Hi Alessio, Thank you for the patch! Perhaps something to improve: [auto build test WARNING on v5.9-rc4] [cannot apply to fuse/for-next next-20200911] [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] url: https://github.com/0day-ci/linux/commits/Alessio-Balsini/fuse-Add-support... base: f4d51dffc6c01a9e94650d95ce0104964f8ae822 config: arm-randconfig-r025-20200911 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project 0448d11a06b451a63a8f60408fec613ad24801ba) reproduce (this is a W=1 build): wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # install arm cross compiling tool for clang build # apt-get install binutils-arm-linux-gnueabi # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=arm If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): int fuse_passthrough_open(struct fuse_dev *fud, ^ fs/fuse/dev.c:2222:1: note: declare 'static' if the function is not intended to be used outside of this translation unit int fuse_passthrough_open(struct fuse_dev *fud, ^ static 1 warning generated. # https://github.com/0day-ci/linux/commit/c8c14de554673fa450ce2cadee8957f5f... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Alessio-Balsini/fuse-Add-support-for-passthrough-read-write/20200912-003643 git checkout c8c14de554673fa450ce2cadee8957f5f8c021e3 vim +/fuse_passthrough_open +2222 fs/fuse/dev.c 2221 2223 struct fuse_passthrough_out *pto) 2224 { 2225 int ret; 2226 struct fuse_req *req; 2227 struct fuse_pqueue *fpq = &fud->pq; 2228 struct fuse_conn *fc = fud->fc; 2229 2230 if (!fc->passthrough) 2231 return -EPERM; 2232 2233 /* This field is reserved for future use */ 2234 if (pto->len != 0) 2235 return -EINVAL; 2236 2237 spin_lock(&fpq->lock); 2238 req = request_find(fpq, pto->unique & ~FUSE_INT_REQ_BIT); 2239 if (!req) { 2240 spin_unlock(&fpq->lock); 2241 return -ENOENT; 2242 } 2243 __fuse_get_request(req); 2244 spin_unlock(&fpq->lock); 2245 2246 ret = fuse_passthrough_setup(req, pto->fd); 2247 2248 __fuse_put_request(req); 2249 return ret; 2250 } 2251 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org