From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from va-2-42.ptr.blmpb.com (va-2-42.ptr.blmpb.com [209.127.231.42]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D6F78402444 for ; Thu, 30 Jul 2026 10:50:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.127.231.42 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785408648; cv=none; b=lzOg3TI/cRlxoNHkRO3/nOZN8osKk6iIlBJbpSIbCQmkzO9gea5q2Nxm2HPT4FAPQbK4k+z62FZ2HrDmqIWOtm9AbVmy269DntOpXmOX0L4tCN+RfJ2ImvFTJ+/EgfAbnolFJiBqvWdKguFA+4tVLfkFjQW8wSZg7mBuduAxrvo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785408648; c=relaxed/simple; bh=/1sE0Bkf/L3HZLyUENBu3d6MjdTf4BLYpYiR6RIGZu4=; h=From:Message-Id:References:To:Subject:Mime-Version:Date: In-Reply-To:Content-Type; b=X6k7JRomgi4gpWzVOxKsztd+0CKpoHHT27neIZDRZspLwpVyPyhagQZhbo/gLDfIH0vR5Px/Db3fgzXiS6gY4LGhu4wawQYEZLiYy2sfeOTImbt+rViJo9gTEanLox30S30135sGIDjonUr60eL8U6q5U5RX6uyFZZIXUY2QkUs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=fygo.io; spf=pass smtp.mailfrom=fygo.io; dkim=pass (2048-bit key) header.d=fygo-io.20200929.dkim.larksuite.com header.i=@fygo-io.20200929.dkim.larksuite.com header.b=RzyDnktz; arc=none smtp.client-ip=209.127.231.42 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=fygo.io Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=fygo.io Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=fygo-io.20200929.dkim.larksuite.com header.i=@fygo-io.20200929.dkim.larksuite.com header.b="RzyDnktz" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; s=s1; d=fygo-io.20200929.dkim.larksuite.com; t=1785408632; h=from:subject:mime-version:from:date:message-id:subject:to:cc: reply-to:content-type:mime-version:in-reply-to:message-id; bh=O3NayEsacnjJhqbXheSph6Xc0rM/AAUu69minY9rkHg=; b=RzyDnktz0QEOv0W5i/NJO2+myZkdsOBjwxjYI5W7ZkV2P+r8eRBB0A6ezTyAljd8xNIOFZ XlV0+DNACd34yfFMvCIUIIqQNApCMLheQoR/AQpR2E9+fd9DKpvgMhP7yVSZdSJUP9JlUu SWvPcSlCs4inYxNz7NeixE6hsEiBcjhtmkb35qaiPc0g/PrgrJW1GafK7toi0upYBzzjpG jqu4K0dhbF5oDAJVnaVPNXHISgIK62RlykShb/nXsWL8G2YuuOVvpCDOaTfV+tz7GqA3hr noS50FL3K6HR0ESOdZyJW+dRqc0+3hFh2uuEKjtDrYxh16fK59IcZTqPFQJK9w== From: "yu kuai" Message-Id: <07b0887a-e546-4d2f-b261-1fe7adb1d6e0@fygo.io> X-Original-From: yu kuai Received: from [192.168.1.104] ([39.182.0.181]) by smtp.larksuite.com with ESMTPS; Thu, 30 Jul 2026 10:50:30 +0000 References: <20260628142737.1051059-1-abd.masalkhi@gmail.com> Reply-To: yukuai@fygo.io To: "Abd-Alrhman Masalkhi" , , , , , , , , "yu kuai" Subject: Re: [PATCH] md: remove REQ_NOWAIT support Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Lms-Return-Path: User-Agent: Mozilla Thunderbird Content-Transfer-Encoding: quoted-printable Date: Thu, 30 Jul 2026 18:50:26 +0800 In-Reply-To: <20260628142737.1051059-1-abd.masalkhi@gmail.com> Content-Type: text/plain; charset=UTF-8 Hi, =E5=9C=A8 2026/6/28 22:27, Abd-Alrhman Masalkhi =E5=86=99=E9=81=93: > REQ_NOWAIT support in md is fundamentally incomplete. While reads can > avoid some blocking paths, write requests can still encounter cases > where one mirror succeeds while another returns -EAGAIN. At that point > md cannot distinguish queue pressure from a real device failure, so it > can neither record a bad block nor safely retry the write without > REQ_NOWAIT, leaving mirrors with divergent data. > > Rather than continue advertising REQ_NOWAIT support that cannot be > implemented correctly, remove it from md and its raid personalities. > This simplifies the waiting paths and avoids exposing incorrect > non-blocking semantics. > > Fixes: bf2c411bb1cf ("md: raid456 add nowait support") > Fixes: c9aa889b035f ("md: raid10 add nowait support") > Fixes: 5aa705039c4f ("md: raid1 add nowait support") > Fixes: f51d46d0e7cb ("md: add support for REQ_NOWAIT") > Suggested-by: Yu Kuai > Signed-off-by: Abd-Alrhman Masalkhi > --- > drivers/md/md-bitmap.c | 9 +--- > drivers/md/md-bitmap.h | 2 +- > drivers/md/md-llbitmap.c | 10 +---- > drivers/md/md.c | 15 ++----- > drivers/md/raid1-10.c | 8 ++-- > drivers/md/raid1.c | 91 +++++++++------------------------------- > drivers/md/raid10.c | 80 +++++++++-------------------------- > drivers/md/raid5.c | 13 ------ > 8 files changed, 51 insertions(+), 177 deletions(-) Applied to md-7.3 with a few changes, please check: md: remove REQ_NOWAIT support from raid1/10/456 -=20 kernel/git/mdraid/linux.git - song's fork of linux.git - rebase raid1/raid10 with latest code; - keep nowait for raid0/linear; - keep nowait for md_handle_request, as raid0/linear will need it; --=20 Thanks, Kuai