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 3755D2BAF7; Mon, 4 Aug 2025 14:08:41 +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=1754316522; cv=none; b=nmpXgCA2/Y4aN7AVPbd6E5v2wxO7k0ffWoQwpEOryB+ktLEDNyXig+N4JeeUNAj1bputfwLS2Eihw0eJOvWc47D6n4u7R8mXykF72U2TMJhhhq5tXWb0pwX8SpOfn6m+4rYgtCafXGOKJv4fBk7a+jqWR/FMs+fpV4KsJV8bIV4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754316522; c=relaxed/simple; bh=+7Q4LotkGwU5ARZYTGNnCuBdetHLX3DRgjQvtKWhXzg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=VvRTePtynmMSRvJRYINB8rH98KWNAsK+kXjGqOFz22kXOc8z0bbsSfNK1yyVAzKxfRtq5o1ROf37AZc6F4+69guTvwiGNxgwmJ5VG9ivAGg34b3WiNrI9l0AldV20awDSwiHKkiUUBWk7w0MmwLPjiBmVQeOooNMeLOroD9fmrc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Ls0/4rEz; 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="Ls0/4rEz" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 040E7C4CEE7; Mon, 4 Aug 2025 14:08:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754316521; bh=+7Q4LotkGwU5ARZYTGNnCuBdetHLX3DRgjQvtKWhXzg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Ls0/4rEzghBmvR0vP8lQ63jV9Ne2vih9EuPhtx0lfJsVSWafCSD8lowTwlYCWSWH3 iAJoAfO8H7B7MLKxPxBO9SG6lBdmVrr2brAy4i5atmiM+4sXCE4pzamyRou9a2izWt 1gKTF7IFQ6ez+NqItBxcSbZ9lFCzk/wmuHE9YRFrJcijTUag6F08uIlDle8P1fMMOU +naPsw+VTvORrZ93ujPN8krJKyIL7XapyEx9868EnbA78ubsDdJDV7yrzGl/iVy7vw vkNK730Ir8W4L8YtoEynIHYQD8/Glt5GvaR26s+rQB7y6vebZKiifieCcXEpd/BhVu wM5VBUhVvk+fg== Date: Mon, 4 Aug 2025 08:08:38 -0600 From: Keith Busch To: Hannes Reinecke Cc: Keith Busch , linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, snitzer@kernel.org, axboe@kernel.dk, dw@davidwei.uk, brauner@kernel.org Subject: Re: [PATCH 2/7] block: align the bio after building it Message-ID: References: <20250801234736.1913170-1-kbusch@meta.com> <20250801234736.1913170-3-kbusch@meta.com> <14c5a629-2169-4271-97b8-a1aba45a6e54@suse.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: <14c5a629-2169-4271-97b8-a1aba45a6e54@suse.de> On Mon, Aug 04, 2025 at 08:54:00AM +0200, Hannes Reinecke wrote: > On 8/2/25 01:47, Keith Busch wrote: > > +static int bio_align_to_lbs(struct bio *bio, struct iov_iter *iter) > > +{ > > + struct block_device *bdev = bio->bi_bdev; > > + size_t nbytes; > > + > > + if (!bdev) > > + return 0; > > + > > + nbytes = bio->bi_iter.bi_size & (bdev_logical_block_size(bdev) - 1); > > + if (!nbytes) > > + return 0; > > + > > + bio_revert(bio, nbytes); > > + iov_iter_revert(iter, nbytes); > > + if (!bio->bi_iter.bi_size) > > + return -EFAULT; > > + > > + return 0; > > +} > > + > > /** > > * bio_iov_iter_get_pages - add user or kernel pages to a bio > > * @bio: bio to add pages to > > @@ -1336,6 +1355,7 @@ int bio_iov_iter_get_pages(struct bio *bio, struct iov_iter *iter) > > ret = __bio_iov_iter_get_pages(bio, iter); > > } while (!ret && iov_iter_count(iter) && !bio_full(bio, 0)); > > + ret = bio_align_to_lbs(bio, iter); > > return bio->bi_vcnt ? 0 : ret; > > Wouldn't that cause the error from bio_align_to_lba() to be ignored > if bio->bi_vcnt is greater than 0? That returns an error only if the alignment reduces the size to 0, so there would be a bug somewhere if bi_vcnt is not also 0 in that case.