Hi Piotr,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on remoteproc/rpmsg-next]
[also build test WARNING on linus/master v6.2-rc1 next-20221226]
[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/Piotr-Wojtaszczyk/rpmsg-char-Use-preallocated-SKBs/20221206-174127
base:   git://git.kernel.org/pub/scm/linux/kernel/git/remoteproc/linux.git rpmsg-next
patch link:    https://lore.kernel.org/r/20221206093840.32181-1-piotr.wojtaszczyk%40timesys.com
patch subject: [PATCH] rpmsg: char: Use preallocated SKBs.
config: microblaze-randconfig-s031-20221225
compiler: microblaze-linux-gcc (GCC) 12.1.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # apt-get install sparse
        # sparse version: v0.6.4-39-gce1a6720-dirty
        # https://github.com/intel-lab-lkp/linux/commit/335fb72a363aa6cf77c1b6bf3163e6d175c3110f
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Piotr-Wojtaszczyk/rpmsg-char-Use-preallocated-SKBs/20221206-174127
        git checkout 335fb72a363aa6cf77c1b6bf3163e6d175c3110f
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=microblaze olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=microblaze SHELL=/bin/bash drivers/rpmsg/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>

sparse warnings: (new ones prefixed by >>)
>> drivers/rpmsg/rpmsg_char.c:89:21: sparse: sparse: Using plain integer as NULL pointer
>> drivers/rpmsg/rpmsg_char.c:89:21: sparse: sparse: Using plain integer as NULL pointer

vim +89 drivers/rpmsg/rpmsg_char.c

    84	
    85	static inline
    86	void rpmsg_eptdev_put_skb(struct rpmsg_eptdev *eptdev, struct sk_buff *skb)
    87	{
    88		/* Recycle the skb */
  > 89		skb->tail = 0;
    90		skb->len = 0;
    91		skb_queue_head(&eptdev->skb_pool, skb);
    92	}
    93	

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