[PATCH v2 0/4] devres: provide and use devm_kstrdup_const()

[PATCH v2 0/4] devres: provide and use devm_kstrdup_const()

[Bartosz Golaszewski]

This series implements devm_kstrdup_const() together with some
prerequisite changes and uses it in pmc-atom driver.

v1 -> v2:
- fixed the changelog in the patch implementing devm_kstrdup_const()
- fixed the kernel doc
- moved is_kernel_rodata() to asm-generic/sections.h
- fixed constness

Bartosz Golaszewski (4):
  devres: constify p in devm_kfree()
  mm: move is_kernel_rodata() to asm-generic/sections.h
  devres: provide devm_kstrdup_const()
  clk: pmc-atom: use devm_kstrdup_const()

 drivers/base/devres.c          | 43 ++++++++++++++++++++++++++++++++--
 drivers/clk/x86/clk-pmc-atom.c | 19 ++++-----------
 include/asm-generic/sections.h | 14 +++++++++++
 include/linux/device.h         |  5 +++-
 mm/util.c                      |  7 ------
 5 files changed, 63 insertions(+), 25 deletions(-)

-- 
2.18.0

[PATCH v2 1/4] devres: constify p in devm_kfree()

[Bartosz Golaszewski]

Make devm_kfree() signature uniform with that of kfree(). To avoid
compiler warnings: cast p to (void *) when calling devres_destroy().

Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
---
 drivers/base/devres.c  | 5 +++--
 include/linux/device.h | 2 +-
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/base/devres.c b/drivers/base/devres.c
index f98a097e73f2..438c91a43508 100644
--- a/drivers/base/devres.c
+++ b/drivers/base/devres.c
@@ -885,11 +885,12 @@ EXPORT_SYMBOL_GPL(devm_kasprintf);
  *
  * Free memory allocated with devm_kmalloc().
  */
-void devm_kfree(struct device *dev, void *p)
+void devm_kfree(struct device *dev, const void *p)
 {
 	int rc;
 
-	rc = devres_destroy(dev, devm_kmalloc_release, devm_kmalloc_match, p);
+	rc = devres_destroy(dev, devm_kmalloc_release,
+			    devm_kmalloc_match, (void *)p);
 	WARN_ON(rc);
 }
 EXPORT_SYMBOL_GPL(devm_kfree);
diff --git a/include/linux/device.h b/include/linux/device.h
index 8f882549edee..33f7cb271fbb 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -692,7 +692,7 @@ static inline void *devm_kcalloc(struct device *dev,
 {
 	return devm_kmalloc_array(dev, n, size, flags | __GFP_ZERO);
 }
-extern void devm_kfree(struct device *dev, void *p);
+extern void devm_kfree(struct device *dev, const void *p);
 extern char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp) __malloc;
 extern void *devm_kmemdup(struct device *dev, const void *src, size_t len,
 			  gfp_t gfp);
-- 
2.18.0

[PATCH v2 2/4] mm: move is_kernel_rodata() to asm-generic/sections.h

[Bartosz Golaszewski]

Export this routine so that we can use it later in devm_kstrdup_const()
and devm_kfree_const().

Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
---
 include/asm-generic/sections.h | 14 ++++++++++++++
 mm/util.c                      |  7 -------
 2 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h
index 849cd8eb5ca0..d79abca81a52 100644
--- a/include/asm-generic/sections.h
+++ b/include/asm-generic/sections.h
@@ -141,4 +141,18 @@ static inline bool init_section_intersects(void *virt, size_t size)
 	return memory_intersects(__init_begin, __init_end, virt, size);
 }
 
