From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 9045529A9E9 for ; Fri, 12 Dec 2025 02:38:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765507118; cv=none; b=SbR2l2Ox+xExFI89ohWNcwIAUYq/7VB5hIiaxzKMHCnYmAFjAJyzARJGFWjQ4AOjXvtHKhcytj1RqXql21+2wPivGYQVZLqaaIu+85t4WurUvxDzUWXM7nJRy6u8E5J2P+P48GfJxZ8js8yGiq0VWNnRen5f2KmOxygmFN00rjI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765507118; c=relaxed/simple; bh=4jVEMv5TylVWRmHeErm41ags2bC4GUsQkXiDOJVLo9w=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=fV2/nQii/beDqZXFyVg9AvEkVgd/s8IY98YS2iID7Au9EcoRyJEJX/XMVeYjYawvwuZZP/QZi6NsTg4tN2Rnjt/ELDJIQ/5V9sznoWXPzX92VihBS7zP4eHSBOXjIlEmRFCaaiSntptC652UYWaVxwjaJSSJutnZEw3/AoNV/DA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=UYOG+kaS; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="UYOG+kaS" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1765507115; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=k51ZjcIrCEC17PqRwLS2QlKbEaoT5EAKPcTuE8TUql8=; b=UYOG+kaSwNQAxN+0fH4Ve2ulv33i3FYxR0QdLuYtPj8FUE+4yvv1rTf9rK8/LCBe4xkiyJ XIYJDK4GlxNPNJxas1MMdIIHjWAogchJtfIKt+llNNjEGUSQkXet/YQa2nROhW/dyhC99d khhV717aJtxT739ERaaJNt1SrE5CJfQ= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-481-9pezzAWXPSSU4wWt9bamvw-1; Thu, 11 Dec 2025 21:38:32 -0500 X-MC-Unique: 9pezzAWXPSSU4wWt9bamvw-1 X-Mimecast-MFC-AGG-ID: 9pezzAWXPSSU4wWt9bamvw_1765507111 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id D9CE2180060D; Fri, 12 Dec 2025 02:38:30 +0000 (UTC) Received: from fedora (unknown [10.72.116.129]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 9CC18180049F; Fri, 12 Dec 2025 02:38:27 +0000 (UTC) Date: Fri, 12 Dec 2025 10:38:17 +0800 From: Ming Lei To: Caleb Sander Mateos Cc: Shuah Khan , linux-block@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 6/8] selftests: ublk: forbid multiple data copy modes Message-ID: References: <20251211051603.1154841-1-csander@purestorage.com> <20251211051603.1154841-7-csander@purestorage.com> 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=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 On Thu, Dec 11, 2025 at 06:06:51PM -0800, Caleb Sander Mateos wrote: > On Thu, Dec 11, 2025 at 3:05 PM Ming Lei wrote: > > > > On Thu, Dec 11, 2025 at 10:45:36AM -0800, Caleb Sander Mateos wrote: > > > On Thu, Dec 11, 2025 at 1:09 AM Ming Lei wrote: > > > > > > > > On Wed, Dec 10, 2025 at 10:16:01PM -0700, Caleb Sander Mateos wrote: > > > > > The kublk mock ublk server allows multiple data copy mode arguments to > > > > > be passed on the command line (--zero_copy, --get_data, and --auto_zc). > > > > > The ublk device will be created with all the requested feature flags, > > > > > however kublk will only use one of the modes to interact with request > > > > > data (arbitrarily preferring auto_zc over zero_copy over get_data). To > > > > > clarify the intent of the test, don't allow multiple data copy modes to > > > > > be specified. Don't set UBLK_F_USER_COPY for zero_copy, as it's an > > > > > independent feature. Don't require zero_copy for auto_zc_fallback, as > > > > > only auto_zc is needed. Fix