From mboxrd@z Thu Jan 1 00:00:00 1970 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.subspace.kernel.org (Postfix) with ESMTPS id 9E47A15D1 for ; Tue, 17 Jun 2025 04:40:00 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750135201; cv=none; b=AS2+Wok+Qjcow9hTbIr4E3KkcDCgN9YtzLUCh0uWlUSseAFONP9rDOVWlFoceY+6A8k8cFagXSbkmErgAXXCYVJyYEkLTuO5+j/hUZ2GYdtnDmtX2igiaARVPnk9tKuP1rccUCkDt07bLZI1V3kWJ3QHuQ6WRrUiAf3bLTRIzEM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750135201; c=relaxed/simple; bh=3nh5L7iPIsUx0zUfs98qLa0UUoHYjC5rXzn2MViv8L4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=a96P46oyyNfgkenlTHUqwzQ6sTDH/SJ5P/U4y+sh0ilpDKyB/uULopK8vzK+Kbgj/WYnCxuE6Fwg5iBgiuvE+eFAwG/dsm2nybA8Y+djJUWFe1RWXPTuPy9a12U1EooTENND8vJEdxL2vVgUwnlpKjb78U19TuUS4Ipmyy+iDWM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=nxwFOw+i; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="nxwFOw+i" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=MNM4kV+A6F/UHTs5MZt4D4Jc7133C1H/8+7BqWG7YPM=; b=nxwFOw+iMuTbJj9X7olnrnS+p2 ECZLs4q5NXQvjDke5LwaCnmfHotWj6J1FfJ25rnLbkrSAzEszdMTxzrY582XsW2NrOgNkexlxSCTA l7VUHgeIRDO/Ea+08Dkx79i9tcbX96zrWvzQaWfhA/oXlr7/HWD1XqsVvQvIOM6PyLO7V2hXfqWzM 7zPLqounNhOM21tkycry0JKo7MsjVPGztcJsyoL+oDwcxvFjfuRV10/Rfxhovr+AMINTn6QtRtTrC +IhDDZJ8gyCGNQyirOqRf8Oy0ykUE7iwyAkE2aMvfxJYBl6C+0CWRqMFpL1Pc6LDUVJDQC2tTfiQH 6+P0UG+Q==; Received: from hch by bombadil.infradead.org with local (Exim 4.98.2 #2 (Red Hat Linux)) id 1uRO75-00000006BV4-2Rhz; Tue, 17 Jun 2025 04:39:59 +0000 Date: Mon, 16 Jun 2025 21:39:59 -0700 From: Christoph Hellwig To: Ming Lei Cc: Caleb Sander Mateos , Christoph Hellwig , Jens Axboe , "Mohamed Abuelfotoh, Hazem" , "linux-block@vger.kernel.org" Subject: Re: [PATCH] block: use plug request list tail for one-shot backmerge attempt Message-ID: References: <045d300e-9b52-4ead-8664-2cea6354f5bf@kernel.dk> <505e4900-b814-47cd-9572-c0172fa0d01e@kernel.dk> <2de604b5-0f57-4f41-84a1-aa6f3130d7c8@kernel.dk> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Tue, Jun 17, 2025 at 10:36:06AM +0800, Ming Lei wrote: [full quote deleted, please fix your mailer] > > ublk_cmd_list_tw_cb() doesn't need a doubly-linked list. It should be > > fine to continue storing just the first struct request * of the list > > in struct ublk_uring_cmd_pdu. That would avoid growing > > ublk_uring_cmd_pdu past the 32-byte limit. > > Agree. > > ublk needn't re-order, and doubly-linked list is useless here. No driver needs to reorder, it just needs to consume the list passed to it, for which using list_cut_before is really useful. Just passing it on would be optimal, but if that can't work the frankenlist proposed by Caleb might work.