[ammarfaizi2-block:dhowells/linux-fs/netfs-lib 21/24] fs/netfs/read_helper.c:971:14: warning: variable 'folio' is uninitialized when used here

[ammarfaizi2-block:dhowells/linux-fs/netfs-lib 21/24] fs/netfs/read_helper.c:971:14: warning: variable 'folio' is uninitialized when used here

[kernel test robot]

tree:   https://github.com/ammarfaizi2/linux-block dhowells/linux-fs/netfs-lib
head:   e450b62f32df4384c141a6a382811b3fe5723bad
commit: 814cca7df840c441b1ac007bcb3eb8bfaeacb13f [21/24] cifs: Support fscache rewrite
config: arm-s3c2410_defconfig (https://download.01.org/0day-ci/archive/20220118/202201180713.iy4mum5Q-lkp@intel.com/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 5f782d25a742302d25ef3c8b84b54f7483c2deb9)
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
        # https://github.com/ammarfaizi2/linux-block/commit/814cca7df840c441b1ac007bcb3eb8bfaeacb13f
        git remote add ammarfaizi2-block https://github.com/ammarfaizi2/linux-block
        git fetch --no-tags ammarfaizi2-block dhowells/linux-fs/netfs-lib
        git checkout 814cca7df840c441b1ac007bcb3eb8bfaeacb13f
        # 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=arm SHELL=/bin/bash fs/netfs/

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 >>):

>> fs/netfs/read_helper.c:971:14: warning: variable 'folio' is uninitialized when used here [-Wuninitialized]
                           folio_put(folio);
                                     ^~~~~
   fs/netfs/read_helper.c:920:21: note: initialize the variable 'folio' to silence this warning
           struct folio *folio;
                              ^
                               = NULL
   fs/netfs/read_helper.c:1267:7: error: implicit declaration of function 'netfs_is_cache_enabled' [-Werror,-Wimplicit-function-declaration]
           if (!netfs_is_cache_enabled(ctx) &&
                ^
   1 warning and 1 error generated.


vim +/folio +971 fs/netfs/read_helper.c

e6b340ed3634bb David Howells 2021-07-09  935  
e6b340ed3634bb David Howells 2021-07-09  936  	ret = netfs_rreq_add_folios_to_buffer(rreq, want_index, have_index - 1,
e6b340ed3634bb David Howells 2021-07-09  937  					      gfp_mask);
e6b340ed3634bb David Howells 2021-07-09  938  	if (ret < 0)
e6b340ed3634bb David Howells 2021-07-09  939  		return ret;
e6b340ed3634bb David Howells 2021-07-09  940  	have_folios += have_index - want_index;
e6b340ed3634bb David Howells 2021-07-09  941  
e6b340ed3634bb David Howells 2021-07-09  942  	ret = netfs_rreq_add_folios_to_buffer(rreq, have_index + have_folios,
e6b340ed3634bb David Howells 2021-07-09  943  					      want_index + want_folios - 1,
e6b340ed3634bb David Howells 2021-07-09  944  					      gfp_mask);
e6b340ed3634bb David Howells 2021-07-09  945  	if (ret < 0)
e6b340ed3634bb David Howells 2021-07-09  946  		return ret;
e6b340ed3634bb David Howells 2021-07-09  947  
e6b340ed3634bb David Howells 2021-07-09  948  	/* Transfer the folios proposed by the VM into the buffer and take refs
e6b340ed3634bb David Howells 2021-07-09  949  	 * on them.  The locks will be dropped in netfs_rreq_unlock().
e6b340ed3634bb David Howells 2021-07-09  950  	 */
e6b340ed3634bb David Howells 2021-07-09  951  	if (ractl) {
e6b340ed3634bb David Howells 2021-07-09  952  		while ((folio = readahead_folio(ractl))) {
e6b340ed3634bb David Howells 2021-07-09  953  			folio_get(folio);
e6b340ed3634bb David Howells 2021-07-09  954  			if (folio == keep)
e6b340ed3634bb David Howells 2021-07-09  955  				folio_get(folio);
e6b340ed3634bb David Howells 2021-07-09  956  			ret = xa_insert_set_mark(&rreq->buffer,
e6b340ed3634bb David Howells 2021-07-09  957  						 folio_index(folio), folio,
e6b340ed3634bb David Howells 2021-07-09  958  						 XA_MARK_0, gfp_mask);
e6b340ed3634bb David Howells 2021-07-09  959  			if (ret < 0) {
e6b340ed3634bb David Howells 2021-07-09  960  				if (folio != keep)
e6b340ed3634bb David Howells 2021-07-09  961  					folio_unlock(folio);
e6b340ed3634bb David Howells 2021-07-09  962  				folio_put(folio);
e6b340ed3634bb David Howells 2021-07-09  963  				return ret;
e6b340ed3634bb David Howells 2021-07-09  964  			}
e6b340ed3634bb David Howells 2021-07-09  965  		}
e6b340ed3634bb David Howells 2021-07-09  966  	} else {
e6b340ed3634bb David Howells 2021-07-09  967  		folio_get(keep);
e6b340ed3634bb David Howells 2021-07-09  968  		ret = xa_insert_set_mark(&rreq->buffer, keep->index, keep,
e6b340ed3634bb David Howells 2021-07-09  969  					 XA_MARK_0, gfp_mask);
e6b340ed3634bb David Howells 2021-07-09  970  		if (ret < 0) {
e6b340ed3634bb David Howells 2021-07-09 @971  			folio_put(folio);
e6b340ed3634bb David Howells 2021-07-09  972  			return ret;
e6b340ed3634bb David Howells 2021-07-09  973  		}
e6b340ed3634bb David Howells 2021-07-09  974  	}
e6b340ed3634bb David Howells 2021-07-09  975  	return 0;
e6b340ed3634bb David Howells 2021-07-09  976  }
e6b340ed3634bb David Howells 2021-07-09  977  

:::::: The code at line 971 was first introduced by commit
:::::: e6b340ed3634bb80396afb564c499eebdeff601f netfs: Use a buffer in netfs_read_request and add pages to it

:::::: TO: David Howells <dhowells@redhat.com>
:::::: CC: David Howells <dhowells@redhat.com>

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