tree:   https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git netfs-folio
head:   3ce8c87a69a9d67778ec2b31543ded42147da837
commit: efccabcb40444cc288a5ce6817fbe2407d6ed961 [5/6] netfs, 9p, afs, ceph: Use folios
config: sparc-randconfig-r032-20211101 (attached as .config)
compiler: sparc64-linux-gcc (GCC) 11.2.0
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://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git/commit/?id=efccabcb40444cc288a5ce6817fbe2407d6ed961
        git remote add dhowells-fs https://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs.git
        git fetch --no-tags dhowells-fs netfs-folio
        git checkout efccabcb40444cc288a5ce6817fbe2407d6ed961
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross ARCH=sparc 

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

All errors (new ones prefixed by >>):

   fs/netfs/read_helper.c: In function 'netfs_rreq_unlock':
>> fs/netfs/read_helper.c:435:25: error: implicit declaration of function 'flush_dcache_folio'; did you mean 'flush_dcache_page'? [-Werror=implicit-function-declaration]
     435 |                         flush_dcache_folio(folio);
         |                         ^~~~~~~~~~~~~~~~~~
         |                         flush_dcache_page
   cc1: some warnings being treated as errors


vim +435 fs/netfs/read_helper.c

   368	
   369	/*
   370	 * Unlock the folios in a read operation.  We need to set PG_fscache on any
   371	 * folios we're going to write back before we unlock them.
   372	 */
   373	static void netfs_rreq_unlock(struct netfs_read_request *rreq)
   374	{
   375		struct netfs_read_subrequest *subreq;
   376		struct folio *folio;
   377		unsigned int iopos, account = 0;
   378		pgoff_t start_page = rreq->start / PAGE_SIZE;
   379		pgoff_t last_page = ((rreq->start + rreq->len) / PAGE_SIZE) - 1;
   380		bool subreq_failed = false;
   381	
   382		XA_STATE(xas, &rreq->mapping->i_pages, start_page);
   383	
   384		if (test_bit(NETFS_RREQ_FAILED, &rreq->flags)) {
   385			__clear_bit(NETFS_RREQ_WRITE_TO_CACHE, &rreq->flags);
   386			list_for_each_entry(subreq, &rreq->subrequests, rreq_link) {
   387				__clear_bit(NETFS_SREQ_WRITE_TO_CACHE, &subreq->flags);
   388			}
   389		}
   390	
   391		/* Walk through the pagecache and the I/O request lists simultaneously.
   392		 * We may have a mixture of cached and uncached sections and we only
   393		 * really want to write out the uncached sections.  This is slightly
   394		 * complicated by the possibility that we might have huge pages with a
   395		 * mixture inside.
   396		 */
   397		subreq = list_first_entry(&rreq->subrequests,
   398					  struct netfs_read_subrequest, rreq_link);
   399		iopos = 0;
   400		subreq_failed = (subreq->error < 0);
   401	
   402		trace_netfs_rreq(rreq, netfs_rreq_trace_unlock);
   403	
   404		rcu_read_lock();
   405		xas_for_each(&xas, folio, last_page) {
   406			unsigned int pgpos = (folio_index(folio) - start_page) * PAGE_SIZE;
   407			unsigned int pgend = pgpos + folio_size(folio);
   408			bool pg_failed = false;
   409	
   410			for (;;) {
   411				if (!subreq) {
   412					pg_failed = true;
   413					break;
   414				}
   415				if (test_bit(NETFS_SREQ_WRITE_TO_CACHE, &subreq->flags))
   416					folio_start_fscache(folio);
   417				pg_failed |= subreq_failed;
   418				if (pgend < iopos + subreq->len)
   419					break;
   420	
   421				account += subreq->transferred;
   422				iopos += subreq->len;
   423				if (!list_is_last(&subreq->rreq_link, &rreq->subrequests)) {
   424					subreq = list_next_entry(subreq, rreq_link);
   425					subreq_failed = (subreq->error < 0);
   426				} else {
   427					subreq = NULL;
   428					subreq_failed = false;
   429				}
   430				if (pgend == iopos)
   431					break;
   432			}
   433	
   434			if (!pg_failed) {
 > 435				flush_dcache_folio(folio);
   436				folio_mark_uptodate(folio);
   437			}
   438	
   439			if (!test_bit(NETFS_RREQ_DONT_UNLOCK_FOLIOS, &rreq->flags)) {
   440				if (folio_index(folio) == rreq->no_unlock_folio &&
   441				    test_bit(NETFS_RREQ_NO_UNLOCK_FOLIO, &rreq->flags))
   442					_debug("no unlock");
   443				else
   444					folio_unlock(folio);
   445			}
   446		}
   447		rcu_read_unlock();
   448	
   449		task_io_account_read(account);
   450		if (rreq->netfs_ops->done)
   451			rreq->netfs_ops->done(rreq);
   452	}
   453	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org