Date:   Sat, 18 Dec 2021 12:03:07 +0800
From:   kernel test robot <lkp@intel.com>
To:     Tianyu Lan <Tianyu.Lan@microsoft.com>
Cc:     kbuild-all@lists.01.org, linux-kernel@vger.kernel.org,
        Wei Liu <wei.liu@kernel.org>,
        Michael Kelley <mikelley@microsoft.com>
Subject: [hyperv:hyperv-next 1/5] kernel/dma/swiotlb.c:166:7: warning: no
 previous prototype for 'swiotlb_mem_remap'
Message-ID: <202112181114.Vxt6EAJR-lkp@intel.com>
MIME-Version: 1.0
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tree:   https://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git hyperv-next
head:   19fd7ca00201c0525452dcf5a490e4b01674ef4c
commit: 32be866293fe5355adbf91da1cd612f439fc71e5 [1/5] swiotlb: Add swiotlb bounce buffer remap function for HV IVM
config: x86_64-randconfig-r001-20211216 (https://download.01.org/0day-ci/archive/20211218/202112181114.Vxt6EAJR-lkp@intel.com/config)
compiler: gcc-9 (Debian 9.3.0-22) 9.3.0
reproduce (this is a W=1 build):
        # https://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git/commit/?id=32be866293fe5355adbf91da1cd612f439fc71e5
        git remote add hyperv https://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux.git
        git fetch --no-tags hyperv hyperv-next
        git checkout 32be866293fe5355adbf91da1cd612f439fc71e5
        # save the config file to linux build tree
        mkdir build_dir
        make W=1 O=build_dir ARCH=x86_64 SHELL=/bin/bash kernel/dma/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All warnings (new ones prefixed by >>):

>> kernel/dma/swiotlb.c:166:7: warning: no previous prototype for 'swiotlb_mem_remap' [-Wmissing-prototypes]
     166 | void *swiotlb_mem_remap(struct io_tlb_mem *mem, unsigned long bytes)
         |       ^~~~~~~~~~~~~~~~~


vim +/swiotlb_mem_remap +166 kernel/dma/swiotlb.c

   160	
   161	/*
   162	 * Remap swioltb memory in the unencrypted physical address space
   163	 * when swiotlb_unencrypted_base is set. (e.g. for Hyper-V AMD SEV-SNP
   164	 * Isolation VMs).
   165	 */
 > 166	void *swiotlb_mem_remap(struct io_tlb_mem *mem, unsigned long bytes)
   167	{
   168		void *vaddr = NULL;
   169	
   170		if (swiotlb_unencrypted_base) {
   171			phys_addr_t paddr = mem->start + swiotlb_unencrypted_base;
   172	
   173			vaddr = memremap(paddr, bytes, MEMREMAP_WB);
   174			if (!vaddr)
   175				pr_err("Failed to map the unencrypted memory %llx size %lx.\n",
   176				       paddr, bytes);
   177		}
   178	
   179		return vaddr;
   180	}
   181	

---
0-DAY CI Kernel Test Service, Intel Corporation
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