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([2001:16b8:48da:6b00:34d4:fc5b:d862:dbd2]) by smtp.gmail.com with ESMTPSA id q10sm36672783wrv.95.2020.04.19.06.15.05 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sun, 19 Apr 2020 06:15:05 -0700 (PDT) Subject: Re: [PATCH 0/5] export __clear_page_buffers to cleanup code To: Matthew Wilcox Cc: linux-fsdevel@vger.kernel.org References: <20200418225123.31850-1-guoqing.jiang@cloud.ionos.com> <20200419031443.GT5820@bombadil.infradead.org> From: Guoqing Jiang Message-ID: Date: Sun, 19 Apr 2020 15:15:04 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.4.1 MIME-Version: 1.0 In-Reply-To: <20200419031443.GT5820@bombadil.infradead.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On 19.04.20 05:14, Matthew Wilcox wrote: > On Sun, Apr 19, 2020 at 12:51:18AM +0200, Guoqing Jiang wrote: >> When reading md code, I find md-bitmap.c copies __clear_page_buffers from >> buffer.c, and after more search, seems there are some places in fs could >> use this function directly. So this patchset tries to export the function >> and use it to cleanup code. > OK, I see why you did this, but there are a couple of problems with it. > > One is just a sequencing problem; between exporting __clear_page_buffers() > and removing it from the md code, the md code won't build. Thank for reminder, I missed that. > More seriously, most of this code has nothing to do with buffers. It > uses page->private for its own purposes. > > What I would do instead is add: > > clear_page_private(struct page *page) > { > ClearPagePrivate(page); > set_page_private(page, 0); > put_page(page); > } > > to include/linux/mm.h, then convert all callers of __clear_page_buffers() > to call that instead. > Thanks for your suggestion! Thanks, Guoqing