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X-CSE-ConnectionGUID: mtpk29KxTlmAeNyGjYs7NA== X-CSE-MsgGUID: ij0AKKw1ROmVSsr1ATv+yg== X-IronPort-AV: E=McAfee;i="6800,10657,11618"; a="83019113" X-IronPort-AV: E=Sophos;i="6.19,316,1754982000"; d="scan'208";a="83019113" Received: from fmviesa004.fm.intel.com ([10.60.135.144]) by orvoesa102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Nov 2025 10:05:39 -0800 X-CSE-ConnectionGUID: KcS2ZiaIT+a8jastHnb/eQ== X-CSE-MsgGUID: U8N+6szcQvqbZcU2xVNDHQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.19,316,1754982000"; d="scan'208";a="196077407" Received: from puneetse-mobl.amr.corp.intel.com (HELO [10.125.109.180]) ([10.125.109.180]) by fmviesa004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Nov 2025 10:05:38 -0800 Message-ID: Date: Wed, 19 Nov 2025 10:05:37 -0800 Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v1 06/26] x86/virt/tdx: Add tdx_page_array helpers for new TDX Module objects To: dan.j.williams@intel.com, Xu Yilun , linux-coco@lists.linux.dev, linux-pci@vger.kernel.org Cc: chao.gao@intel.com, dave.jiang@intel.com, baolu.lu@linux.intel.com, yilun.xu@intel.com, zhenzhong.duan@intel.com, kvm@vger.kernel.org, rick.p.edgecombe@intel.com, dave.hansen@linux.intel.com, kas@kernel.org, x86@kernel.org References: <20251117022311.2443900-1-yilun.xu@linux.intel.com> <20251117022311.2443900-7-yilun.xu@linux.intel.com> <70056924-1702-4020-b805-014efb87afdd@intel.com> <691dee3f569dc_1aaf41001e@dwillia2-mobl4.notmuch> From: Dave Hansen Content-Language: en-US Autocrypt: addr=dave.hansen@intel.com; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 11/19/25 08:20, dan.j.williams@intel.com wrote: > Please document that tip prefers that goto be used in cases where a > single goto target can be used. I don't think it's that hard and fast of a rule. It's really just a more general: use the best tool for the job. For instance, if your line of code was already on the long side, the additional __free(foo) might be the straw that breaks the camel's back. So it all depends. In this case, we have very linear code flow, very long lines, and quite uniform allocator use (they can all be kfree()). That tips the scales squarely in the direction of goto. Dan, you were also concerned about the mental load of ensuring that the error goto code frees objects in reverse allocation order. I certainly understand that inclination. But there's already code that takes that allocation order into account. It's also going to be in this patch whether or not __free() is utilized: > +void tdx_page_array_free(struct tdx_page_array *array) > +{ > + if (!array) > + return; > + > + __free_page(array->root); > + tdx_free_pages_bulk(array->nr_pages, array->pages); > + kfree(array->pages); > + kfree(array); > +} Ideally, we'd be able to define the free ordering requirements in a single bit of code and use it in both paths.