[PATCH 0/2] mm:constify zpool/zs_pool char members

[PATCH 0/2] mm:constify zpool/zs_pool char members

[Sergey Senozhatsky]

Hi,
Two trivial patches to constify zs_pool and zpool ->name and ->type
members and functions' signatures that set/return them.

Sergey SENOZHATSKY (2):
  mm:zpool: constify struct zpool type
  mm:zsmalloc: constify struct zs_pool name

 include/linux/zpool.h    | 12 +++++++-----
 include/linux/zsmalloc.h |  2 +-
 mm/zbud.c                |  2 +-
 mm/zpool.c               | 12 ++++++------
 mm/zsmalloc.c            | 10 +++++-----
 5 files changed, 20 insertions(+), 18 deletions(-)

-- 
2.5.1

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[PATCH 1/2] mm:zpool: constify struct zpool type

[Sergey Senozhatsky]

From: Sergey SENOZHATSKY <sergey.senozhatsky@gmail.com>

Constify `struct zpool' ->type.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
---
 include/linux/zpool.h |  8 ++++----
 mm/zpool.c            | 10 +++++-----
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/include/linux/zpool.h b/include/linux/zpool.h
index 42f8ec9..2c136f4 100644
--- a/include/linux/zpool.h
+++ b/include/linux/zpool.h
@@ -36,12 +36,12 @@ enum zpool_mapmode {
 	ZPOOL_MM_DEFAULT = ZPOOL_MM_RW
 };
 
-bool zpool_has_pool(char *type);
+bool zpool_has_pool(const char *type);
 
-struct zpool *zpool_create_pool(char *type, char *name,
+struct zpool *zpool_create_pool(const char *type, char *name,
 			gfp_t gfp, const struct zpool_ops *ops);
 
-char *zpool_get_type(struct zpool *pool);
+const char *zpool_get_type(struct zpool *pool);
 
 void zpool_destroy_pool(struct zpool *pool);
 
@@ -78,7 +78,7 @@ u64 zpool_get_total_size(struct zpool *pool);
  * with zpool.
  */
 struct zpool_driver {
-	char *type;
+	const char *type;
 	struct module *owner;
 	atomic_t refcount;
 	struct list_head list;
diff --git a/mm/zpool.c b/mm/zpool.c
index 8f670d3..2889d0d 100644
--- a/mm/zpool.c
+++ b/mm/zpool.c
@@ -18,7 +18,7 @@
 #include <linux/zpool.h>
 
 struct zpool {
-	char *type;
+	const char *type;
 
 	struct zpool_driver *driver;
 	void *pool;
@@ -73,7 +73,7 @@ int zpool_unregister_driver(struct zpool_driver *driver)
 }
 EXPORT_SYMBOL(zpool_unregister_driver);
 
-static struct zpool_driver *zpool_get_driver(char *type)
+static struct zpool_driver *zpool_get_driver(const char *type)
 {
 	struct zpool_driver *driver;
 
@@ -115,7 +115,7 @@ static void zpool_put_driver(struct zpool_driver *driver)
  *
  * Returns: true if @type pool is available, false if not
  */
-bool zpool_has_pool(char *type)
+bool zpool_has_pool(const char *type)
 {
 	struct zpool_driver *driver = zpool_get_driver(type);
 
@@ -147,7 +147,7 @@ EXPORT_SYMBOL(zpool_has_pool);
  *
  * Returns: New zpool on success, NULL on failure.
  */
-struct zpool *zpool_create_pool(char *type, char *name, gfp_t gfp,
+struct zpool *zpool_create_pool(const char *type, char *name, gfp_t gfp,
 		const struct zpool_ops *ops)
 {
 	struct zpool_driver *driver;
@@ -228,7 +228,7 @@ void zpool_destroy_pool(struct zpool *zpool)
  *
  * Returns: The type of zpool.
  */
-char *zpool_get_type(struct zpool *zpool)
+const char *zpool_get_type(struct zpool *zpool)
 {
 	return zpool->type;
 }
-- 
2.5.1

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[PATCH 2/2] mm:zsmalloc: constify struct zs_pool name

[Sergey Senozhatsky]

From: Sergey SENOZHATSKY <sergey.senozhatsky@gmail.com>

Constify `struct zs_pool' ->name.

Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
---
 include/linux/zpool.h    |  6 ++++--
 include/linux/zsmalloc.h |  2 +-
 mm/zbud.c                |  2 +-
 mm/zpool.c               |  4 ++--
 mm/zsmalloc.c            | 10 +++++-----
 5 files changed, 13 insertions(+), 11 deletions(-)

diff --git a/include/linux/zpool.h b/include/linux/zpool.h
index 2c136f4..8edb451 100644
--- a/include/linux/zpool.h
+++ b/include/linux/zpool.h
@@ -38,7 +38,7 @@ enum zpool_mapmode {
 
 bool zpool_has_pool(const char *type);
 
-struct zpool *zpool_create_pool(const char *type, char *name,
+struct zpool *zpool_create_pool(const char *type, const char *name,
 			gfp_t gfp, const struct zpool_ops *ops);
 
 const char *zpool_get_type(struct zpool *pool);
@@ -83,7 +83,9 @@ struct zpool_driver {
 	atomic_t refcount;
 	struct list_head list;
 
-	void *(*create)(char *name, gfp_t gfp, const struct zpool_ops *ops,
+	void *(*create)(const char *name,
+			gfp_t gfp,
+			const struct zpool_ops *ops,
 			struct zpool *zpool);
 	void (*destroy)(void *pool);
 
diff --git a/include/linux/zsmalloc.h b/include/linux/zsmalloc.h
index 6398dfa..34eb160 100644
--- a/include/linux/zsmalloc.h
+++ b/include/linux/zsmalloc.h
@@ -41,7 +41,7 @@ struct zs_pool_stats {
 
 struct zs_pool;
 
-struct zs_pool *zs_create_pool(char *name, gfp_t flags);
+struct zs_pool *zs_create_pool(const char *name, gfp_t flags);
 void zs_destroy_pool(struct zs_pool *pool);
 
 unsigned long zs_malloc(struct zs_pool *pool, size_t size);
diff --git a/mm/zbud.c b/mm/zbud.c
index fa48bcdf..d8a181f 100644
--- a/mm/zbud.c
+++ b/mm/zbud.c
@@ -137,7 +137,7 @@ static const struct zbud_ops zbud_zpool_ops = {
 	.evict =	zbud_zpool_evict
 };
 
-static void *zbud_zpool_create(char *name, gfp_t gfp,
+static void *zbud_zpool_create(const char *name, gfp_t gfp,
 			       const struct zpool_ops *zpool_ops,
 			       struct zpool *zpool)
 {
diff --git a/mm/zpool.c b/mm/zpool.c
index 2889d0d..1247c28 100644
--- a/mm/zpool.c
+++ b/mm/zpool.c
@@ -147,8 +147,8 @@ EXPORT_SYMBOL(zpool_has_pool);
  *
  * Returns: New zpool on success, NULL on failure.
  */
-struct zpool *zpool_create_pool(const char *type, char *name, gfp_t gfp,
-		const struct zpool_ops *ops)
+struct zpool *zpool_create_pool(const char *type, const char *name,
+		gfp_t gfp, const struct zpool_ops *ops)
 {
 	struct zpool_driver *driver;
 	struct zpool *zpool;
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index f135b1b..8b8e0da 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -237,7 +237,7 @@ struct link_free {
 };
 
 struct zs_pool {
-	char *name;
+	const char *name;
 
 	struct size_class **size_class;
 	struct kmem_cache *handle_cachep;
@@ -311,7 +311,7 @@ static void record_obj(unsigned long handle, unsigned long obj)
 
 #ifdef CONFIG_ZPOOL
 
-static void *zs_zpool_create(char *name, gfp_t gfp,
+static void *zs_zpool_create(const char *name, gfp_t gfp,
 			     const struct zpool_ops *zpool_ops,
 			     struct zpool *zpool)
 {
@@ -548,7 +548,7 @@ static const struct file_operations zs_stat_size_ops = {
 	.release        = single_release,
 };
 
-static int zs_pool_stat_create(char *name, struct zs_pool *pool)
+static int zs_pool_stat_create(const char *name, struct zs_pool *pool)
 {
 	struct dentry *entry;
 
@@ -588,7 +588,7 @@ static void __exit zs_stat_exit(void)
 {
 }
 
-static inline int zs_pool_stat_create(char *name, struct zs_pool *pool)
+static inline int zs_pool_stat_create(const char *name, struct zs_pool *pool)
 {
 	return 0;
 }
@@ -1866,7 +1866,7 @@ static int zs_register_shrinker(struct zs_pool *pool)
  * On success, a pointer to the newly created pool is returned,
  * otherwise NULL.
  */
-struct zs_pool *zs_create_pool(char *name, gfp_t flags)
+struct zs_pool *zs_create_pool(const char *name, gfp_t flags)
 {
 	int i;
 	struct zs_pool *pool;
-- 
2.5.1

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Re: [PATCH 0/2] mm:constify zpool/zs_pool char members

[Sergey Senozhatsky]

On (09/10/15 20:48), Sergey Senozhatsky wrote:
> Two trivial patches to constify zs_pool and zpool ->name and ->type
> members and functions' signatures that set/return them.
> 

oh.. um.. somehow linux-next 20150910 contained zpool_has_pool()
function, which I can't find any more. I'll resend the patch set.

