From patchwork Sat Mar 8 16:14:52 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ming Lei X-Patchwork-Id: 14007577 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (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 C24E6383A2 for ; Sat, 8 Mar 2025 16:15:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741450535; cv=none; b=IrFgMtOZNTFNzjIC8GeYKYO+/b5jozZ0L9y/3I0Kc+gITZhpCVIPSOAuP9jiT3TOL3z+2ETWG3Bn8z5hnzMDemynYkoua/SFCQ+O7jZ+fj6C8w7c0xXE9a03JBfZc8c27FKRO1Qka36Nj7buAp1EJoOBl3PRWOTiJSqc+ToFDZM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741450535; c=relaxed/simple; bh=u5/4nj2ac7HVWMRc5crLzT65h3we0ohrKVZmSnCOre4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=VeRoixY0pC6dTt4ZciGLeBjM6b8XKWI9ax1kwnNcc/trdKAWnOSyWke7jXVq5pL5ZNdigg4O31jW/mowwrFWoECF9rhGY4PwFYSKmzXEpIoOFg3MX9XkjGwTsYqijhfc4uCJjFKz5CVn5ypp+UpR6EqqEMlcKsZ5KHpAMIVmKVw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none 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=ZiwGK//s; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none 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="ZiwGK//s" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1741450532; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=8denhFmEdN5tN08SrQHZAgAryJrIovxDrRi5iaFG/aE=; b=ZiwGK//s86ZKze62kkbf5R19MVUzAJ5vIbu6SJr2A5F73J4OfYQdFKwAqyvbQzb5xvl/Om plAU6jlUXyUu2+lEkrAU6fx73GC82UIGE/H5c53jLR7D+UeF8medyzUarj4lFaaCu9l0X5 6N6xfSS8/ZmhykjeojfVlzwXmuQVPis= Received: from mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-484-BrFzYQNAMAyqXmsDrUnQbw-1; Sat, 08 Mar 2025 11:15:27 -0500 X-MC-Unique: BrFzYQNAMAyqXmsDrUnQbw-1 X-Mimecast-MFC-AGG-ID: BrFzYQNAMAyqXmsDrUnQbw_1741450526 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (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-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id CEC8C19560AB; Sat, 8 Mar 2025 16:15:25 +0000 (UTC) Received: from localhost (unknown [10.72.120.5]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id B58D9300019E; Sat, 8 Mar 2025 16:15:23 +0000 (UTC) From: Ming Lei To: Jens Axboe , linux-block@vger.kernel.org Cc: Ming Lei Subject: [PATCH] loop: fallback to buffered IO in case of dio submission failure Date: Sun, 9 Mar 2025 00:14:52 +0800 Message-ID: <20250308161504.1639157-3-ming.lei@redhat.com> In-Reply-To: <20250308161504.1639157-1-ming.lei@redhat.com> References: <20250308161504.1639157-1-ming.lei@redhat.com> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Signed-off-by: Ming Lei --- drivers/block/loop.c | 21 ++++++++++++++++----- 1 file changed, 16 insertions(+), 5 deletions(-) diff --git a/drivers/block/loop.c b/drivers/block/loop.c index 7bf4686af774..2fa15933860d 100644 --- a/drivers/block/loop.c +++ b/drivers/block/loop.c @@ -562,6 +562,14 @@ static void lo_rw_aio_complete(struct kiocb *iocb, long ret, long ret2) lo_rw_aio_do_completion(cmd); } +static inline int lo_call_backing_rw_iter(struct file *file, + struct kiocb *iocb, struct iov_iter *iter, bool rw) +{ + if (rw == WRITE) + return call_write_iter(file, iocb, iter); + return call_read_iter(file, iocb, iter); +} + static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, loff_t pos, bool rw) { @@ -619,15 +627,18 @@ static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd, cmd->iocb.ki_flags = IOCB_DIRECT; cmd->iocb.ki_ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, 0); - if (rw == WRITE) - ret = call_write_iter(file, &cmd->iocb, &iter); - else - ret = call_read_iter(file, &cmd->iocb, &iter); + ret = lo_call_backing_rw_iter(file, &cmd->iocb, &iter, rw); lo_rw_aio_do_completion(cmd); - if (ret != -EIOCBQUEUED) + if (ret >= 0) { cmd->iocb.ki_complete(&cmd->iocb, ret, 0); + } else if (ret != -EIOCBQUEUED) { + /* fallback to buffered IO */ + cmd->iocb.ki_flags = 0; + cmd->ret = lo_call_backing_rw_iter(file, &cmd->iocb, &iter, rw); + lo_rw_aio_do_completion(cmd); + } return 0; }