Hi David, I love your patch! Perhaps something to improve: [auto build test WARNING on next-20220106] [cannot apply to cifs/for-next linus/master v5.16-rc8 v5.16-rc7 v5.16-rc6 v5.16-rc8] [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/David-Howells/cifs-In-progress-conversion-to-use-iov_iters-instead-of-page-lists/20220107-053700 base: 3770333b3f8cb7c9110889853afaa49777c26ea7 config: i386-randconfig-r026-20220107 (https://download.01.org/0day-ci/archive/20220107/202201072209.NObYCbNl-lkp@intel.com/config) compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 32167bfe64a4c5dd4eb3f7a58e24f4cba76f5ac2) 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 # https://github.com/0day-ci/linux/commit/f6d9da3b96ace245edc0dcdb78607b58edef4dcb git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review David-Howells/cifs-In-progress-conversion-to-use-iov_iters-instead-of-page-lists/20220107-053700 git checkout f6d9da3b96ace245edc0dcdb78607b58edef4dcb # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/gpu/drm/amd/amdgpu/ drivers/gpu/drm/i810/ drivers/i2c/busses/ drivers/pci/endpoint/functions/ fs/cifs/ sound/pci/ If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot All warnings (new ones prefixed by >>): >> fs/cifs/smb2ops.c:4902:7: warning: variable 'length' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized] if (rdata->result != 0) { ^~~~~~~~~~~~~~~~~~ fs/cifs/smb2ops.c:4931:9: note: uninitialized use occurs here return length; ^~~~~~ fs/cifs/smb2ops.c:4902:3: note: remove the 'if' if its condition is always true if (rdata->result != 0) { ^~~~~~~~~~~~~~~~~~~~~~~~ fs/cifs/smb2ops.c:4801:12: note: initialize the variable 'length' to silence this warning int length; ^ = 0 1 warning generated. vim +4902 fs/cifs/smb2ops.c c42a6abe3012832 Pavel Shilovsky 2016-11-17 4787 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4788 static int 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4789 handle_read_data(struct TCP_Server_Info *server, struct mid_q_entry *mid, 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4790 char *buf, unsigned int buf_len, struct page **pages, de9ac0a6e9efdff Rohith Surabattula 2020-10-28 4791 unsigned int npages, unsigned int page_data_size, de9ac0a6e9efdff Rohith Surabattula 2020-10-28 4792 bool is_offloaded) 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4793 { 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4794 unsigned int data_offset; 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4795 unsigned int data_len; c42a6abe3012832 Pavel Shilovsky 2016-11-17 4796 unsigned int cur_off; c42a6abe3012832 Pavel Shilovsky 2016-11-17 4797 unsigned int cur_page_idx; c42a6abe3012832 Pavel Shilovsky 2016-11-17 4798 unsigned int pad_len; 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4799 struct cifs_readdata *rdata = mid->callback_data; 0d35e382e4e96a4 Ronnie Sahlberg 2021-11-05 4800 struct smb2_hdr *shdr = (struct smb2_hdr *)buf; 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4801 int length; 74dcf418fe34465 Long Li 2017-11-22 4802 bool use_rdma_mr = false; 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4803 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4804 if (shdr->Command != SMB2_READ) { 3175eb9b577e82b Ronnie Sahlberg 2019-09-04 4805 cifs_server_dbg(VFS, "only big read responses are supported\n"); 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4806 return -ENOTSUPP; 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4807 } 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4808 511c54a2f69195b Pavel Shilovsky 2017-07-08 4809 if (server->ops->is_session_expired && 511c54a2f69195b Pavel Shilovsky 2017-07-08 4810 server->ops->is_session_expired(buf)) { de9ac0a6e9efdff Rohith Surabattula 2020-10-28 4811 if (!is_offloaded) 183eea2ee5ba968 Shyam Prasad N 2021-07-19 4812 cifs_reconnect(server, true); 511c54a2f69195b Pavel Shilovsky 2017-07-08 4813 return -1; 511c54a2f69195b Pavel Shilovsky 2017-07-08 4814 } 511c54a2f69195b Pavel Shilovsky 2017-07-08 4815 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4816 if (server->ops->is_status_pending && 66265f134acfb20 Pavel Shilovsky 2019-01-23 4817 server->ops->is_status_pending(buf, server)) 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4818 return -1; 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4819 ec678eae746dd25 Pavel Shilovsky 2019-01-18 4820 /* set up first two iov to get credits */ ec678eae746dd25 Pavel Shilovsky 2019-01-18 