	-ss

> Sergey SENOZHATSKY (2):
>   mm:zpool: constify struct zpool type
>   mm:zsmalloc: constify struct zs_pool name
> 
>  include/linux/zpool.h    | 12 +++++++-----
>  include/linux/zsmalloc.h |  2 +-
>  mm/zbud.c                |  2 +-
>  mm/zpool.c               | 12 ++++++------
>  mm/zsmalloc.c            | 10 +++++-----
>  5 files changed, 20 insertions(+), 18 deletions(-)
> 
> -- 
> 2.5.1
> 

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Re: [PATCH 1/2] mm:zpool: constify struct zpool type

[Andrew Morton]

On Thu, 10 Sep 2015 20:48:37 +0900 Sergey Senozhatsky <sergey.senozhatsky@gmail.com> wrote:

> From: Sergey SENOZHATSKY <sergey.senozhatsky@gmail.com>
> 
> Constify `struct zpool' ->type.
> 

I think I prefer Dan's patch, which deletes stuff:

From: Dan Streetman <ddstreet@ieee.org>
Subject: zpool: remove redundant zpool->type string, const-ify zpool_get_type

Make the return type of zpool_get_type const; the string belongs to the
zpool driver and should not be modified.  Remove the redundant type field
in the struct zpool; it is private to zpool.c and isn't needed since
->driver->type can be used directly.  Add comments indicating strings must
be null-terminated.

Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Seth Jennings <sjennings@variantweb.net>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/zpool.h |    2 +-
 mm/zpool.c            |   14 ++++++++------
 2 files changed, 9 insertions(+), 7 deletions(-)

diff -puN include/linux/zpool.h~zpool-remove-redundant-zpool-type-string-const-ify-zpool_get_type include/linux/zpool.h
--- a/include/linux/zpool.h~zpool-remove-redundant-zpool-type-string-const-ify-zpool_get_type
+++ a/include/linux/zpool.h
@@ -41,7 +41,7 @@ bool zpool_has_pool(char *type);
 struct zpool *zpool_create_pool(char *type, char *name,
 			gfp_t gfp, const struct zpool_ops *ops);
 
-char *zpool_get_type(struct zpool *pool);
+const char *zpool_get_type(struct zpool *pool);
 
 void zpool_destroy_pool(struct zpool *pool);
 
diff -puN mm/zpool.c~zpool-remove-redundant-zpool-type-string-const-ify-zpool_get_type mm/zpool.c
--- a/mm/zpool.c~zpool-remove-redundant-zpool-type-string-const-ify-zpool_get_type
+++ a/mm/zpool.c
@@ -18,8 +18,6 @@
 #include <linux/zpool.h>
 
 struct zpool {
-	char *type;
-
 	struct zpool_driver *driver;
 	void *pool;
 	const struct zpool_ops *ops;
@@ -73,6 +71,7 @@ int zpool_unregister_driver(struct zpool
 }
 EXPORT_SYMBOL(zpool_unregister_driver);
 
+/* this assumes @type is null-terminated. */
 static struct zpool_driver *zpool_get_driver(char *type)
 {
 	struct zpool_driver *driver;
@@ -113,6 +112,8 @@ static void zpool_put_driver(struct zpoo
  * not be loaded, and calling @zpool_create_pool() with the pool type will
  * fail.
  *
+ * The @type string must be null-terminated.
+ *
  * Returns: true if @type pool is available, false if not
  */
 bool zpool_has_pool(char *type)
@@ -145,6 +146,8 @@ EXPORT_SYMBOL(zpool_has_pool);
  *
  * Implementations must guarantee this to be thread-safe.
  *
+ * The @type and @name strings must be null-terminated.
+ *
  * Returns: New zpool on success, NULL on failure.
  */
 struct zpool *zpool_create_pool(char *type, char *name, gfp_t gfp,
@@ -174,7 +177,6 @@ struct zpool *zpool_create_pool(char *ty
 		return NULL;
 	}
 
-	zpool->type = driver->type;
 	zpool->driver = driver;
 	zpool->pool = driver->create(name, gfp, ops, zpool);
 	zpool->ops = ops;
@@ -208,7 +210,7 @@ struct zpool *zpool_create_pool(char *ty
  */
 void zpool_destroy_pool(struct zpool *zpool)
 {
-	pr_debug("destroying pool type %s\n", zpool->type);
+	pr_debug("destroying pool type %s\n", zpool->driver->type);
 
 	spin_lock(&pools_lock);
 	list_del(&zpool->list);
@@ -228,9 +230,9 @@ void zpool_destroy_pool(struct zpool *zp
  *
  * Returns: The type of zpool.
  */
-char *zpool_get_type(struct zpool *zpool)
+const char *zpool_get_type(struct zpool *zpool)
 {
-	return zpool->type;
+	return zpool->driver->type;
 }
 
 /**
_

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Re: [PATCH 1/2] mm:zpool: constify struct zpool type

[Sergey Senozhatsky]

On (09/11/15 15:21), Andrew Morton wrote:
> > From: Sergey SENOZHATSKY <sergey.senozhatsky@gmail.com>
> > 
> > Constify `struct zpool' ->type.
> > 
> 
> I think I prefer Dan's patch, which deletes stuff:

Sure, agree. Somehow I overlooked it.