the test cases passing multiple data copy > > > > > mode arguments. > > > > > > > > > > Signed-off-by: Caleb Sander Mateos > > > > > --- > > > > > tools/testing/selftests/ublk/kublk.c | 21 ++++++++++++------- > > > > > .../testing/selftests/ublk/test_generic_09.sh | 2 +- > > > > > .../testing/selftests/ublk/test_stress_03.sh | 4 ++-- > > > > > .../testing/selftests/ublk/test_stress_04.sh | 2 +- > > > > > .../testing/selftests/ublk/test_stress_05.sh | 10 ++++----- > > > > > 5 files changed, 22 insertions(+), 17 deletions(-) > > > > > > > > > > diff --git a/tools/testing/selftests/ublk/kublk.c b/tools/testing/selftests/ublk/kublk.c > > > > > index f8fa102a627f..1765c4806523 100644 > > > > > --- a/tools/testing/selftests/ublk/kublk.c > > > > > +++ b/tools/testing/selftests/ublk/kublk.c > > > > > @@ -1611,11 +1611,11 @@ int main(int argc, char *argv[]) > > > > > break; > > > > > case 'd': > > > > > ctx.queue_depth = strtol(optarg, NULL, 10); > > > > > break; > > > > > case 'z': > > > > > - ctx.flags |= UBLK_F_SUPPORT_ZERO_COPY | UBLK_F_USER_COPY; > > > > > + ctx.flags |= UBLK_F_SUPPORT_ZERO_COPY; > > > > > break; > > > > > case 'r': > > > > > value = strtol(optarg, NULL, 10); > > > > > if (value) > > > > > ctx.flags |= UBLK_F_USER_RECOVERY; > > > > > @@ -1674,17 +1674,22 @@ int main(int argc, char *argv[]) > > > > > optind += 1; > > > > > break; > > > > > } > > > > > } > > > > > > > > > > - /* auto_zc_fallback depends on F_AUTO_BUF_REG & F_SUPPORT_ZERO_COPY */ > > > > > - if (ctx.auto_zc_fallback && > > > > > - !((ctx.flags & UBLK_F_AUTO_BUF_REG) && > > > > > - (ctx.flags & UBLK_F_SUPPORT_ZERO_COPY))) { > > > > > - ublk_err("%s: auto_zc_fallback is set but neither " > > > > > - "F_AUTO_BUF_REG nor F_SUPPORT_ZERO_COPY is enabled\n", > > > > > - __func__); > > > > > + /* auto_zc_fallback depends on F_AUTO_BUF_REG */ > > > > > + if (ctx.auto_zc_fallback && !(ctx.flags & UBLK_F_AUTO_BUF_REG)) { > > > > > + ublk_err("%s: auto_zc_fallback is set but F_AUTO_BUF_REG is disabled\n", > > > > > + __func__); > > > > > + return -EINVAL; > > > > > + } > > > > > + > > > > > + if (!!(ctx.flags & UBLK_F_SUPPORT_ZERO_COPY) + > > > > > + !!(ctx.flags & UBLK_F_NEED_GET_DATA) + > > > > > + !!(ctx.flags & UBLK_F_USER_COPY) + > > > > > + !!(ctx.flags & UBLK_F_AUTO_BUF_REG) > 1) { > > > > > + fprintf(stderr, "too many data copy modes specified\n"); > > > > > return -EINVAL; > > > > > } > > > > > > > > Actually most of them are allowed to co-exist, such as -z/--auto_zc/-u. > > > > > > Yes, I know the ublk driver allows multiple copy mode flags to be set > > > (though it will clear UBLK_F_NEED_GET_DATA if any of the others are > > > set). However, kublk will only actually use one of the modes. For > > > example, --get_data --zero_copy will use zero copy for the data > > > transfer, not get data. And --zero_copy --auto_zc will only use auto > > > buffer registration. So I think it's confusing to allow multiple of > > > these parameters to be passed to kublk. Or do you think there is value > > > in testing ublk device creation with multiple data copy mode flags > > > set, but only