From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-124.freemail.mail.aliyun.com (out30-124.freemail.mail.aliyun.com [115.124.30.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C32AD1F541E; Tue, 23 Dec 2025 02:32:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766457138; cv=none; b=jkBVRvqiYc6/xXVVTVAsGy1Mik6Sm9q1eyacAoh8nt5j69BkOH0ye/iYbn/LqILNPB/dQlnExSFzyLa4vQg4348xv05r1SYJZTf4BUDgTu0LW39Cxxwo13ng8/RmsLQiOZYvxLexm7AJzClpUtAJh16XSajjmQ4bLeddxJr82lk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766457138; c=relaxed/simple; bh=aGQcFcA6rVDBuzg6qgXgqURPfKInCJoPm6VQAiDCtL0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=iPnikTmX+eIaRKYm3ywg/TMoykygNr7R/Un8yIXHLXJeLZZmSW1Di3jdkyRPFvon8/KzU3EC5B191FecbAJD/XZ7fElBXzNT6Gp5Ott8SwE0ypaZIzzImMm+2DRFI+gZCkC1Zf2yOtNCpzyNmEYrbZ7XMl+6L7qNXbBAurgd5qA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=hDlmawTr; arc=none smtp.client-ip=115.124.30.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="hDlmawTr" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1766457130; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=P7yuWWW0S7jbDDkt/SoyrOQc7euoUuNF2KjMNdz0I+g=; b=hDlmawTrQh21w/t5FT1w29E8bm623kKu36hl1AgVXxRG3SKUGPjlKRsuVbZsFttcJn6Wf15dluZyOw+Nm0TYtVHKN9rmLdfoGDfgW9x00g5LeV2th9KKOCZhidDpu/sSaRrlnzebjjdk9YPVCJ564+G49ppB4HofvtmlGdmxLT4= Received: from 30.221.131.244(mailfrom:hsiangkao@linux.alibaba.com fp:SMTPD_---0WvW2.0d_1766457128 cluster:ay36) by smtp.aliyun-inc.com; Tue, 23 Dec 2025 10:32:09 +0800 Message-ID: <665e4ff3-0289-431b-b718-4cf71925fc29@linux.alibaba.com> Date: Tue, 23 Dec 2025 10:32:08 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v10 01/10] iomap: stash iomap read ctx in the private field of iomap_iter To: Hongbo Li , chao@kernel.org, brauner@kernel.org, djwong@kernel.org, amir73il@gmail.com, hch@lst.de Cc: linux-fsdevel@vger.kernel.org, linux-erofs@lists.ozlabs.org, linux-kernel@vger.kernel.org References: <20251223015618.485626-1-lihongbo22@huawei.com> <20251223015618.485626-2-lihongbo22@huawei.com> From: Gao Xiang In-Reply-To: <20251223015618.485626-2-lihongbo22@huawei.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2025/12/23 09:56, Hongbo Li wrote: > It's useful to get filesystem-specific information using the > existing private field in the @iomap_iter passed to iomap_{begin,end} > for advanced usage for iomap buffered reads, which is much like the > current iomap DIO. > > For example, EROFS needs it to: > > - implement an efficient page cache sharing feature, since iomap > needs to apply to anon inode page cache but we'd like to get the > backing inode/fs instead, so filesystem-specific private data is > needed to keep such information; > > - pass in both struct page * and void * for inline data to avoid > kmap_to_page() usage (which is bogus). > > Signed-off-by: Hongbo Li Reviewed-by: Gao Xiang Thanks, Gao Xiang