+/**
+ * is_kernel_rodata - checks if the pointer address is located in the
+ *                    .rodata section
+ *
+ * @addr: address to check
+ *
+ * Returns: true if the address is located in .rodata, false otherwise.
+ */
+static inline bool is_kernel_rodata(unsigned long addr)
+{
+	return addr >= (unsigned long)__start_rodata &&
+	       addr < (unsigned long)__end_rodata;
+}
+
 #endif /* _ASM_GENERIC_SECTIONS_H_ */
diff --git a/mm/util.c b/mm/util.c
index d2890a407332..41e9892a50ce 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -15,17 +15,10 @@
 #include <linux/vmalloc.h>
 #include <linux/userfaultfd_k.h>
 
-#include <asm/sections.h>
 #include <linux/uaccess.h>
 
 #include "internal.h"
 
-static inline int is_kernel_rodata(unsigned long addr)
-{
-	return addr >= (unsigned long)__start_rodata &&
-		addr < (unsigned long)__end_rodata;
-}
-
 /**
  * kfree_const - conditionally free memory
  * @x: pointer to the memory
-- 
2.18.0

[PATCH v2 3/4] devres: provide devm_kstrdup_const()

[Bartosz Golaszewski]

Provide a resource managed version of kstrdup_const(). This variant
internally calls devm_kstrdup() on pointers that are outside of
.rodata section and returns the string as is otherwise.

Also provide a corresponding version of devm_kfree().

Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
---
 drivers/base/devres.c  | 38 ++++++++++++++++++++++++++++++++++++++
 include/linux/device.h |  3 +++
 2 files changed, 41 insertions(+)

diff --git a/drivers/base/devres.c b/drivers/base/devres.c
index 438c91a43508..48185d57bc5b 100644
--- a/drivers/base/devres.c
+++ b/drivers/base/devres.c
@@ -11,6 +11,8 @@
 #include <linux/slab.h>
 #include <linux/percpu.h>
 
+#include <asm/sections.h>
+
 #include "base.h"
 
 struct devres_node {
@@ -822,6 +824,28 @@ char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp)
 }
 EXPORT_SYMBOL_GPL(devm_kstrdup);
 
+/**
+ * devm_kstrdup_const - resource managed conditional string duplication
+ * @dev: device for which to duplicate the string
+ * @s: the string to duplicate
+ * @gfp: the GFP mask used in the kmalloc() call when allocating memory
+ *
+ * Strings allocated by devm_kstrdup_const will be automatically freed when
+ * the associated device is detached.
+ *
+ * RETURNS:
+ * Source string if it is in .rodata section otherwise it falls back to
+ * devm_kstrdup.
+ */
+const char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t gfp)
+{
+	if (is_kernel_rodata((unsigned long)s))
+		return s;
+
+	return devm_kstrdup(dev, s, gfp);
+}
+EXPORT_SYMBOL(devm_kstrdup_const);
+
 /**
  * devm_kvasprintf - Allocate resource managed space and format a string
  *		     into that.
@@ -895,6 +919,20 @@ void devm_kfree(struct device *dev, const void *p)
 }
 EXPORT_SYMBOL_GPL(devm_kfree);
 
+/**
+ * devm_kfree_const - Resource managed conditional kfree
+ * @dev: device this memory belongs to
+ * @p: memory to free
+ *
+ * Function calls devm_kfree only if @p is not in .rodata section.
+ */
+void devm_kfree_const(struct device *dev, const void *p)
+{
+	if (!is_kernel_rodata((unsigned long)p))
+		devm_kfree(dev, p);
+}
+EXPORT_SYMBOL(devm_kfree_const);
+
 /**
  * devm_kmemdup - Resource-managed kmemdup
  * @dev: Device this memory belongs to
diff --git a/include/linux/device.h b/include/linux/device.h
index 33f7cb271fbb..79ccc6eb0975 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -693,7 +693,10 @@ static inline void *devm_kcalloc(struct device *dev,
 	return devm_kmalloc_array(dev, n, size, flags | __GFP_ZERO);
 }
 extern void devm_kfree(struct device *dev, const void *p);
+extern void devm_kfree_const(struct device *dev, const void *p);
 extern char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp) __malloc;
+extern const char *devm_kstrdup_const(struct device *dev,
+				      const char *s, gfp_t gfp);
 extern void *devm_kmemdup(struct device *dev, const void *src, size_t len,
 			  gfp_t gfp);
 
-- 
2.18.0

[PATCH v2 4/4] clk: pmc-atom: use devm_kstrdup_const()

[Bartosz Golaszewski]

Use devm_kstrdup_const() in the pmc-atom driver. This mostly serves as
an example of how to use this new routine to shrink driver code.

