[PATCH] soundwire: qcom: use signed variable for error return
We get warning for using a unsigned variable being compared to less than zero. The comparison is correct as it checks for errors from previous call to qcom_swrm_get_alert_slave_dev_num(), so we should use a signed variable instead.
drivers/soundwire/qcom.c: qcom_swrm_irq_handler() warn: impossible condition '(devnum < 0) => (0-255 < 0)'
Reported-by: kernel test robot lkp@intel.com Signed-off-by: Vinod Koul vkoul@kernel.org --- drivers/soundwire/qcom.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/soundwire/qcom.c b/drivers/soundwire/qcom.c index b08ecb9b418c..55ed133c6704 100644 --- a/drivers/soundwire/qcom.c +++ b/drivers/soundwire/qcom.c @@ -428,7 +428,7 @@ static irqreturn_t qcom_swrm_irq_handler(int irq, void *dev_id) struct qcom_swrm_ctrl *swrm = dev_id; u32 value, intr_sts, intr_sts_masked, slave_status; u32 i; - u8 devnum = 0; + s8 devnum = 0; int ret = IRQ_HANDLED;
swrm->reg_read(swrm, SWRM_INTERRUPT_STATUS, &intr_sts);
On 3/31/21 2:21 AM, Vinod Koul wrote:
We get warning for using a unsigned variable being compared to less than zero. The comparison is correct as it checks for errors from previous call to qcom_swrm_get_alert_slave_dev_num(), so we should use a signed variable instead.
drivers/soundwire/qcom.c: qcom_swrm_irq_handler() warn: impossible condition '(devnum < 0) => (0-255 < 0)'
Reported-by: kernel test robot lkp@intel.com Signed-off-by: Vinod Koul vkoul@kernel.org
drivers/soundwire/qcom.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/soundwire/qcom.c b/drivers/soundwire/qcom.c index b08ecb9b418c..55ed133c6704 100644 --- a/drivers/soundwire/qcom.c +++ b/drivers/soundwire/qcom.c @@ -428,7 +428,7 @@ static irqreturn_t qcom_swrm_irq_handler(int irq, void *dev_id) struct qcom_swrm_ctrl *swrm = dev_id; u32 value, intr_sts, intr_sts_masked, slave_status; u32 i;
- u8 devnum = 0;
- s8 devnum = 0;
it's not great to store negative error codes with s8. That works in this specific case because the function only returns -EINVAL.
We actually have zero occurrences of s8 in the drivers/soundwire/ code.
int ret = IRQ_HANDLED;
swrm->reg_read(swrm, SWRM_INTERRUPT_STATUS, &intr_sts);
On 31-03-21, 09:41, Pierre-Louis Bossart wrote:
On 3/31/21 2:21 AM, Vinod Koul wrote:
We get warning for using a unsigned variable being compared to less than zero. The comparison is correct as it checks for errors from previous call to qcom_swrm_get_alert_slave_dev_num(), so we should use a signed variable instead.
drivers/soundwire/qcom.c: qcom_swrm_irq_handler() warn: impossible condition '(devnum < 0) => (0-255 < 0)'
Reported-by: kernel test robot lkp@intel.com Signed-off-by: Vinod Koul vkoul@kernel.org
drivers/soundwire/qcom.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/soundwire/qcom.c b/drivers/soundwire/qcom.c index b08ecb9b418c..55ed133c6704 100644 --- a/drivers/soundwire/qcom.c +++ b/drivers/soundwire/qcom.c @@ -428,7 +428,7 @@ static irqreturn_t qcom_swrm_irq_handler(int irq, void *dev_id) struct qcom_swrm_ctrl *swrm = dev_id; u32 value, intr_sts, intr_sts_masked, slave_status; u32 i;
- u8 devnum = 0;
- s8 devnum = 0;
it's not great to store negative error codes with s8. That works in this specific case because the function only returns -EINVAL.
Yeah I did check EINVAL was the case which would work but in general I agree that makes sense, I discussed with Srini on IRC and looks like I havent posted v2, should hit the pipes shortly
On Wed 31 Mar 02:21 CDT 2021, Vinod Koul wrote:
We get warning for using a unsigned variable being compared to less than zero. The comparison is correct as it checks for errors from previous call to qcom_swrm_get_alert_slave_dev_num(), so we should use a signed variable instead.
drivers/soundwire/qcom.c: qcom_swrm_irq_handler() warn: impossible condition '(devnum < 0) => (0-255 < 0)'
Reported-by: kernel test robot lkp@intel.com Signed-off-by: Vinod Koul vkoul@kernel.org
drivers/soundwire/qcom.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/soundwire/qcom.c b/drivers/soundwire/qcom.c index b08ecb9b418c..55ed133c6704 100644 --- a/drivers/soundwire/qcom.c +++ b/drivers/soundwire/qcom.c @@ -428,7 +428,7 @@ static irqreturn_t qcom_swrm_irq_handler(int irq, void *dev_id) struct qcom_swrm_ctrl *swrm = dev_id; u32 value, intr_sts, intr_sts_masked, slave_status; u32 i;
- u8 devnum = 0;
- s8 devnum = 0;
At least in today's linux-next qcom_swrm_get_alert_slave_dev_num() returns an int and the code only checks to see if this is negative. So it seems like making this a full int ensures there's no truncation etc.
And at least as written today there's no need to initialize the variable.
Regards, Bjorn
int ret = IRQ_HANDLED;
swrm->reg_read(swrm, SWRM_INTERRUPT_STATUS, &intr_sts);
2.26.3
participants (3)
-
Bjorn Andersson -
Pierre-Louis Bossart -
Vinod Koul