| Message ID | 20240101172611.694830-1-jic23@kernel.org (mailing list archive) |
|---|---|
| Headers | show |
| Series | device property / IIO: Use cleanup.h magic for fwnode_handle_put() handling. | expand |
On Mon, Jan 01, 2024 at 05:25:58PM +0000, Jonathan Cameron wrote: > From: Jonathan Cameron <Jonathan.Cameron@huawei.com> > > RFC mainly because it's untested. I have none of the relevant hardware and > haven't yet emulated the firmware descriptions to test this. > I have tested the device tree only version: > https://lore.kernel.org/linux-iio/20231217184648.185236-1-jic23@kernel.org/ > which is very similar. > > Failing to release the references on early exit from loops over child nodes > and similar are a fairly common source of bugs. The need to explicitly > release the references via fwnode_handle_put() also complicate the code. > > The first patch enables > > struct fwnode_handle *child __free(fwnode_handle) = NULL; > > device_for_each_child_node(dev, child) { > if (err) > /* > * Previously needed a fwnode_handle_put() here, > * will now be called automatically as well leave > * the scope within which the cleanup is registered > */ > return err; > } > > /* > * fwnode_handle_put() no automatically called here - but child == NULL so > * that call is a noop > */ > } > > As can be seen by the examples from IIO that follow this can save > a reasonable amount of complexity and boiler plate code, often enabling > additional cleanups in related code such as use of > return dev_err_probe(). Important comment on the first patch, otherwise LGTM.
From: Jonathan Cameron <Jonathan.Cameron@huawei.com> RFC mainly because it's untested. I have none of the relevant hardware and haven't yet emulated the firmware descriptions to test this. I have tested the device tree only version: https://lore.kernel.org/linux-iio/20231217184648.185236-1-jic23@kernel.org/ which is very similar. Failing to release the references on early exit from loops over child nodes and similar are a fairly common source of bugs. The need to explicitly release the references via fwnode_handle_put() also complicate the code. The first patch enables struct fwnode_handle *child __free(fwnode_handle) = NULL; device_for_each_child_node(dev, child) { if (err) /* * Previously needed a fwnode_handle_put() here, * will now be called automatically as well leave * the scope within which the cleanup is registered */ return err; } /* * fwnode_handle_put() no automatically called here - but child == NULL so * that call is a noop */ } As can be seen by the examples from IIO that follow this can save a reasonable amount of complexity and boiler plate code, often enabling additional cleanups in related code such as use of return dev_err_probe(). Jonathan Cameron (13): device property: Add cleanup.h based fwnode_handle_put() scope based cleanup. iio: adc: max11410: Use __free(fwnode_handle) to replace fwnode_handle_put() calls iio: adc: mcp3564: Use __free(fwnode_handle) to replace fwnode_handle_put() calls iio: adc: qcom-spmi-adc5: Use __free(fwnode_handle) to replace fwnode_handle_put() calls iio: adc: rzg2l_adc: Use __free(fwnode_handle) to replace fwnode_handle_put() calls iio: adc: stm32: Use __free(fwnode_handle) to replace fwnode_handle_put() calls iio: adc: ti-ads1015: Use __free(fwnode_handle) to replace fwnode_handle_put() calls iio: adc: ti-ads131e08: Use __free(fwnode_handle) to replace fwnode_handle_put() calls iio: addac: ad74413r: Use __free(fwnode_handle) to replace fwnode_handle_put() calls iio: dac: ad3552: Use __free(fwnode_handle) to replace fwnode_handle_put() calls iio: dac: ad5770r: Use __free(fwnode_handle) to replace fwnode_handle_put() calls iio: dac: ltc2688: Use __free(fwnode_handle) to replace fwnode_handle_put() calls iio: temp: ltc2983: Use __free(fwnode_handle) to replace fwnode_handle_put() calls drivers/iio/adc/max11410.c | 26 ++++-------- drivers/iio/adc/mcp3564.c | 15 ++++--- drivers/iio/adc/qcom-spmi-adc5.c | 6 +-- drivers/iio/adc/rzg2l_adc.c | 10 ++--- drivers/iio/adc/stm32-adc.c | 62 +++++++++++---------------- drivers/iio/adc/ti-ads1015.c | 4 +- drivers/iio/adc/ti-ads131e08.c | 12 ++---- drivers/iio/addac/ad74413r.c | 9 +--- drivers/iio/dac/ad3552r.c | 50 +++++++++------------- drivers/iio/dac/ad5770r.c | 18 +++----- drivers/iio/dac/ltc2688.c | 23 +++------- drivers/iio/temperature/ltc2983.c | 70 ++++++++++--------------------- include/linux/property.h | 2 + 13 files changed, 104 insertions(+), 203 deletions(-)