While we're at it: replace a call to kcalloc() with devm_kcalloc().

Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
---
 drivers/clk/x86/clk-pmc-atom.c | 19 ++++---------------
 1 file changed, 4 insertions(+), 15 deletions(-)

diff --git a/drivers/clk/x86/clk-pmc-atom.c b/drivers/clk/x86/clk-pmc-atom.c
index 08ef69945ffb..daa2192e6568 100644
--- a/drivers/clk/x86/clk-pmc-atom.c
+++ b/drivers/clk/x86/clk-pmc-atom.c
@@ -253,14 +253,6 @@ static void plt_clk_unregister_fixed_rate_loop(struct clk_plt_data *data,
 		plt_clk_unregister_fixed_rate(data->parents[i]);
 }
 
-static void plt_clk_free_parent_names_loop(const char **parent_names,
-					   unsigned int i)
-{
-	while (i--)
-		kfree_const(parent_names[i]);
-	kfree(parent_names);
-}
-
 static void plt_clk_unregister_loop(struct clk_plt_data *data,
 				    unsigned int i)
 {
@@ -286,8 +278,8 @@ static const char **plt_clk_register_parents(struct platform_device *pdev,
 	if (!data->parents)
 		return ERR_PTR(-ENOMEM);
 
-	parent_names = kcalloc(nparents, sizeof(*parent_names),
-			       GFP_KERNEL);
+	parent_names = devm_kcalloc(&pdev->dev, nparents,
+				    sizeof(*parent_names), GFP_KERNEL);
 	if (!parent_names)
 		return ERR_PTR(-ENOMEM);
 
@@ -300,7 +292,8 @@ static const char **plt_clk_register_parents(struct platform_device *pdev,
 			err = PTR_ERR(data->parents[i]);
 			goto err_unreg;
 		}
-		parent_names[i] = kstrdup_const(clks[i].name, GFP_KERNEL);
+		parent_names[i] = devm_kstrdup_const(&pdev->dev,
+						     clks[i].name, GFP_KERNEL);
 	}
 
 	data->nparents = nparents;
@@ -308,7 +301,6 @@ static const char **plt_clk_register_parents(struct platform_device *pdev,
 
 err_unreg:
 	plt_clk_unregister_fixed_rate_loop(data, i);
-	plt_clk_free_parent_names_loop(parent_names, i);
 	return ERR_PTR(err);
 }
 
@@ -351,15 +343,12 @@ static int plt_clk_probe(struct platform_device *pdev)
 		goto err_unreg_clk_plt;
 	}
 
-	plt_clk_free_parent_names_loop(parent_names, data->nparents);
-
 	platform_set_drvdata(pdev, data);
 	return 0;
 
 err_unreg_clk_plt:
 	plt_clk_unregister_loop(data, i);
 	plt_clk_unregister_parents(data);
-	plt_clk_free_parent_names_loop(parent_names, data->nparents);
 	return err;
 }
 
-- 
2.18.0

Re: [PATCH v2 4/4] clk: pmc-atom: use devm_kstrdup_const()

[Stephen Boyd]

Quoting Bartosz Golaszewski (2018-08-28 02:33:32)
> Use devm_kstrdup_const() in the pmc-atom driver. This mostly serves as
> an example of how to use this new routine to shrink driver code.
> 
> While we're at it: replace a call to kcalloc() with devm_kcalloc().
> 
> Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
> ---

Reviewed-by: Stephen Boyd <sboyd@kernel.org>

If you want this example to be merged through the clk tree please resend
after the other patches merge.

