[PATCH v6 1/2] tty: hvc: pass DMA capable memory to put_chars()

[kernel test robot]

Hi Xianting,

Thank you for the patch! Perhaps something to improve:

[auto build test WARNING on tty/tty-testing]
[also build test WARNING on char-misc/char-misc-testing soc/for-next v5.14-rc5 next-20210812]
[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]

url:    https://github.com/0day-ci/linux/commits/Xianting-Tian/make-hvc-pass-dma-capable-memory-to-its-backend/20210812-174847
base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git tty-testing
config: hexagon-randconfig-r041-20210812 (attached as .config)
compiler: clang version 12.0.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/9f2925b5429149ceb0ea6eeaa8c81d422c3124fc
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Xianting-Tian/make-hvc-pass-dma-capable-memory-to-its-backend/20210812-174847
        git checkout 9f2925b5429149ceb0ea6eeaa8c81d422c3124fc
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=hexagon 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp at intel.com>

All warnings (new ones prefixed by >>):

>> drivers/tty/hvc/hvc_console.c:190:26: warning: variable 'hp' is uninitialized when used here [-Wuninitialized]
           spin_unlock_irqrestore(&hp->c_lock, flags);
                                   ^~
   drivers/tty/hvc/hvc_console.c:149:23: note: initialize the variable 'hp' to silence this warning
           struct hvc_struct *hp;
                                ^
                                 = NULL
   1 warning generated.


vim +/hp +190 drivers/tty/hvc/hvc_console.c

   136	
   137	/*
   138	 * Console APIs, NOT TTY.  These APIs are available immediately when
   139	 * hvc_console_setup() finds adapters.
   140	 */
   141	
   142	static void hvc_console_print(struct console *co, const char *b,
   143				      unsigned count)
   144	{
   145		char *c;
   146		unsigned i = 0, n = 0;
   147		int r, donecr = 0, index = co->index;
   148		unsigned long flags;
   149		struct hvc_struct *hp;
   150	
   151		/* Console access attempt outside of acceptable console range. */
   152		if (index >= MAX_NR_HVC_CONSOLES)
   153			return;
   154	
   155		/* This console adapter was removed so it is not usable. */
   156		if (vtermnos[index] == -1 || !cons_outbuf[index])
   157			return;
   158	
   159		c = cons_outbuf[index];
   160	
   161		spin_lock_irqsave(&hp->c_lock, flags);
   162		while (count > 0 || i > 0) {
   163			if (count > 0 && i < sizeof(c)) {
   164				if (b[n] == '\n' && !donecr) {
   165					c[i++] = '\r';
   166					donecr = 1;
   167				} else {
   168					c[i++] = b[n++];
   169					donecr = 0;
   170					--count;
   171				}
   172			} else {
   173				r = cons_ops[index]->put_chars(vtermnos[index], c, i);
   174				if (r <= 0) {
   175					/* throw away characters on error
   176					 * but spin in case of -EAGAIN */
   177					if (r != -EAGAIN) {
   178						i = 0;
   179					} else {
   180						hvc_console_flush(cons_ops[index],
   181							      vtermnos[index]);
   182					}
   183				} else if (r > 0) {
   184					i -= r;
   185					if (i > 0)
   186						memmove(c, c+r, i);
   187				}
   188			}
   189		}
 > 190		spin_unlock_irqrestore(&hp->c_lock, flags);
   191		hvc_console_flush(cons_ops[index], vtermnos[index]);
   192	}
   193	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
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