Re: [PATCH 1/3] soc: ti: pruss: do device_node auto cleanup

Jonathan Cameron
2024-05-16T14:41:41Z

On Fri, 10 May 2024 12:43:22 +0530
Kousik Sanagavarapu <five231003@gmail.com> wrote:

> Use scope based cleanup instead of manual of_node_put() calls, hence
> simplifying the handling of error paths at various places.
>
> Suggested-by: Julia Lawall <julia.lawall@inria.fr>
> Signed-off-by: Kousik Sanagavarapu <five231003@gmail.com>
> ---
> drivers/soc/ti/pruss.c | 48 ++++++++++++++----------------------------
> 1 file changed, 16 insertions(+), 32 deletions(-)
>
> diff --git a/drivers/soc/ti/pruss.c b/drivers/soc/ti/pruss.c
> index 24a42e0b645c..8f238d59eca9 100644
> --- a/drivers/soc/ti/pruss.c
> +++ b/drivers/soc/ti/pruss.c
> @@ -381,13 +381,13 @@ static int pruss_clk_mux_setup(struct pruss *pruss, struct clk *clk_mux,
> static int pruss_clk_init(struct pruss *pruss, struct device_node *cfg_node)
> {
> const struct pruss_private_data *data;
> - struct device_node *clks_np;
> struct device *dev = pruss->dev;
> int ret = 0;
>
> data = of_device_get_match_data(dev);
>
> - clks_np = of_get_child_by_name(cfg_node, "clocks");
> + struct device_node *clks_np __free(device_node) =
> + of_get_child_by_name(cfg_node, "clocks");
> if (!clks_np) {
> dev_err(dev, "%pOF is missing its 'clocks' node\n", cfg_node);
> return -ENODEV;
> @@ -398,7 +398,7 @@ static int pruss_clk_init(struct pruss *pruss, struct device_node *cfg_node)
> "coreclk-mux", clks_np);
> if (ret) {
> dev_err(dev, "failed to setup coreclk-mux\n");
> - goto put_clks_node;
> + return ret;

This driver would also benefit from use of dev_err_probe() for all cases
like this that are called only from the probe() callback.
return dev_err_probe(dev, ret, "failed to setup coreclk-mux\n2);

Handles any deferred cases nicely, but in general simplifies code by
making these printer error message and return cases a single line.

> }
> }
>
> @@ -406,13 +406,10 @@ static int pruss_clk_init(struct pruss *pruss, struct device_node *cfg_node)
> clks_np);
> if (ret) {
> dev_err(dev, "failed to setup iepclk-mux\n");
> - goto put_clks_node;
> + return ret;
> }
>
> -put_clks_node:
> - of_node_put(clks_np);
> -
> - return ret;
> + return 0;
> }
>
> static struct regmap_config regmap_conf = {
> @@ -424,26 +421,22 @@ static struct regmap_config regmap_conf = {
> static int pruss_cfg_of_init(struct device *dev, struct pruss *pruss)
> {
> struct device_node *np = dev_of_node(dev);
> - struct device_node *child;
> + struct device_node *child __free(device_node) =
> + of_get_child_by_name(np, "cfg");
> struct resource res;
> int ret;
>
> - child = of_get_child_by_name(np, "cfg");
> if (!child) {
> dev_err(dev, "%pOF is missing its 'cfg' node\n", child);
> return -ENODEV;
> }
>
> - if (of_address_to_resource(child, 0, &res)) {
> - ret = -ENOMEM;
> - goto node_put;
> - }
> + if (of_address_to_resource(child, 0, &res))
> + return -ENOMEM;
>
> pruss->cfg_base = devm_ioremap(dev, res.start, resource_size(&res));
> - if (!pruss->cfg_base) {
> - ret = -ENOMEM;
> - goto node_put;
> - }
> + if (!pruss->cfg_base)
> + return -ENOMEM;
>
> regmap_conf.name = kasprintf(GFP_KERNEL, "%pOFn@%llx", child,
> (u64)res.start);
> @@ -455,16 +448,13 @@ static int pruss_cfg_of_init(struct device *dev, struct pruss *pruss)
> if (IS_ERR(pruss->cfg_regmap)) {
> dev_err(dev, "regmap_init_mmio failed for cfg, ret = %ld\n",
> PTR_ERR(pruss->cfg_regmap));
> - ret = PTR_ERR(pruss->cfg_regmap);
> - goto node_put;
> + return PTR_ERR(pruss->cfg_regmap);
> }
>
> ret = pruss_clk_init(pruss, child);
> if (ret)
> dev_err(dev, "pruss_clk_init failed, ret = %d\n", ret);
>
> -node_put:
> - of_node_put(child);
> return ret;
> }
>
> @@ -472,7 +462,6 @@ static int pruss_probe(struct platform_device *pdev)
> {
> struct device *dev = &pdev->dev;
> struct device_node *np = dev_of_node(dev);
> - struct device_node *child;
> struct pruss *pruss;
> struct resource res;
> int ret, i, index;
> @@ -494,7 +483,8 @@ static int pruss_probe(struct platform_device *pdev)
> pruss->dev = dev;
> mutex_init(&pruss->lock);
>
> - child = of_get_child_by_name(np, "memories");
> + struct device_node *child __free(device_node) =
> + of_get_child_by_name(np, "memories");

In this case, the scope of the device_node being held is increased quite
a bit. Whilst that shouldn't be a problem, it is a bit ugly.

Perhaps factor this code out into another function similar to the ones above?

Jonathan

> if (!child) {
> dev_err(dev, "%pOF is missing its 'memories' node\n", child);
> return -ENODEV;
> @@ -510,22 +500,17 @@ static int pruss_probe(struct platform_device *pdev)
>
> index = of_property_match_string(child, "reg-names",
> mem_names[i]);
> - if (index < 0) {
> - of_node_put(child);
> + if (index < 0)
> return index;
> - }
>
> - if (of_address_to_resource(child, index, &res)) {
> - of_node_put(child);
> + if (of_address_to_resource(child, index, &res))
> return -EINVAL;
> - }
>
> pruss->mem_regions[i].va = devm_ioremap(dev, res.start,
> resource_size(&res));
> if (!pruss->mem_regions[i].va) {
> dev_err(dev, "failed to parse and map memory resource %d %s\n",
> i, mem_names[i]);
> - of_node_put(child);
> return -ENOMEM;
> }
> pruss->mem_regions[i].pa = res.start;
> @@ -535,7 +520,6 @@ static int pruss_probe(struct platform_device *pdev)
> mem_names[i], &pruss->mem_regions[i].pa,
> pruss->mem_regions[i].size, pruss->mem_regions[i].va);
> }
> - of_node_put(child);
>
> platform_set_drvdata(pdev, pruss);
>