Re: [PATCH v2 19/25] fuse: add io-uring kernel-managed buffer ring

[kernel test robot <lkp@intel.com>]

Hi Joanne,

kernel test robot noticed the following build warnings:

[auto build test WARNING on axboe/for-next]
[also build test WARNING on linus/master v6.19-rc1 next-20251219]
[cannot apply to mszeredi-fuse/for-next]
[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#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Joanne-Koong/io_uring-kbuf-refactor-io_buf_pbuf_register-logic-into-generic-helpers/20251218-165107
base:   https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux.git for-next
patch link:    https://lore.kernel.org/r/20251218083319.3485503-20-joannelkoong%40gmail.com
patch subject: [PATCH v2 19/25] fuse: add io-uring kernel-managed buffer ring
config: i386-allnoconfig-bpf (https://download.01.org/0day-ci/archive/20251220/202512202342.AGVIgnBx-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251220/202512202342.AGVIgnBx-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/202512202342.AGVIgnBx-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> fs/fuse/dev_uring.c:704:35: warning: format specifies type 'unsigned long' but the argument has type 'size_t' (aka 'unsigned int') [-Wformat]
     703 |                                     "header_type=%u, header_size=%lu, "
         |                                                                  ~~~
         |                                                                  %zu
     704 |                                     "use_bufring=%d\n", type, header_size,
         |                                                               ^~~~~~~~~~~
   ./include/linux/printk.h:726:46: note: expanded from macro 'pr_info_ratelimited'
     726 |         printk_ratelimited(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
         |                                             ~~~     ^~~~~~~~~~~
   ./include/linux/printk.h:706:17: note: expanded from macro 'printk_ratelimited'
     706 |                 printk(fmt, ##__VA_ARGS__);                             \
         |                        ~~~    ^~~~~~~~~~~
   ./include/linux/printk.h:512:60: note: expanded from macro 'printk'
     512 | #define printk(fmt, ...) printk_index_wrap(_printk, fmt, ##__VA_ARGS__)
         |                                                     ~~~    ^~~~~~~~~~~
   ./include/linux/printk.h:484:19: note: expanded from macro 'printk_index_wrap'
     484 |                 _p_func(_fmt, ##__VA_ARGS__);                           \
         |                         ~~~~    ^~~~~~~~~~~
   fs/fuse/dev_uring.c:743:35: warning: format specifies type 'unsigned long' but the argument has type 'size_t' (aka 'unsigned int') [-Wformat]
     742 |                                     "header_type=%u, header_size=%lu, "
         |                                                                  ~~~
         |                                                                  %zu
     743 |                                     "use_bufring=%d\n", type, header_size,
         |                                                               ^~~~~~~~~~~
   ./include/linux/printk.h:726:46: note: expanded from macro 'pr_info_ratelimited'
     726 |         printk_ratelimited(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
         |                                             ~~~     ^~~~~~~~~~~
   ./include/linux/printk.h:706:17: note: expanded from macro 'printk_ratelimited'
     706 |                 printk(fmt, ##__VA_ARGS__);                             \
         |                        ~~~    ^~~~~~~~~~~
   ./include/linux/printk.h:512:60: note: expanded from macro 'printk'
     512 | #define printk(fmt, ...) printk_index_wrap(_printk, fmt, ##__VA_ARGS__)
         |                                                     ~~~    ^~~~~~~~~~~
   ./include/linux/printk.h:484:19: note: expanded from macro 'printk_index_wrap'
     484 |                 _p_func(_fmt, ##__VA_ARGS__);                           \
         |                         ~~~~    ^~~~~~~~~~~
   2 warnings generated.


vim +704 fs/fuse/dev_uring.c

   670	
   671	static __always_inline int copy_header_to_ring(struct fuse_ring_ent *ent,
   672						       enum fuse_uring_header_type type,
   673						       const void *header,
   674						       size_t header_size)
   675	{
   676		bool use_bufring = ent->queue->use_bufring;
   677		int err = 0;
   678	
   679		if (use_bufring) {
   680			struct iov_iter iter;
   681	
   682			err =  get_kernel_ring_header(ent, type, &iter);
   683			if (err)
   684				goto done;
   685	
   686			if (copy_to_iter(header, header_size, &iter) != header_size)
   687				err = -EFAULT;
   688		} else {
   689			void __user *ring = get_user_ring_header(ent, type);
   690	
   691			if (!ring) {
   692				err = -EINVAL;
   693				goto done;
   694			}
   695	
   696			if (copy_to_user(ring, header, header_size))
   697				err = -EFAULT;
   698		}
   699	
   700	done:
   701		if (err)
   702			pr_info_ratelimited("Copying header to ring failed: "
   703					    "header_type=%u, header_size=%lu, "
 > 704					    "use_bufring=%d\n", type, header_size,
   705					    use_bufring);
   706	
   707		return err;
   708	}
   709	

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