Re: [PATCH v2 4/4] clk: pmc-atom: use devm_kstrdup_const()

[Stephen Boyd]

Quoting Bartosz Golaszewski (2018-08-28 02:33:32)
> Use devm_kstrdup_const() in the pmc-atom driver. This mostly serves as
> an example of how to use this new routine to shrink driver code.
> =

> While we're at it: replace a call to kcalloc() with devm_kcalloc().
> =

> Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
> ---

Reviewed-by: Stephen Boyd <sboyd@kernel.org>

If you want this example to be merged through the clk tree please resend
after the other patches merge.

Re: [PATCH v2 4/4] clk: pmc-atom: use devm_kstrdup_const()

[Stephen Boyd]

Quoting Bartosz Golaszewski (2018-08-28 02:33:32)
> Use devm_kstrdup_const() in the pmc-atom driver. This mostly serves as
> an example of how to use this new routine to shrink driver code.
> 
> While we're at it: replace a call to kcalloc() with devm_kcalloc().
> 
> Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
> ---

Reviewed-by: Stephen Boyd <sboyd@kernel.org>

If you want this example to be merged through the clk tree please resend
after the other patches merge.

Re: [PATCH v2 0/4] devres: provide and use devm_kstrdup_const()

[Bartosz Golaszewski]

2018-08-28 11:33 GMT+02:00 Bartosz Golaszewski <brgl@bgdev.pl>:
> This series implements devm_kstrdup_const() together with some
> prerequisite changes and uses it in pmc-atom driver.
>
> v1 -> v2:
> - fixed the changelog in the patch implementing devm_kstrdup_const()
> - fixed the kernel doc
> - moved is_kernel_rodata() to asm-generic/sections.h
> - fixed constness
>
> Bartosz Golaszewski (4):
>   devres: constify p in devm_kfree()
>   mm: move is_kernel_rodata() to asm-generic/sections.h
>   devres: provide devm_kstrdup_const()
>   clk: pmc-atom: use devm_kstrdup_const()
>
>  drivers/base/devres.c          | 43 ++++++++++++++++++++++++++++++++--
>  drivers/clk/x86/clk-pmc-atom.c | 19 ++++-----------
>  include/asm-generic/sections.h | 14 +++++++++++
>  include/linux/device.h         |  5 +++-
>  mm/util.c                      |  7 ------
>  5 files changed, 63 insertions(+), 25 deletions(-)
>
> --
> 2.18.0
>

If there are no objections - can this be picked up for 4.20?

Thanks,
Bartosz

Re: [PATCH v2 1/4] devres: constify p in devm_kfree()

[Bjorn Andersson]

On Tue 28 Aug 02:33 PDT 2018, Bartosz Golaszewski wrote:

> Make devm_kfree() signature uniform with that of kfree(). To avoid
> compiler warnings: cast p to (void *) when calling devres_destroy().
> 

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Regards,
Bjorn

> Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
> ---
>  drivers/base/devres.c  | 5 +++--
>  include/linux/device.h | 2 +-
>  2 files changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/base/devres.c b/drivers/base/devres.c
> index f98a097e73f2..438c91a43508 100644
> --- a/drivers/base/devres.c
> +++ b/drivers/base/devres.c
> @@ -885,11 +885,12 @@ EXPORT_SYMBOL_GPL(devm_kasprintf);
>   *
>   * Free memory allocated with devm_kmalloc().
>   */
> -void devm_kfree(struct device *dev, void *p)
> +void devm_kfree(struct device *dev, const void *p)
>  {
>  	int rc;
>  
> -	rc = devres_destroy(dev, devm_kmalloc_release, devm_kmalloc_match, p);
> +	rc = devres_destroy(dev, devm_kmalloc_release,
> +			    devm_kmalloc_match, (void *)p);
>  	WARN_ON(rc);
>  }
>  EXPORT_SYMBOL_GPL(devm_kfree);
> diff --git a/include/linux/device.h b/include/linux/device.h
> index 8f882549edee..33f7cb271fbb 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -692,7 +692,7 @@ static inline void *devm_kcalloc(struct device *dev,
>  {
>  	return devm_kmalloc_array(dev, n, size, flags | __GFP_ZERO);
>  }
> -extern void devm_kfree(struct device *dev, void *p);
> +extern void devm_kfree(struct device *dev, const void *p);
>  extern char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp) __malloc;
>  extern void *devm_kmemdup(struct device *dev, const void *src, size_t len,
>  			  gfp_t gfp);
> -- 
> 2.18.0
> 

