[amir73il:fuse-backing-fd 9/13] fs/fuse/passthrough.c:70:6: warning: variable 'fb' is used uninitialized whenever 'if' condition is false

[amir73il:fuse-backing-fd 9/13] fs/fuse/passthrough.c:70:6: warning: variable 'fb' is used uninitialized whenever 'if' condition is false

[kernel test robot]

tree:   https://github.com/amir73il/linux fuse-backing-fd
head:   d49ddc74f18aec5fb799e68b710df0f60928b2f5
commit: f89ded39822038bda45a92145fca90f6293767bb [9/13] fuse: implement ioctls to setup inode bound backing files
config: riscv-randconfig-r023-20230908 (https://download.01.org/0day-ci/archive/20230908/202309082011.xa56ORo3-lkp@intel.com/config)
compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.git 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20230908/202309082011.xa56ORo3-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202309082011.xa56ORo3-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> fs/fuse/passthrough.c:70:6: warning: variable 'fb' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
      70 |         if (inode) {
         |             ^~~~~
   fs/fuse/passthrough.c:81:9: note: uninitialized use occurs here
      81 |         return fb ?: ERR_PTR(err);
         |                ^~
   fs/fuse/passthrough.c:70:2: note: remove the 'if' if its condition is always true
      70 |         if (inode) {
         |         ^~~~~~~~~~~
   fs/fuse/passthrough.c:63:25: note: initialize the variable 'fb' to silence this warning
      63 |         struct fuse_backing *fb;
         |                                ^
         |                                 = NULL
   1 warning generated.


vim +70 fs/fuse/passthrough.c

    58	
    59	/* Detach the inode bound backing file from inode */
    60	static struct fuse_backing *fuse_backing_detach(struct fuse_conn *fc,
    61							u64 nodeid)
    62	{
    63		struct fuse_backing *fb;
    64		struct inode *inode;
    65		int err = -ENODEV;
    66	
    67		down_read(&fc->killsb);
    68	
    69		inode = fuse_ilookup(fc, nodeid, NULL);
  > 70		if (inode) {
    71			struct fuse_inode *fi = get_fuse_inode(inode);
    72	
    73			fb = xchg(&fi->fb, NULL);
    74			iput(inode);
    75			if (!fb)
    76				err = -ENOENT;
    77		}
    78	
    79		up_read(&fc->killsb);
    80	
    81		return fb ?: ERR_PTR(err);
    82	}
    83	

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