one of the modes actually used? > > > > > > > > > > > > > > > > > i = optind; > > > > > while (i < argc && ctx.nr_files < MAX_BACK_FILES) { > > > > > diff --git a/tools/testing/selftests/ublk/test_generic_09.sh b/tools/testing/selftests/ublk/test_generic_09.sh > > > > > index bb6f77ca5522..145e17b3d2b0 100755 > > > > > --- a/tools/testing/selftests/ublk/test_generic_09.sh > > > > > +++ b/tools/testing/selftests/ublk/test_generic_09.sh > > > > > @@ -14,11 +14,11 @@ if ! _have_program fio; then > > > > > exit "$UBLK_SKIP_CODE" > > > > > fi > > > > > > > > > > _prep_test "null" "basic IO test" > > > > > > > > > > -dev_id=$(_add_ublk_dev -t null -z --auto_zc --auto_zc_fallback) > > > > > +dev_id=$(_add_ublk_dev -t null --auto_zc --auto_zc_fallback) > > > > > _check_add_dev $TID $? > > > > > > > > > > # run fio over the two disks > > > > > fio --name=job1 --filename=/dev/ublkb"${dev_id}" --ioengine=libaio --rw=readwrite --iodepth=32 --size=256M > /dev/null 2>&1 > > > > > ERR_CODE=$? > > > > > diff --git a/tools/testing/selftests/ublk/test_stress_03.sh b/tools/testing/selftests/ublk/test_stress_03.sh > > > > > index 3ed4c9b2d8c0..8e9f2786ef9c 100755 > > > > > --- a/tools/testing/selftests/ublk/test_stress_03.sh > > > > > +++ b/tools/testing/selftests/ublk/test_stress_03.sh > > > > > @@ -36,19 +36,19 @@ wait > > > > > > > > > > if _have_feature "AUTO_BUF_REG"; then > > > > > ublk_io_and_remove 8G -t null -q 4 --auto_zc & > > > > > ublk_io_and_remove 256M -t loop -q 4 --auto_zc "${UBLK_BACKFILES[0]}" & > > > > > ublk_io_and_remove 256M -t stripe -q 4 --auto_zc "${UBLK_BACKFILES[1]}" "${UBLK_BACKFILES[2]}" & > > > > > - ublk_io_and_remove 8G -t null -q 4 -z --auto_zc --auto_zc_fallback & > > > > > + ublk_io_and_remove 8G -t null -q 4 --auto_zc --auto_zc_fallback & > > > > > wait > > > > > fi > > > > > > > > > > if _have_feature "PER_IO_DAEMON"; then > > > > > ublk_io_and_remove 8G -t null -q 4 --auto_zc --nthreads 8 --per_io_tasks & > > > > > ublk_io_and_remove 256M -t loop -q 4 --auto_zc --nthreads 8 --per_io_tasks "${UBLK_BACKFILES[0]}" & > > > > > ublk_io_and_remove 256M -t stripe -q 4 --auto_zc --nthreads 8 --per_io_tasks "${UBLK_BACKFILES[1]}" "${UBLK_BACKFILES[2]}" & > > > > > - ublk_io_and_remove 8G -t null -q 4 -z --auto_zc --auto_zc_fallback --nthreads 8 --per_io_tasks & > > > > > + ublk_io_and_remove 8G -t null -q 4 --auto_zc --auto_zc_fallback --nthreads 8 --per_io_tasks & > > > > > wait > > > > > fi > > > > > > > > > > _cleanup_test "stress" > > > > > _show_result $TID $ERR_CODE > > > > > diff --git a/tools/testing/selftests/ublk/test_stress_04.sh b/tools/testing/selftests/ublk/test_stress_04.sh > > > > > index c7220723b537..6e165a1f90b4 100755 > > > > > --- a/tools/testing/selftests/ublk/test_stress_04.sh > > > > > +++ b/tools/testing/selftests/ublk/test_stress_04.sh > > > > > @@ -35,11 +35,11 @@ wait > > > > > > > > > > if _have_feature "AUTO_BUF_REG"; then > > > > > ublk_io_and_kill_daemon 8G -t null -q 4 --auto_zc & > > > > > ublk_io_and_kill_daemon 256M -t loop -q 4 --auto_zc "${UBLK_BACKFILES[0]}" & > > > > > ublk_io_and_kill_daemon 