Re: [PATCH v2 2/4] mm: move is_kernel_rodata() to asm-generic/sections.h

[Bjorn Andersson]

On Tue 28 Aug 02:33 PDT 2018, Bartosz Golaszewski wrote:

> Export this routine so that we can use it later in devm_kstrdup_const()
> and devm_kfree_const().
> 

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Regards,
Bjorn

> Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
> ---
>  include/asm-generic/sections.h | 14 ++++++++++++++
>  mm/util.c                      |  7 -------
>  2 files changed, 14 insertions(+), 7 deletions(-)
> 
> diff --git a/include/asm-generic/sections.h b/include/asm-generic/sections.h
> index 849cd8eb5ca0..d79abca81a52 100644
> --- a/include/asm-generic/sections.h
> +++ b/include/asm-generic/sections.h
> @@ -141,4 +141,18 @@ static inline bool init_section_intersects(void *virt, size_t size)
>  	return memory_intersects(__init_begin, __init_end, virt, size);
>  }
>  
> +/**
> + * is_kernel_rodata - checks if the pointer address is located in the
> + *                    .rodata section
> + *
> + * @addr: address to check
> + *
> + * Returns: true if the address is located in .rodata, false otherwise.
> + */
> +static inline bool is_kernel_rodata(unsigned long addr)
> +{
> +	return addr >= (unsigned long)__start_rodata &&
> +	       addr < (unsigned long)__end_rodata;
> +}
> +
>  #endif /* _ASM_GENERIC_SECTIONS_H_ */
> diff --git a/mm/util.c b/mm/util.c
> index d2890a407332..41e9892a50ce 100644
> --- a/mm/util.c
> +++ b/mm/util.c
> @@ -15,17 +15,10 @@
>  #include <linux/vmalloc.h>
>  #include <linux/userfaultfd_k.h>
>  
> -#include <asm/sections.h>
>  #include <linux/uaccess.h>
>  
>  #include "internal.h"
>  
> -static inline int is_kernel_rodata(unsigned long addr)
> -{
> -	return addr >= (unsigned long)__start_rodata &&
> -		addr < (unsigned long)__end_rodata;
> -}
> -
>  /**
>   * kfree_const - conditionally free memory
>   * @x: pointer to the memory
> -- 
> 2.18.0
> 

Re: [PATCH v2 3/4] devres: provide devm_kstrdup_const()

[Bjorn Andersson]

On Tue 28 Aug 02:33 PDT 2018, Bartosz Golaszewski wrote:

> Provide a resource managed version of kstrdup_const(). This variant
> internally calls devm_kstrdup() on pointers that are outside of
> .rodata section and returns the string as is otherwise.
> 
> Also provide a corresponding version of devm_kfree().
> 
> Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Regards,
Bjorn

