[hch-misc:block-new-helpers 18/18] kernel/power/swap.c:381:6: warning: variable 'src' is used uninitialized whenever 'if' condition is true

[hch-misc:block-new-helpers 18/18] kernel/power/swap.c:381:6: warning: variable 'src' is used uninitialized whenever 'if' condition is true

[kernel test robot]

tree:   git://git.infradead.org/users/hch/misc.git block-new-helpers
head:   280d8b7173282de4cf4857624def142ed24fad63
commit: 280d8b7173282de4cf4857624def142ed24fad63 [18/18] PM: hibernate: split and simplify hib_submit_io
config: i386-buildonly-randconfig-001-20250422 (https://download.01.org/0day-ci/archive/20250422/202504220332.MiiqLjIT-lkp@intel.com/config)
compiler: clang version 20.1.2 (https://github.com/llvm/llvm-project 58df0ef89dd64126512e4ee27b4ac3fd8ddf6247)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250422/202504220332.MiiqLjIT-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/202504220332.MiiqLjIT-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> kernel/power/swap.c:381:6: warning: variable 'src' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
     381 |         if (!hb)
         |             ^~~
   kernel/power/swap.c:397:61: note: uninitialized use occurs here
     397 |         return hib_submit_io_sync(REQ_OP_WRITE | REQ_SYNC, offset, src);
         |                                                                    ^~~
   kernel/power/swap.c:381:2: note: remove the 'if' if its condition is always false
     381 |         if (!hb)
         |         ^~~~~~~~
     382 |                 goto sync_io;
         |                 ~~~~~~~~~~~~
   kernel/power/swap.c:375:11: note: initialize the variable 'src' to silence this warning
     375 |         void *src;
         |                  ^
         |                   = NULL
   1 warning generated.


vim +381 kernel/power/swap.c

   364	
   365	/**
   366	 *	write_page - Write one page to given swap location.
   367	 *	@buf:		Address we're writing.
   368	 *	@offset:	Offset of the swap page we're writing to.
   369	 *	@hb:		bio completion batch
   370	 */
   371	
   372	static int write_page(void *buf, sector_t offset, struct hib_bio_batch *hb)
   373	{
   374		gfp_t gfp = GFP_NOIO | __GFP_NOWARN | __GFP_NORETRY;
   375		void *src;
   376		int ret;
   377	
   378		if (!offset)
   379			return -ENOSPC;
   380	
 > 381		if (!hb)
   382			goto sync_io;
   383	
   384		src = (void *)__get_free_page(gfp);
   385		if (!src) {
   386			ret = hib_wait_io(hb); /* Free pages */
   387			if (ret)
   388				return ret;
   389			src = (void *)__get_free_page(gfp);
   390			if (WARN_ON_ONCE(!src))
   391				goto sync_io;
   392		}
   393	
   394		copy_page(src, buf);
   395		return hib_submit_io_async(REQ_OP_WRITE | REQ_SYNC, offset, src, hb);
   396	sync_io:
   397		return hib_submit_io_sync(REQ_OP_WRITE | REQ_SYNC, offset, src);
   398	}
   399	

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