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Thu, 06 Feb 2020 11:36:43 -0800 (PST) X-Google-Smtp-Source: APXvYqzatdWQ9u1Csyt6ZBqzWmkIODyw51F4x3+ll70oC84aFgUA9YxLV7t3Xset8ndnG7nclcebeQ== X-Received: by 2002:ac8:42c6:: with SMTP id g6mr4191461qtm.250.1581017803755; Thu, 06 Feb 2020 11:36:43 -0800 (PST) Received: from xz-x1 ([2607:9880:19c8:32::2]) by smtp.gmail.com with ESMTPSA id e64sm135332qtd.45.2020.02.06.11.36.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 06 Feb 2020 11:36:43 -0800 (PST) Date: Thu, 6 Feb 2020 14:36:40 -0500 From: Peter Xu To: Sean Christopherson Subject: Re: [PATCH v5 14/19] KVM: Clean up local variable usage in __kvm_set_memory_region() Message-ID: <20200206193640.GB700495@xz-x1> References: <20200121223157.15263-1-sean.j.christopherson@intel.com> <20200121223157.15263-15-sean.j.christopherson@intel.com> <20200206190641.GA700495@xz-x1> <20200206192230.GE13067@linux.intel.com> MIME-Version: 1.0 In-Reply-To: <20200206192230.GE13067@linux.intel.com> X-MC-Unique: HKmpGfLKPx67ZxhCtGYB8g-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Disposition: inline X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200206_113650_293871_7818374D X-CRM114-Status: GOOD ( 16.17 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Wanpeng Li , kvm@vger.kernel.org, David Hildenbrand , linux-mips@vger.kernel.org, Paul Mackerras , kvmarm@lists.cs.columbia.edu, Janosch Frank , Marc Zyngier , Joerg Roedel , Christian Borntraeger , Julien Thierry , Suzuki K Poulose , kvm-ppc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Jim Mattson , Cornelia Huck , Christoffer Dall , linux-kernel@vger.kernel.org, James Morse , Paolo Bonzini , Vitaly Kuznetsov , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, Feb 06, 2020 at 11:22:30AM -0800, Sean Christopherson wrote: > On Thu, Feb 06, 2020 at 02:06:41PM -0500, Peter Xu wrote: > > On Tue, Jan 21, 2020 at 02:31:52PM -0800, Sean Christopherson wrote: > > > > [...] > > > > > @@ -1101,52 +1099,55 @@ int __kvm_set_memory_region(struct kvm *kvm, > > > if (mem->guest_phys_addr + mem->memory_size < mem->guest_phys_addr) > > > return -EINVAL; > > > > > > - slot = id_to_memslot(__kvm_memslots(kvm, as_id), id); > > > - base_gfn = mem->guest_phys_addr >> PAGE_SHIFT; > > > - npages = mem->memory_size >> PAGE_SHIFT; > > > - > > > - if (npages > KVM_MEM_MAX_NR_PAGES) > > > - return -EINVAL; > > > - > > > /* > > > * Make a full copy of the old memslot, the pointer will become stale > > > * when the memslots are re-sorted by update_memslots(). > > > */ > > > - old = *slot; > > > + tmp = id_to_memslot(__kvm_memslots(kvm, as_id), id); > > > + old = *tmp; > > > + tmp = NULL; > > > > Shall we keep this chunk to the patch where it will be used? Other > > than that, it looks good to me. > > I assume you're talking about doing this instead of using @tmp? > > old = *id_to_memslot(__kvm_memslots(kvm, as_id), id); Yes. > > It's obviously possible, but I really like resulting diff for > __kvm_set_memory_region() in "KVM: Terminate memslot walks via used_slots" > when tmp is used. > > @@ -1104,8 +1203,13 @@ int __kvm_set_memory_region(struct kvm *kvm, > * when the memslots are re-sorted by update_memslots(). > */ > tmp = id_to_memslot(__kvm_memslots(kvm, as_id), id); > - old = *tmp; > - tmp = NULL; > + if (tmp) { > + old = *tmp; > + tmp = NULL; > + } else { > + memset(&old, 0, sizeof(old)); > + old.id = id; > + } I normally don't do that, for each patch I'll try to make it consistent to itself, assuming that follow-up patches can be rejected. I don't have strong opinion either, please feel free to keep them if no one disagrees. -- Peter Xu _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel