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([2620:15c:2cd:203:5cdc:422c:7b28:ebb5]) by smtp.gmail.com with ESMTPSA id 27-v6sm7652440pfm.36.2018.11.08.15.42.20 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 08 Nov 2018 15:42:20 -0800 (PST) Message-ID: <1541720539.196084.236.camel@acm.org> Subject: Re: [driver-core PATCH v5 5/9] driver core: Establish clear order of operations for deferred probe and remove From: Bart Van Assche To: Joe Perches , Alexander Duyck , linux-kernel@vger.kernel.org, gregkh@linuxfoundation.org Cc: linux-nvdimm@lists.01.org, tj@kernel.org, akpm@linux-foundation.org, linux-pm@vger.kernel.org, jiangshanlai@gmail.com, rafael@kernel.org, len.brown@intel.com, pavel@ucw.cz, zwisler@kernel.org, dan.j.williams@intel.com, dave.jiang@intel.com Date: Thu, 08 Nov 2018 15:42:19 -0800 In-Reply-To: <499e4358e72fca510fa6fcfb76ea3ac3792db08f.camel@perches.com> References: <154145223352.29224.8912797012647157172.stgit@ahduyck-desk1.jf.intel.com> <154145232484.29224.1635232599636954462.stgit@ahduyck-desk1.jf.intel.com> <1541548114.196084.195.camel@acm.org> <499e4358e72fca510fa6fcfb76ea3ac3792db08f.camel@perches.com> Content-Type: text/plain; charset="UTF-7" X-Mailer: Evolution 3.26.2-1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2018-11-06 at 17:34 -0800, Joe Perches wrote: +AD4 On Tue, 2018-11-06 at 15:48 -0800, Bart Van Assche wrote: +AD4 +AD4 On Mon, 2018-11-05 at 13:12 -0800, Alexander Duyck wrote: +AD4 +AD4 +AD4 One change I made in addition is I replaced the use of +ACI-bool X:1+ACI to define +AD4 +AD4 +AD4 the bitfield to a +ACI-u8 X:1+ACI setup in order to resolve some checkpatch +AD4 +AD4 +AD4 warnings. +AD4 +AD4 +AD4 +AD4 Please use +ACI-bool X:1+ACI instead of +ACI-u8 X:1+ACI. I think it was a bad idea to make +AD4 +AD4 checkpatch complain about +ACI-bool X:1+ACI since +ACI-bool X:1+ACI should only be avoided +AD4 +AD4 in structures for which alignment must be architecture-independent. For struct +AD4 +AD4 device it is fine if member alignment differs per architecture. Additionally, +AD4 +AD4 changing +ACI-bool X:1+ACI into +ACI-u8 X:1+ACI will reduce performance on architectures that +AD4 +AD4 cannot do byte addressing. +AD4 +AD4 I generally agree. But the checkpatch warning +AF8-could+AF8 +AD4 be useful in those cases where alignment should be +AD4 architecture-independent. +AD4 +AD4 Any suggestion on how to improve the message? It would be great if a heuristic could be developed that recognizes structs for which the data layout must be architecture independent. If such a heuristic could be developed it could be used to only display warn about +ACI-bool X:n+ACI for such structures. Bart.