	-ss


> From: Dan Streetman <ddstreet@ieee.org>
> Subject: zpool: remove redundant zpool->type string, const-ify zpool_get_type
> 
> Make the return type of zpool_get_type const; the string belongs to the
> zpool driver and should not be modified.  Remove the redundant type field
> in the struct zpool; it is private to zpool.c and isn't needed since
> ->driver->type can be used directly.  Add comments indicating strings must
> be null-terminated.
> 
> Signed-off-by: Dan Streetman <ddstreet@ieee.org>
> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
> Cc: Seth Jennings <sjennings@variantweb.net>
> Cc: Minchan Kim <minchan@kernel.org>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
> 
>  include/linux/zpool.h |    2 +-
>  mm/zpool.c            |   14 ++++++++------
>  2 files changed, 9 insertions(+), 7 deletions(-)
> 
> diff -puN include/linux/zpool.h~zpool-remove-redundant-zpool-type-string-const-ify-zpool_get_type include/linux/zpool.h
> --- a/include/linux/zpool.h~zpool-remove-redundant-zpool-type-string-const-ify-zpool_get_type
> +++ a/include/linux/zpool.h
> @@ -41,7 +41,7 @@ bool zpool_has_pool(char *type);
>  struct zpool *zpool_create_pool(char *type, char *name,
>  			gfp_t gfp, const struct zpool_ops *ops);
>  
> -char *zpool_get_type(struct zpool *pool);
> +const char *zpool_get_type(struct zpool *pool);
>  
>  void zpool_destroy_pool(struct zpool *pool);
>  
> diff -puN mm/zpool.c~zpool-remove-redundant-zpool-type-string-const-ify-zpool_get_type mm/zpool.c
> --- a/mm/zpool.c~zpool-remove-redundant-zpool-type-string-const-ify-zpool_get_type
> +++ a/mm/zpool.c
> @@ -18,8 +18,6 @@
>  #include <linux/zpool.h>
>  
>  struct zpool {
> -	char *type;
> -
>  	struct zpool_driver *driver;
>  	void *pool;
>  	const struct zpool_ops *ops;
> @@ -73,6 +71,7 @@ int zpool_unregister_driver(struct zpool
>  }
>  EXPORT_SYMBOL(zpool_unregister_driver);
>  
> +/* this assumes @type is null-terminated. */
>  static struct zpool_driver *zpool_get_driver(char *type)
>  {
>  	struct zpool_driver *driver;
> @@ -113,6 +112,8 @@ static void zpool_put_driver(struct zpoo
>   * not be loaded, and calling @zpool_create_pool() with the pool type will
>   * fail.
>   *
> + * The @type string must be null-terminated.
> + *
>   * Returns: true if @type pool is available, false if not
>   */
>  bool zpool_has_pool(char *type)
> @@ -145,6 +146,8 @@ EXPORT_SYMBOL(zpool_has_pool);
>   *
>   * Implementations must guarantee this to be thread-safe.
>   *
> + * The @type and @name strings must be null-terminated.
> + *
>   * Returns: New zpool on success, NULL on failure.
>   */
>  struct zpool *zpool_create_pool(char *type, char *name, gfp_t gfp,
> @@ -174,7 +177,6 @@ struct zpool *zpool_create_pool(char *ty
>  		return NULL;
>  	}
>  
> -	zpool->type = driver->type;
>  	zpool->driver = driver;
>  	zpool->pool = driver->create(name, gfp, ops, zpool);
>  	zpool->ops = ops;
> @@ -208,7 +210,7 @@ struct zpool *zpool_create_pool(char *ty
>   */
>  void zpool_destroy_pool(struct zpool *zpool)
>  {
> -	pr_debug("destroying pool type %s\n", zpool->type);
> +	pr_debug("destroying pool type %s\n", zpool->driver->type);
>  
>  	spin_lock(&pools_lock);
>  	list_del(&zpool->list);
> @@ -228,9 +230,9 @@ void zpool_destroy_pool(struct zpool *zp
>   *
>   * Returns: The type of zpool.
>   */
> -char *zpool_get_type(struct zpool *zpool)
> +const char *zpool_get_type(struct zpool *zpool)
>  {
> -	return zpool->type;
> +	return zpool->driver->type;
>  }
>  
>  /**
> _
> 

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