From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.loongson.cn (mail.loongson.cn [114.242.206.163]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 5A3A922EEF; Fri, 26 Jul 2024 02:13:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=114.242.206.163 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721960009; cv=none; b=ZUiMNI5zYzhUyEeUxX0NYHU9vTY+vrhzB7uxBUd+l8WCG+qRaT13Igd9jok1zTGNiNWLR3h1TqpOKAi8RbYCHjfUldtPbBZFO+NMeZchsD3TsxBIQJMlNWpq3MmfQZOKqs/QeclEucSy6kjsemi5xck1dACuGEntywYNTMyCU7o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721960009; c=relaxed/simple; bh=HqY4XQUSLvr0yzGY1uG570fMO9Gjd2nrXF8D75jC9bQ=; h=Subject:To:Cc:References:From:Message-ID:Date:MIME-Version: In-Reply-To:Content-Type; b=bT7ZcwofIFwfE71o889TJVBtzV+PbwX1coZw32xW5y+MaILrK4MOy/QqMeJIUYl3M6aXZ9x6WIQ0IN+GNHke9aDpwGw314A4BZI341AOiLjmfBLlnAOihWEfenBAaqXvzpJE713SNe5T6PWaNHQdnkahxKIdZSaqM7Aohf6qKYM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=loongson.cn; spf=pass smtp.mailfrom=loongson.cn; arc=none smtp.client-ip=114.242.206.163 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=loongson.cn Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=loongson.cn Received: from loongson.cn (unknown [10.20.42.62]) by gateway (Coremail) with SMTP id _____8Dxi+pDBqNmjd0BAA--.7089S3; Fri, 26 Jul 2024 10:13:23 +0800 (CST) Received: from [10.20.42.62] (unknown [10.20.42.62]) by front1 (Coremail) with SMTP id qMiowMCx2sVABqNmTQ0CAA--.11809S3; Fri, 26 Jul 2024 10:13:22 +0800 (CST) Subject: Re: [PATCH] LoongArch: KVM: Remove redundant assignment in kvm_map_page_fast To: tangbin , zhaotianrui@loongson.cn, chenhuacai@kernel.org, kernel@xen0n.name Cc: kvm@vger.kernel.org, loongarch@lists.linux.dev, linux-kernel@vger.kernel.org References: <20240713155937.45261-1-tangbin@cmss.chinamobile.com> From: maobibo Message-ID: <286be0a6-dac3-b2cd-e88a-e6feb5a240de@loongson.cn> Date: Fri, 26 Jul 2024 10:13:19 +0800 User-Agent: Mozilla/5.0 (X11; Linux loongarch64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <20240713155937.45261-1-tangbin@cmss.chinamobile.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-CM-TRANSID:qMiowMCx2sVABqNmTQ0CAA--.11809S3 X-CM-SenderInfo: xpdruxter6z05rqj20fqof0/ X-Coremail-Antispam: 1Uk129KBj93XoW7Ww1Dur4rtr17Zry3XryDXFc_yoW8Kw17pr ZIkrnrCr4rtr1FkFZrta4DCFy29395KryxXa4Ig34rXwnFqr1Yq3W8X3yDZFy5J3ykZayS qF4rJ3WUuan0yacCm3ZEXasCq-sJn29KB7ZKAUJUUUU5529EdanIXcx71UUUUU7KY7ZEXa sCq-sGcSsGvfJ3Ic02F40EFcxC0VAKzVAqx4xG6I80ebIjqfuFe4nvWSU5nxnvy29KBjDU 0xBIdaVrnRJUUUvFb4IE77IF4wAFF20E14v26r1j6r4UM7CY07I20VC2zVCF04k26cxKx2 IYs7xG6rWj6s0DM7CIcVAFz4kK6r1Y6r17M28lY4IEw2IIxxk0rwA2F7IY1VAKz4vEj48v e4kI8wA2z4x0Y4vE2Ix0cI8IcVAFwI0_JFI_Gr1l84ACjcxK6xIIjxv20xvEc7CjxVAFwI 0_Gr0_Cr1l84ACjcxK6I8E87Iv67AKxVWxJVW8Jr1l84ACjcxK6I8E87Iv6xkF7I0E14v2 6r4j6r4UJwAS0I0E0xvYzxvE52x082IY62kv0487Mc804VCY07AIYIkI8VC2zVCFFI0UMc 