From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id A097EC36010 for ; Mon, 7 Apr 2025 14:02:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=R2aCLNE+3J8JH3+xqlduVzVtsfGJDj97LfEiDFkzUHY=; b=dVYVoqFj6aQ0RD tjFb4Y0bW5c0FgaxqxR5yBx7SyeYskXHhMOW03HHl9YRnxDfvbVzMj1bqAsN0is589FOmIX+1D7WP 5wiyvg8xFtCWa78pChYxJZNQkLZuYIYZPzI3wDoDQVGKPVI13y7Wyw1OuQCAMp5eCvAkCQjhbDOiM KizM32doNBCoFmDz3dnKQLA7KrOvCMKSf5LbsZ4dJq4DM7qz4v/sk5yJ9o96N46vi8VGkgPH0YapJ 3PRiM+45l1uMDP7p0wjPTqT7UTTDM5N1rJmnxFnTHzAjRKNdFdDGyiY23tDfQ7yYlyTtuzcpXu6Ls RS0MnBa9TIoeNqq9RoNA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.1 #2 (Red Hat Linux)) id 1u1n2v-00000000dnS-3ImH; Mon, 07 Apr 2025 14:01:53 +0000 Received: from hch by bombadil.infradead.org with local (Exim 4.98.1 #2 (Red Hat Linux)) id 1u1n11-00000000dNi-4BVx; Mon, 07 Apr 2025 13:59:55 +0000 Date: Mon, 7 Apr 2025 06:59:55 -0700 From: Christoph Hellwig To: Keith Busch Cc: Christoph Hellwig , Sean Anderson , Jens Axboe , linux-block@vger.kernel.org, Miquel Raynal , Richard Weinberger , Vignesh Raghavendra , linux-mtd@lists.infradead.org, Zhihao Cheng Subject: Re: bio segment constraints Message-ID: References: <8dfd97ac-59e7-ae69-238a-85b7a2dae4f1@gmail.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org On Mon, Apr 07, 2025 at 02:46:32PM +0100, Keith Busch wrote: > > > - Is is possible to have segments not even aligned to SECTOR_SIZE? > > > > No. > > O_DIRECT only requires each user iovec be a multiple of the logical > block size with the address aligned to the dma_alignment. If the > dma_alignment is smaller than the logical block size, then this could > create bvec segments that are smaller. For nvme where we have 4-byte > dma alignment, you could have the first segment be the last 4 bytes of a > page, then the remaing 508 bytes from a different page in the next > segment. Oh, right - with a smaller dma alignment this can actually happen. ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/