[RFC PATCH v3] clk: Use new helper in managed functions

* [RFC PATCH v3] clk: Use new helper in managed functions
@ 2020-01-24 16:16 Marc Gonzalez
  2020-02-07 12:54 ` Marc Gonzalez
  0 siblings, 1 reply; 2+ messages in thread
From: Marc Gonzalez @ 2020-01-24 16:16 UTC (permalink / raw)
  To: linux-clk, Linux ARM, LKML
  Cc: Stephen Boyd, Michael Turquette, Kuninori Morimoto, Russell King,
	Sudip Mukherjee, Dmitry Torokhov, Guenter Roeck, Bjorn Andersson,
	Robin Murphy, Geert Uytterhoeven, Arnd Bergmann, Ard Biesheuvel,
	Greg Kroah-Hartman, Rafael Wysocki, Suzuki Poulose, Mark Rutland

Introduce devm_add() to factorize devres_alloc/devres_add calls.

Using that helper produces simpler code, and smaller object size.
E.g. with gcc-arm-9.2-2019.12-x86_64-aarch64-none-linux-gnu:

    text	   data	    bss	    dec	    hex	filename
-   1708	     80	      0	   1788	    6fc	drivers/clk/clk-devres.o
+   1524	     80	      0	   1604	    644	drivers/clk/clk-devres.o

Signed-off-by: Marc Gonzalez <marc.w.gonzalez@free.fr>
---
Differences from v2 to v3
x Make devm_add() return an error-code rather than the raw data pointer
  (in case devres_alloc ever returns an ERR_PTR) as suggested by Geert
x Provide a variadic version devm_vadd() to work with structs as suggested
  by Geert
x Don't use nested ifs in clk_devm* implementations (hopefully simpler
  code logic to follow) as suggested by Geert

Questions:
x This patch might need to be split in two? (Introduce the new API, then use it)
x Convert other subsystems to show the value of this proposal?
x Maybe comment the API usage somewhere
---
 drivers/base/devres.c    | 15 ++++++
 drivers/clk/clk-devres.c | 99 ++++++++++++++--------------------------
 include/linux/device.h   |  3 ++
 3 files changed, 53 insertions(+), 64 deletions(-)

diff --git a/drivers/base/devres.c b/drivers/base/devres.c
index 0bbb328bd17f..b2603789755b 100644
--- a/drivers/base/devres.c
+++ b/drivers/base/devres.c
@@ -685,6 +685,21 @@ int devres_release_group(struct device *dev, void *id)
 }
 EXPORT_SYMBOL_GPL(devres_release_group);
 
+int devm_add(struct device *dev, dr_release_t func, void *arg, size_t size)
+{
+	void *data = devres_alloc(func, size, GFP_KERNEL);
+
+	if (!data) {
+		func(dev, arg);
+		return -ENOMEM;
+	}
+
+	memcpy(data, arg, size);
+	devres_add(dev, data);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(devm_add);
+
 /*
  * Custom devres actions allow inserting a simple function call
  * into the teadown sequence.
diff --git a/drivers/clk/clk-devres.c b/drivers/clk/clk-devres.c
index be160764911b..1da69d273855 100644
--- a/drivers/clk/clk-devres.c
+++ b/drivers/clk/clk-devres.c
@@ -4,26 +4,22 @@
 #include <linux/export.h>
 #include <linux/gfp.h>
 
-static void devm_clk_release(struct device *dev, void *res)
+static void my_clk_put(struct device *dev, void *res)
 {
 	clk_put(*(struct clk **)res);
 }
 
 struct clk *devm_clk_get(struct device *dev, const char *id)
 {
-	struct clk **ptr, *clk;
-
-	ptr = devres_alloc(devm_clk_release, sizeof(*ptr), GFP_KERNEL);
-	if (!ptr)
-		return ERR_PTR(-ENOMEM);
-
-	clk = clk_get(dev, id);
-	if (!IS_ERR(clk)) {
-		*ptr = clk;
-		devres_add(dev, ptr);
-	} else {
-		devres_free(ptr);
-	}
+	int ret;
+	struct clk *clk = clk_get(dev, id);
+
+	if (IS_ERR(clk))
+		return clk;
+
+	ret = devm_add(dev, my_clk_put, &clk, sizeof(clk));
+	if (ret)
+		return ERR_PTR(ret);
 
 	return clk;
 }
@@ -40,14 +36,14 @@ struct clk *devm_clk_get_optional(struct device *dev, const char *id)
 }
 EXPORT_SYMBOL(devm_clk_get_optional);
 
-struct clk_bulk_devres {
-	struct clk_bulk_data *clks;
+struct clk_bulk_args {
 	int num_clks;
+	struct clk_bulk_data *clks;
 };
 
