From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: [PATCH 05/11] cgroup: clean up css_[try]get() and css_put() Date: Wed, 12 Jun 2013 21:04:52 -0700 Message-ID: <1371096298-24402-6-git-send-email-tj@kernel.org> References: <1371096298-24402-1-git-send-email-tj@kernel.org> Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=sender:from:to:cc:subject:date:message-id:x-mailer:in-reply-to :references; bh=JMshqTxdUnl6JJ1NdKXCk5NZL6YWC3B8oKJkbDGbGNk=; b=pLb3AlhDcV1JqS9UmFpJ0nVXr0oMa9do6kPQK/4M7HOUxTbAEJQMaV0h8dSBYLiJmI VUCpEWltIaUajowktILtvlddLZFKhL+FY7oGb+9Newpho/RHP1b3u+X6QYQ5WLlp+6sJ T0/dPabETkpKbFEmCMWDpanDetkWgSt2N/N628iRawonHo4fRn9DUWM6SLMHKe+3P//s izv3Ennifwcovw/lXfmWdtMhE2zQDpYK4ilaRJsi0Mkeb1hc7Rqg5nrDuXnmds0FtkI3 zsBEn6BzJByUP7AA7tvrKJugNIMbCqHk0bHq8Duwyj4XGGPjSG3mQV+AngVjLWA77sFY j3TQ== In-Reply-To: <1371096298-24402-1-git-send-email-tj@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: lizefan@huawei.com Cc: containers@lists.linux-foundation.org, cgroups@vger.kernel.org, koverstreet@google.com, linux-kernel@vger.kernel.org, cl@linux-foundation.org, Tejun Heo * __css_get() isn't used by anyone. Fold it into css_get(). * Add proper function comments to all css reference functions. This patch is purely cosmetic. v2: Typo fix as per Li. Signed-off-by: Tejun Heo Cc: Li Zefan --- include/linux/cgroup.h | 48 ++++++++++++++++++++++++------------------------ 1 file changed, 24 insertions(+), 24 deletions(-) diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 0e32855..a494636 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -94,33 +94,31 @@ enum { CSS_ONLINE = (1 << 1), /* between ->css_online() and ->css_offline() */ }; -/* Caller must verify that the css is not for root cgroup */ -static inline void __css_get(struct cgroup_subsys_state *css, int count) -{ - atomic_add(count, &css->refcnt); -} - -/* - * Call css_get() to hold a reference on the css; it can be used - * for a reference obtained via: - * - an existing ref-counted reference to the css - * - task->cgroups for a locked task +/** + * css_get - obtain a reference on the specified css + * @css: target css + * + * The caller must already have a reference. */ - static inline void css_get(struct cgroup_subsys_state *css) { /* We don't need to reference count the root state */ if (!(css->flags & CSS_ROOT)) - __css_get(css, 1); + atomic_inc(&css->refcnt); } -/* - * Call css_tryget() to take a reference on a css if your existing - * (known-valid) reference isn't already ref-counted. Returns false if - * the css has been destroyed. - */ - extern bool __css_tryget(struct cgroup_subsys_state *css); + +/** + * css_tryget - try to obtain a reference on the specified css + * @css: target css + * + * Obtain a reference on @css if it's alive. The caller naturally needs to + * ensure that @css is accessible but doesn't have to be holding a + * reference on it - IOW, RCU protected access is good enough for this + * function. Returns %true if a reference count was successfully obtained; + * %false otherwise. + */ static inline bool css_tryget(struct cgroup_subsys_state *css) { if (css->flags & CSS_ROOT) @@ -128,12 +126,14 @@ static inline bool css_tryget(struct cgroup_subsys_state *css) return __css_tryget(css); } -/* - * css_put() should be called to release a reference taken by - * css_get() or css_tryget() - */ - extern void __css_put(struct cgroup_subsys_state *css); + +/** + * css_put - put a css reference + * @css: target css + * + * Put a reference obtained via css_get() and css_tryget(). + */ static inline void css_put(struct cgroup_subsys_state *css) { if (!(css->flags & CSS_ROOT)) -- 1.8.2.1