2023-11-25 18:53:44

by Marcus Folkesson

Subject: [PATCH] iio: adc: mcp3911: simplify code with guard macro

Use the guard(mutex) macro for handle mutex lock/unlocks.

Signed-off-by: Marcus Folkesson <[email protected]>
---
drivers/iio/adc/mcp3911.c | 10 ++++------
1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/drivers/iio/adc/mcp3911.c b/drivers/iio/adc/mcp3911.c
index 974c5bd923a6..85bb13eb6f3b 100644
--- a/drivers/iio/adc/mcp3911.c
+++ b/drivers/iio/adc/mcp3911.c
@@ -7,6 +7,7 @@
*/
#include <linux/bitfield.h>
#include <linux/bits.h>
+#include <linux/cleanup.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/err.h>
@@ -168,7 +169,7 @@ static int mcp3911_read_raw(struct iio_dev *indio_dev,
struct mcp3911 *adc = iio_priv(indio_dev);
int ret = -EINVAL;

- mutex_lock(&adc->lock);
+ guard(mutex)(&adc->lock);
switch (mask) {
case IIO_CHAN_INFO_RAW:
ret = mcp3911_read(adc,
@@ -207,7 +208,6 @@ static int mcp3911_read_raw(struct iio_dev *indio_dev,
}

out:
- mutex_unlock(&adc->lock);
return ret;
}

@@ -218,7 +218,7 @@ static int mcp3911_write_raw(struct iio_dev *indio_dev,
struct mcp3911 *adc = iio_priv(indio_dev);
int ret = -EINVAL;

- mutex_lock(&adc->lock);
+ guard(mutex)(&adc->lock);
switch (mask) {
case IIO_CHAN_INFO_SCALE:
for (int i = 0; i < MCP3911_NUM_SCALES; i++) {
@@ -263,7 +263,6 @@ static int mcp3911_write_raw(struct iio_dev *indio_dev,
}

out:
- mutex_unlock(&adc->lock);
return ret;
}

@@ -350,7 +349,7 @@ static irqreturn_t mcp3911_trigger_handler(int irq, void *p)
int i = 0;
int ret;

- mutex_lock(&adc->lock);
+ guard(mutex)(&adc->lock);
adc->tx_buf = MCP3911_REG_READ(MCP3911_CHANNEL(0), adc->dev_addr);
ret = spi_sync_transfer(adc->spi, xfer, ARRAY_SIZE(xfer));
if (ret < 0) {
@@ -368,7 +367,6 @@ static irqreturn_t mcp3911_trigger_handler(int irq, void *p)
iio_push_to_buffers_with_timestamp(indio_dev, &adc->scan,
iio_get_time_ns(indio_dev));
out:
- mutex_unlock(&adc->lock);
iio_trigger_notify_done(indio_dev->trig);

return IRQ_HANDLED;

---
base-commit: ffc253263a1375a65fa6c9f62a893e9767fbebfa
change-id: 20231125-mcp3911-guard-866591e2c947

Best regards,
--
Marcus Folkesson <[email protected]>

2023-11-26 18:09:53

by Jonathan Cameron

Subject: Re: [PATCH] iio: adc: mcp3911: simplify code with guard macro

On Sat, 25 Nov 2023 19:57:24 +0100
Marcus Folkesson <[email protected]> wrote:

> Use the guard(mutex) macro for handle mutex lock/unlocks.
>
> Signed-off-by: Marcus Folkesson <[email protected]>
Hi Marcus,

Great to see this being used, but there is a little more you can do
here to take advantage fully.

> ---
> drivers/iio/adc/mcp3911.c | 10 ++++------
> 1 file changed, 4 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/iio/adc/mcp3911.c b/drivers/iio/adc/mcp3911.c
> index 974c5bd923a6..85bb13eb6f3b 100644
> --- a/drivers/iio/adc/mcp3911.c
> +++ b/drivers/iio/adc/mcp3911.c
> @@ -7,6 +7,7 @@
> */
> #include <linux/bitfield.h>
> #include <linux/bits.h>
> +#include <linux/cleanup.h>
> #include <linux/clk.h>
> #include <linux/delay.h>
> #include <linux/err.h>
> @@ -168,7 +169,7 @@ static int mcp3911_read_raw(struct iio_dev *indio_dev,
> struct mcp3911 *adc = iio_priv(indio_dev);
> int ret = -EINVAL;
>
> - mutex_lock(&adc->lock);
> + guard(mutex)(&adc->lock);
> switch (mask) {
> case IIO_CHAN_INFO_RAW:
> ret = mcp3911_read(adc,
> @@ -207,7 +208,6 @@ static int mcp3911_read_raw(struct iio_dev *indio_dev,
> }
>
> out:
> - mutex_unlock(&adc->lock);
> return ret;
No point in having the label down here after the change. Just return directly
wherever you see an error.

Same for other cases.

> }
>
> @@ -218,7 +218,7 @@ static int mcp3911_write_raw(struct iio_dev *indio_dev,
> struct mcp3911 *adc = iio_priv(indio_dev);
> int ret = -EINVAL;
>
> - mutex_lock(&adc->lock);
> + guard(mutex)(&adc->lock);
> switch (mask) {
> case IIO_CHAN_INFO_SCALE:
> for (int i = 0; i < MCP3911_NUM_SCALES; i++) {
> @@ -263,7 +263,6 @@ static int mcp3911_write_raw(struct iio_dev *indio_dev,
> }
>
> out:
> - mutex_unlock(&adc->lock);
> return ret;
> }
>
> @@ -350,7 +349,7 @@ static irqreturn_t mcp3911_trigger_handler(int irq, void *p)
> int i = 0;
> int ret;
>
> - mutex_lock(&adc->lock);
> + guard(mutex)(&adc->lock);
> adc->tx_buf = MCP3911_REG_READ(MCP3911_CHANNEL(0), adc->dev_addr);
> ret = spi_sync_transfer(adc->spi, xfer, ARRAY_SIZE(xfer));
> if (ret < 0) {
> @@ -368,7 +367,6 @@ static irqreturn_t mcp3911_trigger_handler(int irq, void *p)
> iio_push_to_buffers_with_timestamp(indio_dev, &adc->scan,
> iio_get_time_ns(indio_dev));
> out:
> - mutex_unlock(&adc->lock);
> iio_trigger_notify_done(indio_dev->trig);
>
> return IRQ_HANDLED;
>
> ---
> base-commit: ffc253263a1375a65fa6c9f62a893e9767fbebfa
> change-id: 20231125-mcp3911-guard-866591e2c947
>
> Best regards,