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Tue, 13 Jun 2023 10:55:23 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id A79843002F1; Tue, 13 Jun 2023 12:55:22 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 8D05424556032; Tue, 13 Jun 2023 12:55:22 +0200 (CEST) Date: Tue, 13 Jun 2023 12:55:22 +0200 From: Peter Zijlstra To: torvalds@linux-foundation.org, keescook@chromium.org, gregkh@linuxfoundation.org, pbonzini@redhat.com Cc: masahiroy@kernel.org, nathan@kernel.org, ndesaulniers@google.com, nicolas@fjasle.eu, catalin.marinas@arm.com, will@kernel.org, vkoul@kernel.org, trix@redhat.com, ojeda@kernel.org, mingo@redhat.com, longman@redhat.com, boqun.feng@gmail.com, dennis@kernel.org, tj@kernel.org, cl@linux.com, acme@kernel.org, mark.rutland@arm.com, alexander.shishkin@linux.intel.com, jolsa@kernel.org, namhyung@kernel.org, irogers@google.com, adrian.hunter@intel.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, bristot@redhat.com, vschneid@redhat.com, paulmck@kernel.org, frederic@kernel.org, quic_neeraju@quicinc.com, joel@joelfernandes.org, josh@joshtriplett.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, rientjes@google.com, vbabka@suse.cz, roman.gushchin@linux.dev, 42.hyeyoo@gmail.com, apw@canonical.com, joe@perches.com, dwaipayanray1@gmail.com, lukas.bulwahn@gmail.com, john.johansen@canonical.com, paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com, linux-kbuild@vger.kernel.org, linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org, llvm@lists.linux.dev, linux-perf-users@vger.kernel.org, rcu@vger.kernel.org, linux-security-module@vger.kernel.org, tglx@linutronix.de, ravi.bangoria@amd.com, error27@gmail.com, luc.vanoostenryck@gmail.com Subject: Re: [PATCH v3 03/57] locking: Introduce __cleanup() based infrastructure Message-ID: <20230613105522.GU4253@hirez.programming.kicks-ass.net> References: <20230612090713.652690195@infradead.org> <20230612093537.614161713@infradead.org> Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230612093537.614161713@infradead.org> On Mon, Jun 12, 2023 at 11:07:16AM +0200, Peter Zijlstra wrote: > --- /dev/null > +++ b/include/linux/cleanup.h > @@ -0,0 +1,167 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +#ifndef __LINUX_GUARDS_H > +#define __LINUX_GUARDS_H > + > +#include > + > +/* > + * DEFINE_FREE(name, type, free): > + * simple helper macro that defines the required wrapper for a __free() > + * based cleanup function. @free is an expression using '_T' to access > + * the variable. > + * > + * __free(name): > + * variable attribute to add a scoped based cleanup to the variable. > + * no_free_ptr(var): like a non-atomic xchg(var, NULL), such that the cleanup function will be inhibited -- provided it sanely deals with a NULL value. > + * return_ptr(p): > + * returns p while inhibiting the __free(). > + * > + * Ex. > + * > + * DEFINE_FREE(kfree, void *, if (_T) kfree(_T)) > + * > + * struct obj *p = kmalloc(...); That should obviously have been: struct obj *p __free(kfree) = kmalloc(...); > + * if (!p) > + * return NULL; > + * > + * if (!init_obj(p)) > + * return NULL; > + * > + * return_ptr(p); > + */ > + > +#define DEFINE_FREE(name, type, free) \ > + static inline void __free_##name(void *p) { type _T = *(type *)p; free; } > + > +#define __free(name) __cleanup(__free_##name) > + > +#define no_free_ptr(p) \ > + ({ __auto_type __ptr = (p); (p) = NULL; __ptr; }) > + > +#define return_ptr(p) return no_free_ptr(p)