02F40EFcxC0VAKzVAqx4xG6I80ewAv7VC0I7IYx2IY67AKxVWUXVWUAwAv7VC2z280aVAF wI0_Jr0_Gr1lOx8S6xCaFVCjc4AY6r1j6r4UM4x0Y48IcVAKI48JMxk0xIA0c2IEe2xFo4 CEbIxvr21l42xK82IYc2Ij64vIr41l4I8I3I0E4IkC6x0Yz7v_Jr0_Gr1lx2IqxVAqx4xG 67AKxVWUJVWUGwC20s026x8GjcxK67AKxVWUGVWUWwC2zVAF1VAY17CE14v26r126r1DMI IYrxkI7VAKI48JMIIF0xvE2Ix0cI8IcVAFwI0_Jr0_JF4lIxAIcVC0I7IYx2IY6xkF7I0E 14v26r1j6r4UMIIF0xvE42xK8VAvwI8IcIk0rVWUJVWUCwCI42IY6I8E87Iv67AKxVWUJV W8JwCI42IY6I8E87Iv6xkF7I0E14v26r4j6r4UJbIYCTnIWIevJa73UjIFyTuYvjxU7_Ma UUUUU Hi Tangbin, There is only return value with -EFAULT or 0 in function kvm_map_page_fast(), if there is better error code or different error for new code, the situation will be different :) I would like to keep existing code unchanged, however thanks for your patch. Regards Bibo Mao On 2024/7/13 下午11:59, tangbin wrote: > In the function kvm_map_page_fast, the assignment of 'ret' is > redundant, so remove it. > > Signed-off-by: tangbin > --- > arch/loongarch/kvm/mmu.c | 17 +++++------------ > 1 file changed, 5 insertions(+), 12 deletions(-) > > diff --git a/arch/loongarch/kvm/mmu.c b/arch/loongarch/kvm/mmu.c > index 2634a9e8d..d6c922a4a 100644 > --- a/arch/loongarch/kvm/mmu.c > +++ b/arch/loongarch/kvm/mmu.c > @@ -551,7 +551,6 @@ bool kvm_test_age_gfn(struct kvm *kvm, struct kvm_gfn_range *range) > */ > static int kvm_map_page_fast(struct kvm_vcpu *vcpu, unsigned long gpa, bool write) > { > - int ret = 0; > kvm_pfn_t pfn = 0; > kvm_pte_t *ptep, changed, new; > gfn_t gfn = gpa >> PAGE_SHIFT; > @@ -563,20 +562,16 @@ static int kvm_map_page_fast(struct kvm_vcpu *vcpu, unsigned long gpa, bool writ > > /* Fast path - just check GPA page table for an existing entry */ > ptep = kvm_populate_gpa(kvm, NULL, gpa, 0); > - if (!ptep || !kvm_pte_present(NULL, ptep)) { > - ret = -EFAULT; > + if (!ptep || !kvm_pte_present(NULL, ptep)) > goto out; > - } > > /* Track access to pages marked old */ > new = kvm_pte_mkyoung(*ptep); > /* call kvm_set_pfn_accessed() after unlock */ > > if (write && !kvm_pte_dirty(new)) { > - if (!kvm_pte_write(new)) { > - ret = -EFAULT; > + if (!kvm_pte_write(new)) > goto out; > - } > > if (kvm_pte_huge(new)) { > /* > @@ -584,10 +579,8 @@ static int kvm_map_page_fast(struct kvm_vcpu *vcpu, unsigned long gpa, bool writ > * enabled for HugePages > */ > slot = gfn_to_memslot(kvm, gfn); > - if (kvm_slot_dirty_track_enabled(slot)) { > - ret = -EFAULT; > + if (kvm_slot_dirty_track_enabled(slot)) > goto out; > - } > } > > /* Track dirtying of writeable pages */ > @@ -615,10 +608,10 @@ static int kvm_map_page_fast(struct kvm_vcpu *vcpu, unsigned long gpa, bool writ > if (page) > put_page(page); > } > - return ret; > + return 0; > out: > spin_unlock(&kvm->mmu_lock); > - return ret; > + return -EFAULT; > } > > static bool fault_supports_huge_mapping(struct kvm_memory_slot *memslot, >