From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qk0-f179.google.com (mail-qk0-f179.google.com [209.85.220.179]) by kanga.kvack.org (Postfix) with ESMTP id 0B1726B0038 for ; Fri, 11 Sep 2015 18:22:11 -0400 (EDT) Received: by qkap81 with SMTP id p81so38106297qka.2 for ; Fri, 11 Sep 2015 15:22:10 -0700 (PDT) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org. [140.211.169.12]) by mx.google.com with ESMTPS id d19si2120048qhc.106.2015.09.11.15.22.10 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 11 Sep 2015 15:22:10 -0700 (PDT) Date: Fri, 11 Sep 2015 15:21:55 -0700 From: Andrew Morton Subject: Re: [PATCH 1/2] mm:zpool: constify struct zpool type Message-Id: <20150911152155.425f590018c01e689f2361e2@linux-foundation.org> In-Reply-To: <1441885718-32580-2-git-send-email-sergey.senozhatsky@gmail.com> References: <1441885718-32580-1-git-send-email-sergey.senozhatsky@gmail.com> <1441885718-32580-2-git-send-email-sergey.senozhatsky@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Sergey Senozhatsky Cc: Seth Jennings , Dan Streetman , Minchan Kim , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Sergey Senozhatsky On Thu, 10 Sep 2015 20:48:37 +0900 Sergey Senozhatsky wrote: > From: Sergey SENOZHATSKY > > Constify `struct zpool' ->type. > I think I prefer Dan's patch, which deletes stuff: From: Dan Streetman 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 Cc: Sergey Senozhatsky Cc: Seth Jennings Cc: Minchan Kim Signed-off-by: Andrew Morton --- 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 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; } /** _ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org