[xilinx-xlnx:xlnx_rebase_v5.15_LTS 304/1079] drivers/tty/serial/xilinx_uartps.c:1518 cdns_get_id() warn: inconsistent returns '&bitmap_lock'.

[xilinx-xlnx:xlnx_rebase_v5.15_LTS 304/1079] drivers/tty/serial/xilinx_uartps.c:1518 cdns_get_id() warn: inconsistent returns '&bitmap_lock'.

[Dan Carpenter]

tree:   https://github.com/Xilinx/linux-xlnx xlnx_rebase_v5.15_LTS
head:   26346d468f90100952de38511adf57513f801cf7
commit: f0090478ae8a76b733a846f50dc5559fff3c461f [304/1079] serial: uartps: Change uart ID port allocation
config: powerpc64-randconfig-m031-20220405 (https://download.01.org/0day-ci/archive/20220406/202204061608.ed0SVSJO-lkp@intel.com/config)
compiler: powerpc64-linux-gcc (GCC) 11.2.0

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>

smatch warnings:
drivers/tty/serial/xilinx_uartps.c:1518 cdns_get_id() warn: inconsistent returns '&bitmap_lock'.

vim +1518 drivers/tty/serial/xilinx_uartps.c

f0090478ae8a76b Michal Simek 2018-09-20  1454  static int cdns_get_id(struct platform_device *pdev)
f0090478ae8a76b Michal Simek 2018-09-20  1455  {
f0090478ae8a76b Michal Simek 2018-09-20  1456  	int id, ret;
f0090478ae8a76b Michal Simek 2018-09-20  1457  
f0090478ae8a76b Michal Simek 2018-09-20  1458  	mutex_lock(&bitmap_lock);
f0090478ae8a76b Michal Simek 2018-09-20  1459  
f0090478ae8a76b Michal Simek 2018-09-20  1460  	/* Alias list is stable that's why get alias bitmap only once */
f0090478ae8a76b Michal Simek 2018-09-20  1461  	if (!alias_bitmap_initialized) {
f0090478ae8a76b Michal Simek 2018-09-20  1462  		ret = of_alias_get_alias_list(cdns_uart_of_match, "serial",
f0090478ae8a76b Michal Simek 2018-09-20  1463  					      alias_bitmap, CDNS_UART_NR_PORTS);
f0090478ae8a76b Michal Simek 2018-09-20  1464  		if (ret)
f0090478ae8a76b Michal Simek 2018-09-20  1465  			return ret;

Missing mutex_unlock(&bitmap_lock);

