = sg->length;
   502		}
   503	
   504		if (need_sync && !dev_is_dma_coherent(dev))
   505			arch_sync_dma_batch_flush();
   506		return nents;
   507	
   508	out_unmap:
   509		dma_direct_unmap_sg(dev, sgl, i, dir, attrs | DMA_ATTR_SKIP_CPU_SYNC);
   510		return ret;
   511	}
   512	

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