> ---
>  drivers/base/devres.c  | 38 ++++++++++++++++++++++++++++++++++++++
>  include/linux/device.h |  3 +++
>  2 files changed, 41 insertions(+)
> 
> diff --git a/drivers/base/devres.c b/drivers/base/devres.c
> index 438c91a43508..48185d57bc5b 100644
> --- a/drivers/base/devres.c
> +++ b/drivers/base/devres.c
> @@ -11,6 +11,8 @@
>  #include <linux/slab.h>
>  #include <linux/percpu.h>
>  
> +#include <asm/sections.h>
> +
>  #include "base.h"
>  
>  struct devres_node {
> @@ -822,6 +824,28 @@ char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp)
>  }
>  EXPORT_SYMBOL_GPL(devm_kstrdup);
>  
> +/**
> + * devm_kstrdup_const - resource managed conditional string duplication
> + * @dev: device for which to duplicate the string
> + * @s: the string to duplicate
> + * @gfp: the GFP mask used in the kmalloc() call when allocating memory
> + *
> + * Strings allocated by devm_kstrdup_const will be automatically freed when
> + * the associated device is detached.
> + *
> + * RETURNS:
> + * Source string if it is in .rodata section otherwise it falls back to
> + * devm_kstrdup.
> + */
> +const char *devm_kstrdup_const(struct device *dev, const char *s, gfp_t gfp)
> +{
> +	if (is_kernel_rodata((unsigned long)s))
> +		return s;
> +
> +	return devm_kstrdup(dev, s, gfp);
> +}
> +EXPORT_SYMBOL(devm_kstrdup_const);
> +
>  /**
>   * devm_kvasprintf - Allocate resource managed space and format a string
>   *		     into that.
> @@ -895,6 +919,20 @@ void devm_kfree(struct device *dev, const void *p)
>  }
>  EXPORT_SYMBOL_GPL(devm_kfree);
>  
> +/**
> + * devm_kfree_const - Resource managed conditional kfree
> + * @dev: device this memory belongs to
> + * @p: memory to free
> + *
> + * Function calls devm_kfree only if @p is not in .rodata section.
> + */
> +void devm_kfree_const(struct device *dev, const void *p)
> +{
> +	if (!is_kernel_rodata((unsigned long)p))
> +		devm_kfree(dev, p);
> +}
> +EXPORT_SYMBOL(devm_kfree_const);
> +
>  /**
>   * devm_kmemdup - Resource-managed kmemdup
>   * @dev: Device this memory belongs to
> diff --git a/include/linux/device.h b/include/linux/device.h
> index 33f7cb271fbb..79ccc6eb0975 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -693,7 +693,10 @@ static inline void *devm_kcalloc(struct device *dev,
>  	return devm_kmalloc_array(dev, n, size, flags | __GFP_ZERO);
>  }
>  extern void devm_kfree(struct device *dev, const void *p);
> +extern void devm_kfree_const(struct device *dev, const void *p);
>  extern char *devm_kstrdup(struct device *dev, const char *s, gfp_t gfp) __malloc;
> +extern const char *devm_kstrdup_const(struct device *dev,
> +				      const char *s, gfp_t gfp);
>  extern void *devm_kmemdup(struct device *dev, const void *src, size_t len,
>  			  gfp_t gfp);
>  
> -- 
> 2.18.0
> 

Re: [PATCH v2 4/4] clk: pmc-atom: use devm_kstrdup_const()

[Bjorn Andersson]

On Tue 28 Aug 02:33 PDT 2018, Bartosz Golaszewski wrote:

> Use devm_kstrdup_const() in the pmc-atom driver. This mostly serves as
> an example of how to use this new routine to shrink driver code.
> 
> While we're at it: replace a call to kcalloc() with devm_kcalloc().
> 
> Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>

Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>

Regards,
Bjorn

> ---
>  drivers/clk/x86/clk-pmc-atom.c | 19 ++++---------------
>  1 file changed, 4 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/clk/x86/clk-pmc-atom.c b/drivers/clk/x86/clk-pmc-atom.c
> index 08ef69945ffb..daa2192e6568 100644
> --- a/drivers/clk/x86/clk-pmc-atom.c
> +++ b/drivers/clk/x86/clk-pmc-atom.c
> @@ -253,14 +253,6 @@ static void plt_clk_unregister_fixed_rate_loop(struct clk_plt_data *data,
>  		plt_clk_unregister_fixed_rate(data->parents[i]);
>  }
>  
> -static void plt_clk_free_parent_names_loop(const char **parent_names,
> -					   unsigned int i)
> -{
> -	while (i--)
> -		kfree_const(parent_names[i]);
> -	kfree(parent_names);
> -}
> -
>  static void plt_clk_unregister_loop(struct clk_plt_data *data,
>  				    unsigned int i)
>  {
> @@ -286,8 +278,8 @@ static const char **plt_clk_register_parents(struct platform_device *pdev,
>  	if (!data->parents)
>  		return ERR_PTR(-ENOMEM);
>  
> -	parent_names = kcalloc(nparents, sizeof(*parent_names),
> -			       GFP_KERNEL);
> +	parent_names = devm_kcalloc(&pdev->dev, nparents,
> +				    sizeof(*parent_names), GFP_KERNEL);
>  	if (!parent_names)
>  		return ERR_PTR(-ENOMEM);
>  
> @@ -300,7 +292,8 @@ static const char **plt_clk_register_parents(struct platform_device *pdev,
>  			err = PTR_ERR(data->parents[i]);
>  			goto err_unreg;
>  		}
> -		parent_names[i] = kstrdup_const(clks[i].name, GFP_KERNEL);
> +		parent_names[i] = devm_kstrdup_const(&pdev->dev,
> +						     clks[i].name, GFP_KERNEL);
>  	}
>  
>  	data->nparents = nparents;
> @@ -308,7 +301,6 @@ static const char **plt_clk_register_parents(struct platform_device *pdev,
>  
>  err_unreg:
>  	plt_clk_unregister_fixed_rate_loop(data, i);
> -	plt_clk_free_parent_names_loop(parent_names, i);
>  	return ERR_PTR(err);
>  }
>  
> @@ -351,15 +343,12 @@ static int plt_clk_probe(struct platform_device *pdev)
>  		goto err_unreg_clk_plt;
>  	}
>  
> -	plt_clk_free_parent_names_loop(parent_names, data->nparents);
> -
>  	platform_set_drvdata(pdev, data);
>  	return 0;
>  
>  err_unreg_clk_plt:
>  	plt_clk_unregister_loop(data, i);
>  	plt_clk_unregister_parents(data);
> -	plt_clk_free_parent_names_loop(parent_names, data->nparents);
>  	return err;
>  }
>  
> -- 
> 2.18.0
> 

Re: [PATCH v2 0/4] devres: provide and use devm_kstrdup_const()

[Stephen Boyd]

Quoting Bartosz Golaszewski (2018-09-20 05:59:54)
> 2018-08-28 11:33 GMT+02:00 Bartosz Golaszewski <brgl@bgdev.pl>:
> > This series implements devm_kstrdup_const() together with some
> > prerequisite changes and uses it in pmc-atom driver.
> >
> > v1 -> v2:
> > - fixed the changelog in the patch implementing devm_kstrdup_const()
> > - fixed the kernel doc
> > - moved is_kernel_rodata() to asm-generic/sections.h
> > - fixed constness
> >
> > Bartosz Golaszewski (4):
> >   devres: constify p in devm_kfree()
> >   mm: move is_kernel_rodata() to asm-generic/sections.h
> >   devres: provide devm_kstrdup_const()
> >   clk: pmc-atom: use devm_kstrdup_const()
> >
> >  drivers/base/devres.c          | 43 ++++++++++++++++++++++++++++++++--
> >  drivers/clk/x86/clk-pmc-atom.c | 19 ++++-----------
> >  include/asm-generic/sections.h | 14 +++++++++++
> >  include/linux/device.h         |  5 +++-
> >  mm/util.c                      |  7 ------
> >  5 files changed, 63 insertions(+), 25 deletions(-)
> >
> > --
> > 2.18.0
> >
> 
> If there are no objections - can this be picked up for 4.20?
> 

There are so many people on To: line who do you want to pick this up?
Maybe you can send a pull request to Greg directly.