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[149.6.153.186]) by smtp.googlemail.com with ESMTPSA id v18-20020a5d43d2000000b0030ae93bd196sm12301884wrr.21.2023.06.12.05.29.06 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 12 Jun 2023 05:29:08 -0700 (PDT) Message-ID: <29924c50-cf96-13bb-ef84-4813caa3aef3@redhat.com> Date: Mon, 12 Jun 2023 14:29:05 +0200 Precedence: bulk X-Mailing-List: llvm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 To: Greg KH , Peter Zijlstra Cc: torvalds@linux-foundation.org, keescook@chromium.org, 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 References: <20230612090713.652690195@infradead.org> <20230612093540.850386350@infradead.org> <20230612094400.GG4253@hirez.programming.kicks-ass.net> <2023061213-knapsack-moonlike-e595@gregkh> From: Paolo Bonzini Subject: Re: [PATCH v3 46/57] perf: Simplify pmu_dev_alloc() In-Reply-To: <2023061213-knapsack-moonlike-e595@gregkh> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 6/12/23 14:18, Greg KH wrote: > Yeah, it's a pain, but you are trying to hand-roll code that is not a > "normal" path for a struct device, sorry. > > I don't know if you really can encode all of that crazy logic in the > cleanup api, UNLESS you can "switch" the cleanup function at a point in > time (i.e. after device_add() is successful). Is that possible? What _could_ make sense is that device_add() completely takes ownership of the given pointer, and takes care of calling put_device() on failure. Then you can have struct device *dev_struct __free(put_device) = kzalloc(sizeof(struct device), GFP_KERNEL); struct device *dev __free(device_del) = device_add(no_free_ptr(dev_struct)); /* dev_struct is NULL now */ pmu->dev = no_free_ptr(dev); Paolo