We're doing some needless string copies when trying to assign the proper `prop` string. We can make `prop` a const char* and simply assign to string literals.
For the case where a format string is used, let's extract the parsing logic out into sx9324_parse_phase_prop(). We no longer need to create copies or allocate new memory. sx9324_parse_phase_prop() will simply return the default def value if it fails. This also cleans up some deprecated strncpy() uses [1]. Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1] Link: https://github.com/KSPP/linux/issues/90 Cc: linux-hardening@vger.kernel.org Signed-off-by: Justin Stitt <justinst...@google.com> --- Changes in v3: - extract logic into sx9324_parse_phase_prop() and use string literals (thanks Stephen) - rebase onto mainline bee0e7762ad2c602 - Link to v2: https://lore.kernel.org/r/20231026-strncpy-drivers-iio-proximity-sx9324-c-v2-1-cee6e5db7...@google.com Changes in v2: - make prop a const char* and do simple assignments (thanks Jonathan) - rebase onto 3a568e3a961ba330 - Link to v1: https://lore.kernel.org/r/20230921-strncpy-drivers-iio-proximity-sx9324-c-v1-1-4e8d28fd1...@google.com --- --- drivers/iio/proximity/sx9324.c | 69 ++++++++++++++++++++++++++---------------- 1 file changed, 43 insertions(+), 26 deletions(-) diff --git a/drivers/iio/proximity/sx9324.c b/drivers/iio/proximity/sx9324.c index 438f9c9aba6e..e3bc30b57b19 100644 --- a/drivers/iio/proximity/sx9324.c +++ b/drivers/iio/proximity/sx9324.c @@ -873,6 +873,32 @@ static int sx9324_init_compensation(struct iio_dev *indio_dev) 20000, 2000000); } +static u32 sx9324_parse_phase_prop(struct device *dev, + struct sx_common_reg_default *reg_def, + int idx, const char *prop) +{ + unsigned int pin_defs[SX9324_NUM_PINS]; + int count, ret, pin; + u8 default_def; + u32 raw = 0; + + default_def = sx9324_default_regs[idx].def; + + count = device_property_count_u32(dev, prop); + if (count != ARRAY_SIZE(pin_defs)) + return default_def; + ret = device_property_read_u32_array(dev, prop, pin_defs, + ARRAY_SIZE(pin_defs)); + if (ret) + return default_def; + + for (pin = 0; pin < SX9324_NUM_PINS; pin++) + raw |= (pin_defs[pin] << (2 * pin)) & + SX9324_REG_AFE_PH0_PIN_MASK(pin); + + return raw; +} + static const struct sx_common_reg_default * sx9324_get_default_reg(struct device *dev, int idx, struct sx_common_reg_default *reg_def) @@ -884,35 +910,30 @@ sx9324_get_default_reg(struct device *dev, int idx, #define SX9324_PIN_DEF "semtech,ph0-pin" #define SX9324_RESOLUTION_DEF "semtech,ph01-resolution" #define SX9324_PROXRAW_DEF "semtech,ph01-proxraw-strength" - unsigned int pin_defs[SX9324_NUM_PINS]; - char prop[] = SX9324_PROXRAW_DEF; + const char *prop = SX9324_PROXRAW_DEF; u32 start = 0, raw = 0, pos = 0; - int ret, count, ph, pin; const char *res; + int ret; memcpy(reg_def, &sx9324_default_regs[idx], sizeof(*reg_def)); sx_common_get_raw_register_config(dev, reg_def); switch (reg_def->reg) { case SX9324_REG_AFE_PH0: + reg_def->def = sx9324_parse_phase_prop(dev, reg_def, idx, + "semtech,ph0-pin"); + break; case SX9324_REG_AFE_PH1: + reg_def->def = sx9324_parse_phase_prop(dev, reg_def, idx, + "semtech,ph1-pin"); + break; case SX9324_REG_AFE_PH2: + reg_def->def = sx9324_parse_phase_prop(dev, reg_def, idx, + "semtech,ph2-pin"); + break; case SX9324_REG_AFE_PH3: - ph = reg_def->reg - SX9324_REG_AFE_PH0; - snprintf(prop, ARRAY_SIZE(prop), "semtech,ph%d-pin", ph); - - count = device_property_count_u32(dev, prop); - if (count != ARRAY_SIZE(pin_defs)) - break; - ret = device_property_read_u32_array(dev, prop, pin_defs, - ARRAY_SIZE(pin_defs)); - if (ret) - break; - - for (pin = 0; pin < SX9324_NUM_PINS; pin++) - raw |= (pin_defs[pin] << (2 * pin)) & - SX9324_REG_AFE_PH0_PIN_MASK(pin); - reg_def->def = raw; + reg_def->def = sx9324_parse_phase_prop(dev, reg_def, idx, + "semtech,ph3-pin"); break; case SX9324_REG_AFE_CTRL0: ret = device_property_read_string(dev, @@ -937,11 +958,9 @@ sx9324_get_default_reg(struct device *dev, int idx, case SX9324_REG_AFE_CTRL4: case SX9324_REG_AFE_CTRL7: if (reg_def->reg == SX9324_REG_AFE_CTRL4) - strncpy(prop, "semtech,ph01-resolution", - ARRAY_SIZE(prop)); + prop = "semtech,ph01-resolution"; else - strncpy(prop, "semtech,ph23-resolution", - ARRAY_SIZE(prop)); + prop = "semtech,ph23-resolution"; ret = device_property_read_u32(dev, prop, &raw); if (ret) @@ -1012,11 +1031,9 @@ sx9324_get_default_reg(struct device *dev, int idx, case SX9324_REG_PROX_CTRL0: case SX9324_REG_PROX_CTRL1: if (reg_def->reg == SX9324_REG_PROX_CTRL0) - strncpy(prop, "semtech,ph01-proxraw-strength", - ARRAY_SIZE(prop)); + prop = "semtech,ph01-proxraw-strength"; else - strncpy(prop, "semtech,ph23-proxraw-strength", - ARRAY_SIZE(prop)); + prop = "semtech,ph23-proxraw-strength"; ret = device_property_read_u32(dev, prop, &raw); if (ret) break; --- base-commit: bee0e7762ad2c6025b9f5245c040fcc36ef2bde8 change-id: 20230921-strncpy-drivers-iio-proximity-sx9324-c-8c3437676039 Best regards, -- Justin Stitt <justinst...@google.com>