256M -t stripe -q 4 --auto_zc --no_ublk_fixed_fd "${UBLK_BACKFILES[1]}" "${UBLK_BACKFILES[2]}" & > > > > > - ublk_io_and_kill_daemon 8G -t null -q 4 -z --auto_zc --auto_zc_fallback & > > > > > + ublk_io_and_kill_daemon 8G -t null -q 4 --auto_zc --auto_zc_fallback & > > > > > wait > > > > > fi > > > > > > > > > > if _have_feature "PER_IO_DAEMON"; then > > > > > ublk_io_and_kill_daemon 8G -t null -q 4 --auto_zc --nthreads 8 --per_io_tasks & > > > > > diff --git a/tools/testing/selftests/ublk/test_stress_05.sh b/tools/testing/selftests/ublk/test_stress_05.sh > > > > > index 274295061042..09b94c36f2ba 100755 > > > > > --- a/tools/testing/selftests/ublk/test_stress_05.sh > > > > > +++ b/tools/testing/selftests/ublk/test_stress_05.sh > > > > > @@ -56,21 +56,21 @@ for reissue in $(seq 0 1); do > > > > > wait > > > > > done > > > > > > > > > > if _have_feature "ZERO_COPY"; then > > > > > for reissue in $(seq 0 1); do > > > > > - ublk_io_and_remove 8G -t null -q 4 -g -z -r 1 -i "$reissue" & > > > > > - ublk_io_and_remove 256M -t loop -q 4 -g -z -r 1 -i "$reissue" "${UBLK_BACKFILES[1]}" & > > > > > + ublk_io_and_remove 8G -t null -q 4 -z -r 1 -i "$reissue" & > > > > > + ublk_io_and_remove 256M -t loop -q 4 -z -r 1 -i "$reissue" "${UBLK_BACKFILES[1]}" & > > > > > wait > > > > > done > > > > > fi > > > > > > > > > > if _have_feature "AUTO_BUF_REG"; then > > > > > for reissue in $(seq 0 1); do > > > > > - ublk_io_and_remove 8G -t null -q 4 -g --auto_zc -r 1 -i "$reissue" & > > > > > - ublk_io_and_remove 256M -t loop -q 4 -g --auto_zc -r 1 -i "$reissue" "${UBLK_BACKFILES[1]}" & > > > > > - ublk_io_and_remove 8G -t null -q 4 -g -z --auto_zc --auto_zc_fallback -r 1 -i "$reissue" & > > > > > + ublk_io_and_remove 8G -t null -q 4 --auto_zc -r 1 -i "$reissue" & > > > > > + ublk_io_and_remove 256M -t loop -q 4 --auto_zc -r 1 -i "$reissue" "${UBLK_BACKFILES[1]}" & > > > > > + ublk_io_and_remove 8G -t null -q 4 --auto_zc --auto_zc_fallback -r 1 -i "$reissue" & > > > > > > > > --auto_zc_fallback requires both -z and --auto_zc. > > > > > > Ah, right, I forgot that the fallback path relies on normal zero copy > > > buffer registration. I guess we are missing coverage of that, then, > > > since the tests still passed with --zero_copy disabled. > > > > Looks one regression from commit 0a9beafa7c63 ("ublk: refactor auto buffer register in ublk_dispatch_req()") > > Is there a particular issue you see in that commit? I think the issue Looks I overlooked. > is that if UBLK_IO_F_NEED_REG_BUF is set in the ublksrv_io_desc but zc > isn't enabled, the null ublk server will just complete the I/O > immediately. And --auto_zc_fallback isn't supported by any of the > other ublk servers. > > if (auto_zc && !ublk_io_auto_zc_fallback(iod)) > queued = null_queue_auto_zc_io(t, q, tag); > else if (zc) > queued = null_queue_zc_io(t, q, tag); > else { > ublk_complete_io(t, q, tag, iod->nr_sectors << 9); > return 0; > } > > So it looks to me to just be an issue with my kublk change. But ublk_queue_auto_zc_fallback() is broken, so the auto_zc_fallback code path isn't examined actually. Thanks, Ming