[bug report] wifi: ath12k: Add support for reading variant from ACPI to download board data file

[Dan Carpenter <error27@gmail.com>]

Hello Lingbo Kong,

Commit 0a43c3a520e9 ("wifi: ath12k: Add support for reading variant
from ACPI to download board data file") from Jan 13, 2025
(linux-next), leads to the following Smatch static checker warning:

	drivers/net/wireless/ath/ath12k/acpi.c:395 ath12k_acpi_start()
	warn: set error code if 'ab->acpi.bdf_string[0] == 0'

drivers/net/wireless/ath/ath12k/acpi.c
    351 int ath12k_acpi_start(struct ath12k_base *ab)
    352 {
    353         acpi_status status;
    354         int ret;
    355 
    356         ab->acpi.acpi_tas_enable = false;
    357         ab->acpi.acpi_disable_11be = false;
    358         ab->acpi.acpi_disable_rfkill = false;
    359         ab->acpi.acpi_bios_sar_enable = false;
    360         ab->acpi.acpi_cca_enable = false;
    361         ab->acpi.acpi_band_edge_enable = false;
    362         ab->acpi.acpi_enable_bdf = false;
    363         ab->acpi.bdf_string[0] = '\0';
    364 
    365         if (!ab->hw_params->acpi_guid)
    366                 /* not supported with this hardware */
    367                 return 0;
    368 
    369         ret = ath12k_acpi_dsm_get_data(ab, ATH12K_ACPI_DSM_FUNC_SUPPORT_FUNCS);
    370         if (ret) {
    371                 ath12k_dbg(ab, ATH12K_DBG_BOOT, "failed to get ACPI DSM data: %d\n", ret);
    372                 return ret;
    373         }
    374 
    375         if (ATH12K_ACPI_FUNC_BIT_VALID(ab->acpi, ATH12K_ACPI_FUNC_BIT_DISABLE_FLAG)) {
    376                 ret = ath12k_acpi_dsm_get_data(ab, ATH12K_ACPI_DSM_FUNC_DISABLE_FLAG);
    377                 if (ret) {
    378                         ath12k_warn(ab, "failed to get ACPI DISABLE FLAG: %d\n", ret);
    379                         return ret;
    380                 }
    381 
    382                 if (ATH12K_ACPI_CHEK_BIT_VALID(ab->acpi,
    383                                                ATH12K_ACPI_DSM_DISABLE_11BE_BIT))
    384                         ab->acpi.acpi_disable_11be = true;
    385 
    386                 if (!ATH12K_ACPI_CHEK_BIT_VALID(ab->acpi,
    387                                                 ATH12K_ACPI_DSM_DISABLE_RFKILL_BIT))
    388                         ab->acpi.acpi_disable_rfkill = true;
    389         }
    390 
    391         if (ATH12K_ACPI_FUNC_BIT_VALID(ab->acpi, ATH12K_ACPI_FUNC_BIT_BDF_EXT)) {
    392                 ret = ath12k_acpi_dsm_get_data(ab, ATH12K_ACPI_DSM_FUNC_BDF_EXT);
    393                 if (ret || ab->acpi.bdf_string[0] == '\0') {
                                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Should we set the error code for an empty string?

    394                         ath12k_warn(ab, "failed to get ACPI BDF EXT: %d\n", ret);
--> 395                         return ret;
    396                 }
    397 
    398                 ab->acpi.acpi_enable_bdf = true;
    399         }
    400 
    401         if (ATH12K_ACPI_FUNC_BIT_VALID(ab->acpi, ATH12K_ACPI_FUNC_BIT_TAS_CFG)) {
    402                 ret = ath12k_acpi_dsm_get_data(ab, ATH12K_ACPI_DSM_FUNC_TAS_CFG);
    403                 if (ret) {
    404                         ath12k_warn(ab, "failed to get ACPI TAS config table: %d\n", ret);

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regards,
dan carpenter