[remoteproc:rpmsg-next 6/6] samples/rpmsg/rpmsg_client_sample.c:68:59: warning: format specifies type 'long' but the argument has type 'ssize_t' (aka 'int')

[remoteproc:rpmsg-next 6/6] samples/rpmsg/rpmsg_client_sample.c:68:59: warning: format specifies type 'long' but the argument has type 'ssize_t' (aka 'int')

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/remoteproc/linux.git rpmsg-next
head:   1029c89bafc714c1b987f29e3bc124a7b63d28d5
commit: 1029c89bafc714c1b987f29e3bc124a7b63d28d5 [6/6] samples: rpmsg: Add MTU size info
config: i386-randconfig-063-20260907 (https://download.01.org/0day-ci/archive/20260907/202609072042.wraEH9fu-lkp@intel.com/config)
compiler: clang version 22.1.3 (https://github.com/llvm/llvm-project e9846648fd6183ee6d8cbdb4502213fcf902a211)
sparse: v0.6.5-rc1
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260907/202609072042.wraEH9fu-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/202609072042.wraEH9fu-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> samples/rpmsg/rpmsg_client_sample.c:68:59: warning: format specifies type 'long' but the argument has type 'ssize_t' (aka 'int') [-Wformat]
      68 |                 dev_warn(&rpdev->dev, "invalid rpmsg MTU size = %ld\n", mtu);
         |                                                                 ~~~     ^~~
         |                                                                 %zd
   include/linux/dev_printk.h:156:70: note: expanded from macro 'dev_warn'
     156 |         dev_printk_index_wrap(_dev_warn, KERN_WARNING, dev, dev_fmt(fmt), ##__VA_ARGS__)
         |                                                                     ~~~     ^~~~~~~~~~~
   include/linux/dev_printk.h:110:23: note: expanded from macro 'dev_printk_index_wrap'
     110 |                 _p_func(dev, fmt, ##__VA_ARGS__);                       \
         |                              ~~~    ^~~~~~~~~~~
   samples/rpmsg/rpmsg_client_sample.c:72:50: warning: format specifies type 'long' but the argument has type 'ssize_t' (aka 'int') [-Wformat]
      72 |         dev_info(&rpdev->dev, "rpmsg MTU size = %ld\n", mtu);
         |                                                 ~~~     ^~~
         |                                                 %zd
   include/linux/dev_printk.h:160:67: note: expanded from macro 'dev_info'
     160 |         dev_printk_index_wrap(_dev_info, KERN_INFO, dev, dev_fmt(fmt), ##__VA_ARGS__)
         |                                                                  ~~~     ^~~~~~~~~~~
   include/linux/dev_printk.h:110:23: note: expanded from macro 'dev_printk_index_wrap'
     110 |                 _p_func(dev, fmt, ##__VA_ARGS__);                       \
         |                              ~~~    ^~~~~~~~~~~
   samples/rpmsg/rpmsg_client_sample.c:79:17: warning: format specifies type 'long' but the argument has type 'ssize_t' (aka 'int') [-Wformat]
      78 |                         "message size %zu exceeds rpmsg MTU size %ld\n",
         |                                                                  ~~~
         |                                                                  %zd
      79 |                         strlen(MSG), mtu);
         |                                      ^~~
   include/linux/dev_printk.h:154:65: note: expanded from macro 'dev_err'
     154 |         dev_printk_index_wrap(_dev_err, KERN_ERR, dev, dev_fmt(fmt), ##__VA_ARGS__)
         |                                                                ~~~     ^~~~~~~~~~~
   include/linux/dev_printk.h:110:23: note: expanded from macro 'dev_printk_index_wrap'
     110 |                 _p_func(dev, fmt, ##__VA_ARGS__);                       \
         |                              ~~~    ^~~~~~~~~~~
   3 warnings generated.


vim +68 samples/rpmsg/rpmsg_client_sample.c

    50	
    51	static int rpmsg_sample_probe(struct rpmsg_device *rpdev)
    52	{
    53		int ret;
    54		struct instance_data *idata;
    55		ssize_t mtu, msg_len;
    56	
    57		dev_info(&rpdev->dev, "new channel: 0x%x -> 0x%x!\n",
    58						rpdev->src, rpdev->dst);
    59	
    60		idata = devm_kzalloc(&rpdev->dev, sizeof(*idata), GFP_KERNEL);
    61		if (!idata)
    62			return -ENOMEM;
    63	
    64		dev_set_drvdata(&rpdev->dev, idata);
    65	
    66		mtu = rpmsg_get_mtu(rpdev->ept);
    67		if (mtu < 0) {
  > 68			dev_warn(&rpdev->dev, "invalid rpmsg MTU size = %ld\n", mtu);
    69			return mtu;
    70		}
    71	
    72		dev_info(&rpdev->dev, "rpmsg MTU size = %ld\n", mtu);
    73	
    74		msg_len = strlen(MSG);
    75		/* make sure our message fits in a single rpmsg buffer */
    76		if (msg_len > mtu) {
    77			dev_err(&rpdev->dev,
    78				"message size %zu exceeds rpmsg MTU size %ld\n",
    79				strlen(MSG), mtu);
    80			return -EMSGSIZE;
    81		}
    82	
    83		/* send a message to our remote processor */
    84		ret = rpmsg_send(rpdev->ept, MSG, msg_len);
    85		if (ret) {
    86			dev_err(&rpdev->dev, "rpmsg_send failed: %d\n", ret);
    87			return ret;
    88		}
    89	
    90		return 0;
    91	}
    92	

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