4821 rdata->iov[0].iov_base = buf; bb1bccb60c2ebd9 Pavel Shilovsky 2019-01-17 4822 rdata->iov[0].iov_len = 0; bb1bccb60c2ebd9 Pavel Shilovsky 2019-01-17 4823 rdata->iov[1].iov_base = buf; ec678eae746dd25 Pavel Shilovsky 2019-01-18 4824 rdata->iov[1].iov_len = bb1bccb60c2ebd9 Pavel Shilovsky 2019-01-17 4825 min_t(unsigned int, buf_len, server->vals->read_rsp_size); ec678eae746dd25 Pavel Shilovsky 2019-01-18 4826 cifs_dbg(FYI, "0: iov_base=%p iov_len=%zu\n", ec678eae746dd25 Pavel Shilovsky 2019-01-18 4827 rdata->iov[0].iov_base, rdata->iov[0].iov_len); ec678eae746dd25 Pavel Shilovsky 2019-01-18 4828 cifs_dbg(FYI, "1: iov_base=%p iov_len=%zu\n", ec678eae746dd25 Pavel Shilovsky 2019-01-18 4829 rdata->iov[1].iov_base, rdata->iov[1].iov_len); ec678eae746dd25 Pavel Shilovsky 2019-01-18 4830 ec678eae746dd25 Pavel Shilovsky 2019-01-18 4831 rdata->result = server->ops->map_error(buf, true); 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4832 if (rdata->result != 0) { 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4833 cifs_dbg(FYI, "%s: server returned error %d\n", 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4834 __func__, rdata->result); ec678eae746dd25 Pavel Shilovsky 2019-01-18 4835 /* normal error on read response */ ac873aa3dc21707 Rohith Surabattula 2020-10-29 4836 if (is_offloaded) ac873aa3dc21707 Rohith Surabattula 2020-10-29 4837 mid->mid_state = MID_RESPONSE_RECEIVED; ac873aa3dc21707 Rohith Surabattula 2020-10-29 4838 else ec678eae746dd25 Pavel Shilovsky 2019-01-18 4839 dequeue_mid(mid, false); 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4840 return 0; 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4841 } 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4842 1fc6ad2f10ad6f5 Ronnie Sahlberg 2018-06-01 4843 data_offset = server->ops->read_data_offset(buf); 74dcf418fe34465 Long Li 2017-11-22 4844 #ifdef CONFIG_CIFS_SMB_DIRECT 74dcf418fe34465 Long Li 2017-11-22 4845 use_rdma_mr = rdata->mr; 74dcf418fe34465 Long Li 2017-11-22 4846 #endif 74dcf418fe34465 Long Li 2017-11-22 4847 data_len = server->ops->read_data_length(buf, use_rdma_mr); 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4848 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4849 if (data_offset < server->vals->read_rsp_size) { 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4850 /* 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4851 * win2k8 sometimes sends an offset of 0 when the read 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4852 * is beyond the EOF. Treat it as if the data starts just after 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4853 * the header. 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4854 */ 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4855 cifs_dbg(FYI, "%s: data offset (%u) inside read response header\n", 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4856 __func__, data_offset); 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4857 data_offset = server->vals->read_rsp_size; 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4858 } else if (data_offset > MAX_CIFS_SMALL_BUFFER_SIZE) { 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4859 /* data_offset is beyond the end of smallbuf */ 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4860 cifs_dbg(FYI, "%s: data offset (%u) beyond end of smallbuf\n", 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4861 __func__, data_offset); 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4862 rdata->result = -EIO; ac873aa3dc21707 Rohith Surabattula 2020-10-29 4863 if (is_offloaded) ac873aa3dc21707 Rohith Surabattula 2020-10-29 4864 mid->mid_state = MID_RESPONSE_MALFORMED; ac873aa3dc21707 Rohith Surabattula 2020-10-29 4865 else 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4866 dequeue_mid(mid, rdata->result); 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4867 return 0; 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4868 } 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4869 c42a6abe3012832 Pavel Shilovsky 2016-11-17 4870 pad_len = data_offset - server->vals->read_rsp_size; c42a6abe3012832 Pavel Shilovsky 2016-11-17 4871 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4872 if (buf_len <= data_offset) { 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4873 /* read response payload is in pages */ c42a6abe3012832 Pavel Shilovsky 2016-11-17 4874 cur_page_idx = pad_len / PAGE_SIZE; c42a6abe3012832 Pavel Shilovsky 2016-11-17 