drivers/soundwire/qcom.c:1319 qcom_swrm_probe() warn: passing zero to 'PTR_ERR'
From: Dan Carpenter
Date: Mon Aug 22 2022 - 03:57:32 EST
tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head: 50cd95ac46548429e5bba7ca75cc97d11a697947
commit: 1fd0d85affe4d64e54b81d04bf9577e57172a341 soundwire: qcom: Add flag for software clock gating check
config: riscv-randconfig-m031-20220819 (https://download.01.org/0day-ci/archive/20220820/202208202132.gxUTdHmB-lkp@xxxxxxxxx/config)
compiler: riscv64-linux-gcc (GCC) 12.1.0
If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <lkp@xxxxxxxxx>
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
New smatch warnings:
drivers/soundwire/qcom.c:1319 qcom_swrm_probe() warn: passing zero to 'PTR_ERR'
Old smatch warnings:
arch/riscv/include/asm/atomic.h:204 arch_atomic_fetch_add_unless() warn: inconsistent indenting
vim +/PTR_ERR +1319 drivers/soundwire/qcom.c
02efb49aa805ce Srinivas Kandagatla 2020-01-13 1280 static int qcom_swrm_probe(struct platform_device *pdev)
02efb49aa805ce Srinivas Kandagatla 2020-01-13 1281 {
02efb49aa805ce Srinivas Kandagatla 2020-01-13 1282 struct device *dev = &pdev->dev;
02efb49aa805ce Srinivas Kandagatla 2020-01-13 1283 struct sdw_master_prop *prop;
02efb49aa805ce Srinivas Kandagatla 2020-01-13 1284 struct sdw_bus_params *params;
02efb49aa805ce Srinivas Kandagatla 2020-01-13 1285 struct qcom_swrm_ctrl *ctrl;
8cb3b4e74cd810 Srinivas Kandagatla 2020-09-17 1286 const struct qcom_swrm_data *data;
02efb49aa805ce Srinivas Kandagatla 2020-01-13 1287 int ret;
02efb49aa805ce Srinivas Kandagatla 2020-01-13 1288 u32 val;
02efb49aa805ce Srinivas Kandagatla 2020-01-13 1289
02efb49aa805ce Srinivas Kandagatla 2020-01-13 1290 ctrl = devm_kzalloc(dev, sizeof(*ctrl), GFP_KERNEL);
02efb49aa805ce Srinivas Kandagatla 2020-01-13 1291 if (!ctrl)
02efb49aa805ce Srinivas Kandagatla 2020-01-13 1292 return -ENOMEM;
02efb49aa805ce Srinivas Kandagatla 2020-01-13 1293
8cb3b4e74cd810 Srinivas Kandagatla 2020-09-17 1294 data = of_device_get_match_data(dev);
8cb3b4e74cd810 Srinivas Kandagatla 2020-09-17 1295 ctrl->rows_index = sdw_find_row_index(data->default_rows);
8cb3b4e74cd810 Srinivas Kandagatla 2020-09-17 1296 ctrl->cols_index = sdw_find_col_index(data->default_cols);
47edc0104c61d6 Vinod Koul 2020-11-25 1297 #if IS_REACHABLE(CONFIG_SLIMBUS)
02efb49aa805ce Srinivas Kandagatla 2020-01-13 1298 if (dev->parent->bus == &slimbus_bus) {
5bd773242f75da Jonathan Marek 2020-09-05 1299 #else
5bd773242f75da Jonathan Marek 2020-09-05 1300 if (false) {
5bd773242f75da Jonathan Marek 2020-09-05 1301 #endif
d1df23fe688b58 Jonathan Marek 2020-09-05 1302 ctrl->reg_read = qcom_swrm_ahb_reg_read;
02efb49aa805ce Srinivas Kandagatla 2020-01-13 1303 ctrl->reg_write = qcom_swrm_ahb_reg_write;
02efb49aa805ce Srinivas Kandagatla 2020-01-13 1304 ctrl->regmap = dev_get_regmap(dev->parent, NULL);
02efb49aa805ce Srinivas Kandagatla 2020-01-13 1305 if (!ctrl->regmap)
02efb49aa805ce Srinivas Kandagatla 2020-01-13 1306 return -EINVAL;
02efb49aa805ce Srinivas Kandagatla 2020-01-13 1307 } else {
82f5c70c26511b Jonathan Marek 2020-09-05 1308 ctrl->reg_read = qcom_swrm_cpu_reg_read;
82f5c70c26511b Jonathan Marek 2020-09-05 1309 ctrl->reg_write = qcom_swrm_cpu_reg_write;
82f5c70c26511b Jonathan Marek 2020-09-05 1310 ctrl->mmio = devm_platform_ioremap_resource(pdev, 0);
82f5c70c26511b Jonathan Marek 2020-09-05 1311 if (IS_ERR(ctrl->mmio))
82f5c70c26511b Jonathan Marek 2020-09-05 1312 return PTR_ERR(ctrl->mmio);
02efb49aa805ce Srinivas Kandagatla 2020-01-13 1313 }
02efb49aa805ce Srinivas Kandagatla 2020-01-13 1314
1fd0d85affe4d6 Srinivasa Rao Mandadapu 2022-07-01 1315 if (data->sw_clk_gate_required) {
1fd0d85affe4d6 Srinivasa Rao Mandadapu 2022-07-01 1316 ctrl->audio_cgcr = devm_reset_control_get_exclusive(dev, "swr_audio_cgcr");
1fd0d85affe4d6 Srinivasa Rao Mandadapu 2022-07-01 1317 if (IS_ERR_OR_NULL(ctrl->audio_cgcr)) {
1fd0d85affe4d6 Srinivasa Rao Mandadapu 2022-07-01 1318 dev_err(dev, "Failed to get cgcr reset ctrl required for SW gating\n");
1fd0d85affe4d6 Srinivasa Rao Mandadapu 2022-07-01 @1319 ret = PTR_ERR(ctrl->audio_cgcr);
I believe that the IS_ERR_OR_NULL() check is wrong because
devm_reset_control_get_exclusive() does not return NULL. That means
that this bug is harmless.
I wrote a blog about this:
https://staticthinking.wordpress.com/2022/08/01/mixing-error-pointers-and-null/
The TLDR; version is that when a function returns both error pointers
and NULLs then the NULL should be treated as a success path. Do not
print an error message. Continue probing the driver but add NULL checks
as necessary to support that the feature can be disabled.
The devm_reset_control_get_exclusive() function calls
__devm_reset_control_get() which *can* return NULL if we pass
"optional == true". But devm_reset_control_get_exclusive() passes
"optional == false" so it is not optional and will either return a valid
pointer or an error pointer.
1fd0d85affe4d6 Srinivasa Rao Mandadapu 2022-07-01 1320 goto err_init;
1fd0d85affe4d6 Srinivasa Rao Mandadapu 2022-07-01 1321 }
1fd0d85affe4d6 Srinivasa Rao Mandadapu 2022-07-01 1322 }
1fd0d85affe4d6 Srinivasa Rao Mandadapu 2022-07-01 1323
02efb49aa805ce Srinivas Kandagatla 2020-01-13 1324 ctrl->irq = of_irq_get(dev->of_node, 0);
91b5cfc0209b63 Pierre-Louis Bossart 2020-04-30 1325 if (ctrl->irq < 0) {
--
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