linux-kernel - [PATCH v6] devres: combine function devm

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Date:   Mon, 29 Jan 2018 19:48:16 +0800
From:   Yisheng Xie <xieyisheng1@...wei.com>
To:     <gregkh@...uxfoundation.org>
CC:     <christophe.leroy@....fr>, <thomas.lendacky@....com>,
        <linux-kernel@...r.kernel.org>, <xieyisheng1@...wei.com>
Subject: [PATCH v6] devres: combine function devm_ioremap*

When I tried to use devm_ioremap function and review related
code, I found devm_ioremap_* almost have the similar realize
with each other, which can be combined.

In the former version, I have tried to kill ioremap_cache to
reduce the size of devres, which can not work for ioremap is
not the same as ioremap_nocache in some ARCHs likes ia64.
Therefore, as the suggestion of Christophe, I introduce a help
function __devm_ioremap, let devm_ioremap* inline and call
__devm_ioremap with different devm_ioremap_type.

After apply the patch, the size of devres.o can be reduce from
8216 Bytes to 8052 Bytes in my compile environment.

Suggested-by: Greg KH <gregkh@...uxfoundation.org>
Suggested-by: Christophe LEROY <christophe.leroy@....fr>
Signed-off-by: Yisheng Xie <xieyisheng1@...wei.com>
---
v2:
 - use MARCO for ioremap
v3:
 - kill dev_ioremap_nocache
v4:
 - combine function devm_ioremap*       - per Christophe
v5:
 - fix code style.                      - per Christophe
v6:
 - just put the cleanup in the devres.c - per Greg

 lib/devres.c | 78 +++++++++++++++++++++++++++++-------------------------------
 1 file changed, 38 insertions(+), 40 deletions(-)

diff --git a/lib/devres.c b/lib/devres.c
index 5f2aedd..5bec112 100644
--- a/lib/devres.c
+++ b/lib/devres.c
@@ -5,6 +5,12 @@
 #include <linux/gfp.h>
 #include <linux/export.h>
 
+enum devm_ioremap_type {
+	DEVM_IOREMAP = 0,
+	DEVM_IOREMAP_NC,
+	DEVM_IOREMAP_WC,
+};
+
 void devm_ioremap_release(struct device *dev, void *res)
 {
 	iounmap(*(void __iomem **)res);
@@ -15,24 +21,28 @@ static int devm_ioremap_match(struct device *dev, void *res, void *match_data)
 	return *(void **)res == match_data;
 }
 
-/**
- * devm_ioremap - Managed ioremap()
- * @dev: Generic device to remap IO address for
- * @offset: Resource address to map
- * @size: Size of map
- *
- * Managed ioremap().  Map is automatically unmapped on driver detach.
- */
-void __iomem *devm_ioremap(struct device *dev, resource_size_t offset,
-			   resource_size_t size)
+static void __iomem *__devm_ioremap(struct device *dev, resource_size_t offset,
+				    resource_size_t size,
+				    enum devm_ioremap_type type)
 {
-	void __iomem **ptr, *addr;
+	void __iomem **ptr, *addr = NULL;
 
 	ptr = devres_alloc(devm_ioremap_release, sizeof(*ptr), GFP_KERNEL);
 	if (!ptr)
 		return NULL;
 
-	addr = ioremap(offset, size);
+	switch (type) {
+	case DEVM_IOREMAP:
+		addr = ioremap(offset, size);
+		break;
+	case DEVM_IOREMAP_NC:
+		addr = ioremap_nocache(offset, size);
+		break;
+	case DEVM_IOREMAP_WC:
+		addr = ioremap_wc(offset, size);
+		break;
+	}
+
 	if (addr) {
 		*ptr = addr;
 		devres_add(dev, ptr);
@@ -41,6 +51,20 @@ void __iomem *devm_ioremap(struct device *dev, resource_size_t offset,
 
 	return addr;
 }
+
+/**
+ * devm_ioremap - Managed ioremap()
+ * @dev: Generic device to remap IO address for
+ * @offset: Resource address to map
+ * @size: Size of map
+ *
+ * Managed ioremap().  Map is automatically unmapped on driver detach.
+ */
+void __iomem *devm_ioremap(struct device *dev, resource_size_t offset,
+			   resource_size_t size)
+{
+	return __devm_ioremap(dev, offset, size, DEVM_IOREMAP);
+}
 EXPORT_SYMBOL(devm_ioremap);
 
 /**
@@ -55,20 +79,7 @@ void __iomem *devm_ioremap(struct device *dev, resource_size_t offset,
 void __iomem *devm_ioremap_nocache(struct device *dev, resource_size_t offset,
 				   resource_size_t size)
 {
-	void __iomem **ptr, *addr;
-
-	ptr = devres_alloc(devm_ioremap_release, sizeof(*ptr), GFP_KERNEL);
-	if (!ptr)
-		return NULL;
-
-	addr = ioremap_nocache(offset, size);
-	if (addr) {
-		*ptr = addr;
-		devres_add(dev, ptr);
-	} else
-		devres_free(ptr);
-
-	return addr;
+	return __devm_ioremap(dev, offset, size, DEVM_IOREMAP_NC);
 }
 EXPORT_SYMBOL(devm_ioremap_nocache);
 
@@ -83,20 +94,7 @@ void __iomem *devm_ioremap_nocache(struct device *dev, resource_size_t offset,
 void __iomem *devm_ioremap_wc(struct device *dev, resource_size_t offset,
 			      resource_size_t size)
 {
-	void __iomem **ptr, *addr;
-
-	ptr = devres_alloc(devm_ioremap_release, sizeof(*ptr), GFP_KERNEL);
-	if (!ptr)
-		return NULL;
-
-	addr = ioremap_wc(offset, size);
-	if (addr) {
-		*ptr = addr;
-		devres_add(dev, ptr);
-	} else
-		devres_free(ptr);
-
-	return addr;
+	return __devm_ioremap(dev, offset, size, DEVM_IOREMAP_WC);
 }
 EXPORT_SYMBOL(devm_ioremap_wc);
 
-- 
1.8.3.1