4875 cur_off = pad_len % PAGE_SIZE; c42a6abe3012832 Pavel Shilovsky 2016-11-17 4876 c42a6abe3012832 Pavel Shilovsky 2016-11-17 4877 if (cur_page_idx != 0) { c42a6abe3012832 Pavel Shilovsky 2016-11-17 4878 /* data offset is beyond the 1st page of response */ c42a6abe3012832 Pavel Shilovsky 2016-11-17 4879 cifs_dbg(FYI, "%s: data offset (%u) beyond 1st page of response\n", c42a6abe3012832 Pavel Shilovsky 2016-11-17 4880 __func__, data_offset); c42a6abe3012832 Pavel Shilovsky 2016-11-17 4881 rdata->result = -EIO; ac873aa3dc21707 Rohith Surabattula 2020-10-29 4882 if (is_offloaded) ac873aa3dc21707 Rohith Surabattula 2020-10-29 4883 mid->mid_state = MID_RESPONSE_MALFORMED; ac873aa3dc21707 Rohith Surabattula 2020-10-29 4884 else c42a6abe3012832 Pavel Shilovsky 2016-11-17 4885 dequeue_mid(mid, rdata->result); c42a6abe3012832 Pavel Shilovsky 2016-11-17 4886 return 0; c42a6abe3012832 Pavel Shilovsky 2016-11-17 4887 } c42a6abe3012832 Pavel Shilovsky 2016-11-17 4888 c42a6abe3012832 Pavel Shilovsky 2016-11-17 4889 if (data_len > page_data_size - pad_len) { c42a6abe3012832 Pavel Shilovsky 2016-11-17 4890 /* data_len is corrupt -- discard frame */ c42a6abe3012832 Pavel Shilovsky 2016-11-17 4891 rdata->result = -EIO; ac873aa3dc21707 Rohith Surabattula 2020-10-29 4892 if (is_offloaded) ac873aa3dc21707 Rohith Surabattula 2020-10-29 4893 mid->mid_state = MID_RESPONSE_MALFORMED; ac873aa3dc21707 Rohith Surabattula 2020-10-29 4894 else c42a6abe3012832 Pavel Shilovsky 2016-11-17 4895 dequeue_mid(mid, rdata->result); c42a6abe3012832 Pavel Shilovsky 2016-11-17 4896 return 0; c42a6abe3012832 Pavel Shilovsky 2016-11-17 4897 } c42a6abe3012832 Pavel Shilovsky 2016-11-17 4898 f6d9da3b96ace24 David Howells 2022-01-06 4899 /* Copy the data to the output I/O iterator. */ f6d9da3b96ace24 David Howells 2022-01-06 4900 rdata->result = cifs_copy_pages_to_iter(pages, npages, page_data_size, f6d9da3b96ace24 David Howells 2022-01-06 4901 cur_off, &rdata->iter); c42a6abe3012832 Pavel Shilovsky 2016-11-17 @4902 if (rdata->result != 0) { ac873aa3dc21707 Rohith Surabattula 2020-10-29 4903 if (is_offloaded) ac873aa3dc21707 Rohith Surabattula 2020-10-29 4904 mid->mid_state = MID_RESPONSE_MALFORMED; ac873aa3dc21707 Rohith Surabattula 2020-10-29 4905 else c42a6abe3012832 Pavel Shilovsky 2016-11-17 4906 dequeue_mid(mid, rdata->result); c42a6abe3012832 Pavel Shilovsky 2016-11-17 4907 return 0; c42a6abe3012832 Pavel Shilovsky 2016-11-17 4908 } c42a6abe3012832 Pavel Shilovsky 2016-11-17 4909 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4910 } else if (buf_len >= data_offset + data_len) { 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4911 /* read response payload is in buf */ 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4912 WARN_ONCE(npages > 0, "read data can be either in buf or in pages"); f6d9da3b96ace24 David Howells 2022-01-06 4913 length = copy_to_iter(buf + data_offset, data_len, &rdata->iter); f6d9da3b96ace24 David Howells 2022-01-06 4914 if (length < 0) f6d9da3b96ace24 David Howells 2022-01-06 4915 return length; 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4916 } else { 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4917 /* read response payload cannot be in both buf and pages */ 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4918 WARN_ONCE(1, "buf can not contain only a part of read data"); 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4919 rdata->result = -EIO; ac873aa3dc21707 Rohith Surabattula 2020-10-29 4920 if (is_offloaded) ac873aa3dc21707 Rohith Surabattula 2020-10-29 4921 mid->mid_state = MID_RESPONSE_MALFORMED; ac873aa3dc21707 Rohith Surabattula 2020-10-29 4922 else 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4923 dequeue_mid(mid, rdata->result); 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4924 return 0; 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4925 } 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4926 ac873aa3dc21707 Rohith Surabattula 2020-10-29 4927 if (is_offloaded) ac873aa3dc21707 Rohith Surabattula 2020-10-29 4928 mid->mid_state = MID_RESPONSE_RECEIVED; ac873aa3dc21707 Rohith Surabattula 2020-10-29 4929 else 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4930 dequeue_mid(mid, false); 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4931 return length; 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4932 } 4326ed2f6a16ae9 Pavel Shilovsky 2016-11-17 4933 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org