f0090478ae8a76b Michal Simek 2018-09-20  1466  
f0090478ae8a76b Michal Simek 2018-09-20  1467  		alias_bitmap_initialized++;
f0090478ae8a76b Michal Simek 2018-09-20  1468  	}
f0090478ae8a76b Michal Simek 2018-09-20  1469  
f0090478ae8a76b Michal Simek 2018-09-20  1470  	/* Make sure that alias ID is not taken by instance without alias */
f0090478ae8a76b Michal Simek 2018-09-20  1471  	bitmap_or(bitmap, bitmap, alias_bitmap, CDNS_UART_NR_PORTS);
f0090478ae8a76b Michal Simek 2018-09-20  1472  
f0090478ae8a76b Michal Simek 2018-09-20  1473  	dev_dbg(&pdev->dev, "Alias bitmap: %*pb\n",
f0090478ae8a76b Michal Simek 2018-09-20  1474  		CDNS_UART_NR_PORTS, bitmap);
f0090478ae8a76b Michal Simek 2018-09-20  1475  
f0090478ae8a76b Michal Simek 2018-09-20  1476  	/* Look for a serialN alias */
f0090478ae8a76b Michal Simek 2018-09-20  1477  	id = of_alias_get_id(pdev->dev.of_node, "serial");
f0090478ae8a76b Michal Simek 2018-09-20  1478  	if (id < 0) {
f0090478ae8a76b Michal Simek 2018-09-20  1479  		dev_warn(&pdev->dev,
f0090478ae8a76b Michal Simek 2018-09-20  1480  			 "No serial alias passed. Using the first free id\n");
f0090478ae8a76b Michal Simek 2018-09-20  1481  
f0090478ae8a76b Michal Simek 2018-09-20  1482  		/*
f0090478ae8a76b Michal Simek 2018-09-20  1483  		 * Start with id 0 and check if there is no serial0 alias
f0090478ae8a76b Michal Simek 2018-09-20  1484  		 * which points to device which is compatible with this driver.
f0090478ae8a76b Michal Simek 2018-09-20  1485  		 * If alias exists then try next free position.
f0090478ae8a76b Michal Simek 2018-09-20  1486  		 */
f0090478ae8a76b Michal Simek 2018-09-20  1487  		id = 0;
f0090478ae8a76b Michal Simek 2018-09-20  1488  
f0090478ae8a76b Michal Simek 2018-09-20  1489  		for (;;) {
f0090478ae8a76b Michal Simek 2018-09-20  1490  			dev_info(&pdev->dev, "Checking id %d\n", id);
f0090478ae8a76b Michal Simek 2018-09-20  1491  			id = find_next_zero_bit(bitmap, CDNS_UART_NR_PORTS, id);
f0090478ae8a76b Michal Simek 2018-09-20  1492  
f0090478ae8a76b Michal Simek 2018-09-20  1493  			/* No free empty instance */
f0090478ae8a76b Michal Simek 2018-09-20  1494  			if (id == CDNS_UART_NR_PORTS) {
f0090478ae8a76b Michal Simek 2018-09-20  1495  				dev_err(&pdev->dev, "No free ID\n");
f0090478ae8a76b Michal Simek 2018-09-20  1496  				mutex_unlock(&bitmap_lock);
f0090478ae8a76b Michal Simek 2018-09-20  1497  				return -EINVAL;
f0090478ae8a76b Michal Simek 2018-09-20  1498  			}
f0090478ae8a76b Michal Simek 2018-09-20  1499  
f0090478ae8a76b Michal Simek 2018-09-20  1500  			dev_dbg(&pdev->dev, "The empty id is %d\n", id);
f0090478ae8a76b Michal Simek 2018-09-20  1501  			/* Check if ID is empty */
f0090478ae8a76b Michal Simek 2018-09-20  1502  			if (!test_and_set_bit(id, bitmap)) {
f0090478ae8a76b Michal Simek 2018-09-20  1503  				/* Break the loop if bit is taken */
f0090478ae8a76b Michal Simek 2018-09-20  1504  				dev_dbg(&pdev->dev,
f0090478ae8a76b Michal Simek 2018-09-20  1505  					"Selected ID %d allocation passed\n",
f0090478ae8a76b Michal Simek 2018-09-20  1506  					id);
f0090478ae8a76b Michal Simek 2018-09-20  1507  				break;
f0090478ae8a76b Michal Simek 2018-09-20  1508  			}
f0090478ae8a76b Michal Simek 2018-09-20  1509  			dev_dbg(&pdev->dev,
f0090478ae8a76b Michal Simek 2018-09-20  1510  				"Selected ID %d allocation failed\n", id);
f0090478ae8a76b Michal Simek 2018-09-20  1511  			/* if taking bit fails then try next one */
f0090478ae8a76b Michal Simek 2018-09-20  1512  			id++;
f0090478ae8a76b Michal Simek 2018-09-20  1513  		}
f0090478ae8a76b Michal Simek 2018-09-20  1514  	}
f0090478ae8a76b Michal Simek 2018-09-20  1515  
f0090478ae8a76b Michal Simek 2018-09-20  1516  	mutex_unlock(&bitmap_lock);
f0090478ae8a76b Michal Simek 2018-09-20  1517  
f0090478ae8a76b Michal Simek 2018-09-20 @1518  	return id;
f0090478ae8a76b Michal Simek 2018-09-20  1519  }

-- 
0-DAY CI Kernel Test Service
https://01.org/lkp


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