-static void devm_clk_bulk_release(struct device *dev, void *res)
+static void my_clk_bulk_put(struct device *dev, void *res)
 {
-	struct clk_bulk_devres *devres = res;
+	struct clk_bulk_args *devres = res;
 
 	clk_bulk_put(devres->num_clks, devres->clks);
 }
@@ -55,25 +51,17 @@ static void devm_clk_bulk_release(struct device *dev, void *res)
 static int __devm_clk_bulk_get(struct device *dev, int num_clks,
 			       struct clk_bulk_data *clks, bool optional)
 {
-	struct clk_bulk_devres *devres;
 	int ret;
 
-	devres = devres_alloc(devm_clk_bulk_release,
-			      sizeof(*devres), GFP_KERNEL);
-	if (!devres)
-		return -ENOMEM;
-
 	if (optional)
 		ret = clk_bulk_get_optional(dev, num_clks, clks);
 	else
 		ret = clk_bulk_get(dev, num_clks, clks);
-	if (!ret) {
-		devres->clks = clks;
-		devres->num_clks = num_clks;
-		devres_add(dev, devres);
-	} else {
-		devres_free(devres);
-	}
+
+	if (ret)
+		return ret;
+
+	ret = devm_vadd(dev, my_clk_bulk_put, clk_bulk_args, num_clks, clks);
 
 	return ret;
 }
@@ -95,24 +83,15 @@ EXPORT_SYMBOL_GPL(devm_clk_bulk_get_optional);
 int __must_check devm_clk_bulk_get_all(struct device *dev,
 				       struct clk_bulk_data **clks)
 {
-	struct clk_bulk_devres *devres;
 	int ret;
+	int num_clks = clk_bulk_get_all(dev, clks);
 
-	devres = devres_alloc(devm_clk_bulk_release,
-			      sizeof(*devres), GFP_KERNEL);
-	if (!devres)
-		return -ENOMEM;
-
-	ret = clk_bulk_get_all(dev, &devres->clks);
-	if (ret > 0) {
-		*clks = devres->clks;
-		devres->num_clks = ret;
-		devres_add(dev, devres);
-	} else {
-		devres_free(devres);
-	}
+	if (num_clks <= 0)
+		return num_clks;
 
-	return ret;
+	ret = devm_vadd(dev, my_clk_bulk_put, clk_bulk_args, num_clks, *clks);
+
+	return ret ? : num_clks;
 }
 EXPORT_SYMBOL_GPL(devm_clk_bulk_get_all);
 
@@ -128,30 +107,22 @@ static int devm_clk_match(struct device *dev, void *res, void *data)
 
 void devm_clk_put(struct device *dev, struct clk *clk)
 {
-	int ret;
-
-	ret = devres_release(dev, devm_clk_release, devm_clk_match, clk);
-
-	WARN_ON(ret);
+	WARN_ON(devres_release(dev, my_clk_put, devm_clk_match, clk));
 }
 EXPORT_SYMBOL(devm_clk_put);
 
 struct clk *devm_get_clk_from_child(struct device *dev,
 				    struct device_node *np, const char *con_id)
 {
-	struct clk **ptr, *clk;
-
-	ptr = devres_alloc(devm_clk_release, sizeof(*ptr), GFP_KERNEL);
-	if (!ptr)
-		return ERR_PTR(-ENOMEM);
-
-	clk = of_clk_get_by_name(np, con_id);
-	if (!IS_ERR(clk)) {
-		*ptr = clk;
-		devres_add(dev, ptr);
-	} else {
-		devres_free(ptr);
-	}
+	int ret;
+	struct clk *clk = of_clk_get_by_name(np, con_id);
+
+	if (IS_ERR(clk))
+		return clk;
+
+	ret = devm_add(dev, my_clk_put, &clk, sizeof(clk));
+	if (ret)
+		return ERR_PTR(ret);
 
 	return clk;
 }
diff --git a/include/linux/device.h b/include/linux/device.h
index e226030c1df3..9f18582fc0f9 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -969,6 +969,9 @@ void __iomem *devm_of_iomap(struct device *dev,
 			    struct device_node *node, int index,
 			    resource_size_t *size);
 
+int devm_add(struct device *dev, dr_release_t func, void *arg, size_t size);
+#define devm_vadd(dev, func, type, args...) \
+	devm_add(dev, func, &(struct type){args}, sizeof(struct type))
 /* allows to add/remove a custom action to devres stack */
 int devm_add_action(struct device *dev, void (*action)(void *), void *data);
 void devm_remove_action(struct device *dev, void (*action)(void *), void *data);
-- 
2.17.1

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