From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 55E62359F8B for ; Tue, 11 Nov 2025 13:54:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762869297; cv=none; b=e2RoE4Heqdc7BBUML2NoyXQ68M7wmGkDcWXLJSV8zrHVC1cIPBbLC+/HW1gLwv9xH7n0QeP5bhjqkngKkMCys/IZ+S9KHCY0jOQTR5SFGni0/cYKIF6fhi7mxnxuRnp5N/wxfG8ktmn4NvT2XBxr95TYMQwGWV7JtvB4s5Mm0tM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762869297; c=relaxed/simple; bh=nOjcrcHGqxzAQp5BO2Cm52zJa3SqUoYXtMLRHzvTVtI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=A9K33/WQUQ7N/Q6jUBcLcleL4yvH7WMP6QSrxNWzXynlDZIFTbrJnGZtGArnL13E6839o3VT6/5uSqbMzIxCjDIUqA9t7IDj27IRaeBATdTmTUlqFMWwARgKTwFIgV+4swkiQfv0pcg8QrApFl6thyiJ6GaUo8bVcKsAeHtADr4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=cR/enPMS; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="cR/enPMS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id EA66AC2BC86; Tue, 11 Nov 2025 13:54:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762869296; bh=nOjcrcHGqxzAQp5BO2Cm52zJa3SqUoYXtMLRHzvTVtI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=cR/enPMSVXBmha2JWczFTQ+NgUpPrn5hrDvzKs7WeEs4DEGMZyaZ6CpbfniLOhsqZ dS9PfcGrM+TVsFwml4P3Vo1PU6uja8lBezcuM3o6VcS/DlCSld6ayj0S4bbq3jIKlQ bA/NMPpMA929pCe4RvFEUVGGbnEf+slJEO0OzB2IajM5VEkMpdVQctQFYOuryum0a8 i8Dw3OfRFCLf0/H527TT7CZFQ8owejxH7gpQK1D5WlX1ouHI8sagItArFPdOGcVlGo 6oIqca/3QQG6bIhDTzOoXhhu1OpDevwu6+ra/GOV7XDyeX6qgv1sZOyxZNhMVG7924 KMjwh6bhEnjBg== Date: Tue, 11 Nov 2025 08:54:53 -0500 From: Keith Busch To: Christoph Hellwig Cc: Yu Kuai , Matthew Wilcox , Keith Busch , linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, axboe@kernel.dk Subject: Re: [PATCHv5 1/2] block: accumulate memory segment gaps per bio Message-ID: References: <20251014150456.2219261-1-kbusch@meta.com> <20251014150456.2219261-2-kbusch@meta.com> <20251111071439.GA4240@lst.de> <024631dc-3c65-49a8-a97a-f9110fd00e9a@fnnas.com> <20251111093903.GB14438@lst.de> <20251111134001.GA708@lst.de> 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: <20251111134001.GA708@lst.de> On Tue, Nov 11, 2025 at 02:40:01PM +0100, Christoph Hellwig wrote: > On Tue, Nov 11, 2025 at 08:25:38AM -0500, Keith Busch wrote: > > Ah, so we're merging a discard for a device that doesn't support > > vectored discard. I think we still want to be able to front/back merge > > such requests, though. > > Yes, but purely based on bi_sector/bi_size, not based on the payload. This should do it: --- diff --git a/block/blk-merge.c b/block/blk-merge.c index 3ca6fbf8b7870..d3115d7469df0 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -737,6 +737,9 @@ u8 bio_seg_gap(struct request_queue *q, struct bio *prev, struct bio *next, { struct bio_vec pb, nb; + if (!bio_has_data(prev)) + return 0; + gaps_bit = min_not_zero(gaps_bit, prev->bi_bvec_gap_bit); gaps_bit = min_not_zero(gaps_bit, next->bi_bvec_gap_bit); --