From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 54F2AC4332F for ; Thu, 14 Dec 2023 22:50:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=K9LXU3is+IJ/FA2WLEo3Morjs3r0CReNzWjYTp8T0b0=; b=qORqR0x5fCb2Tn3D4MAh00yGI6 Rg7sDuvKWEExmD6GE1AmT2BJt7Pborg0rvwAhbpJjNXKbStNghAqiby/w/G9OMNZtAO6xz3AXivB7 4ptv3Jdz1AxmsD+l8bdCpT/RDg0OC5R04dk0DdADtqJy2aCzfi7uawhxq6LtMyKAsJf/wuCEv3n6Q luegmJVDp10Cj7pXWMvel3EXGiBdlkM39zYoBuPeIuDLpIzAgphq6WaY66QHYaTpIHeyQy9X7/sOF Byp9Mmco1ZI2Sm7HVW/Xu/hRpoMsJUrEERLyTIJswfA5AWAdW5GHLkBXFccRuIsCXN+rJSWdyOMbs rHtMtduQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1rDuWp-001UXI-2L; Thu, 14 Dec 2023 22:50:03 +0000 Received: from sin.source.kernel.org ([2604:1380:40e1:4800::1]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1rDuWl-001UV0-1u for linux-nvme@lists.infradead.org; Thu, 14 Dec 2023 22:50:02 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sin.source.kernel.org (Postfix) with ESMTP id 1D454CE223E; Thu, 14 Dec 2023 22:49:57 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id EDAB2C433C8; Thu, 14 Dec 2023 22:49:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1702594196; bh=wyU0Fm9SOSd3j+OhfeqLs4fQpW/XmDPEDEOLYCp/Gm4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=MJB0ONvX8EKumio3sThaYHRwmtmP2Nisin3Y6NePuOHFSpcTnDVi9ma/0pO3dbX7q cThXQnhgCOi2x6GNbRNo47kgjdWC/S88kStmm3qAaqzh2igCQ5qwFTYR5JrLoaTg2p ln3MUEgbSSzTUqDvlldNBE1UMZUQnXifh7zQS0nm+e6mRcBfguHkuaWJXuoV9ki4J0 m3DE3wSzHObtCZFRQcY4AAvSzIoB32YjujIKysKqPWN/EPsYwOG+Ff6EQFJsHqzxwH tavM6A9hZ7bSpVOiQRn2OnP17X4B7ts+v44hamBk1enwobcjRafrMTS9+WQxLKVY0p BS/u6vwYC/ADw== Date: Thu, 14 Dec 2023 14:49:54 -0800 From: Keith Busch To: Niklas Cassel Cc: "linux-nvme@lists.infradead.org" , Kamaljit Singh , Shinichiro Kawasaki , Damien Le Moal Subject: Re: parallel nvme format Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231214_144959_970239_CB6A54E9 X-CRM114-Status: GOOD ( 17.89 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Thu, Dec 14, 2023 at 09:21:28PM +0000, Niklas Cassel wrote: > Perhaps we could introduce a new bit, NVME_CTRL_NEEDS_SCAN or similar? > (That gets cleared by nvme_scan_work(), after a scan has been performed.) Good point. Updated patch below. > I guess for format command specifically, we already have > NVME_AER_NOTICE_NS_CHANGED, but that seems to be cleared before by > nvme_scan_work() before the mutex is acquired. The clearing should just re-arm the controller to send the AER again if any other namespace changes. But we can't really depend on the AER anyway. > And I'm not sure if all command that have > effects & (NVME_CMD_EFFECTS_NIC | NVME_CMD_EFFECTS_NCC) > set will trigger a NVME_AER_NOTICE_NS_CHANGED AEN. We have the "known_effects" for the format command to ensure the driver will always request a rescan on a format no matter what a controller reports, but yeah, the format could be followed up by another command with NVME_CMD_EFFECTS_CSE_MASK set without NIC/NCC, so definitely need to retain the need to restart the scan. --- diff --git a/drivers/nvme/host/core.c b/drivers/nvme/host/core.c index 590cd4f097c22..0b062a2268447 100644 --- a/drivers/nvme/host/core.c +++ b/drivers/nvme/host/core.c @@ -1120,6 +1120,8 @@ u32 nvme_passthru_start(struct nvme_ctrl *ctrl, struct nvme_ns *ns, u8 opcode) nvme_start_freeze(ctrl); nvme_wait_freeze(ctrl); } + if (effects & (NVME_CMD_EFFECTS_NIC | NVME_CMD_EFFECTS_NCC)) + set_bit(NVME_CTRL_NEEDS_RESCAN, &ctrl->flags); return effects; } EXPORT_SYMBOL_NS_GPL(nvme_passthru_start, NVME_TARGET_PASSTHRU); @@ -1140,7 +1142,7 @@ void nvme_passthru_end(struct nvme_ctrl *ctrl, struct nvme_ns *ns, u32 effects, "controller capabilities changed, reset may be required to take effect.\n"); } } - if (effects & (NVME_CMD_EFFECTS_NIC | NVME_CMD_EFFECTS_NCC)) { + if (test_bit(NVME_CTRL_NEEDS_RESCAN, &ctrl->flags)) { nvme_queue_scan(ctrl); flush_work(&ctrl->scan_work); } @@ -3945,7 +3947,14 @@ static void nvme_scan_work(struct work_struct *work) nvme_clear_changed_ns_log(ctrl); } - mutex_lock(&ctrl->scan_lock); + /* + * Failure to acquire scan_lock means another thread will requeue this + * work shortly + */ + if (!mutex_trylock(&ctrl->scan_lock)) + return; + + clear_bit(NVME_CTRL_NEEDS_RESCAN, &ctrl->flags); if (nvme_ctrl_limited_cns(ctrl)) { nvme_scan_ns_sequential(ctrl); } else { diff --git a/drivers/nvme/host/nvme.h b/drivers/nvme/host/nvme.h index 39a90b7cb1254..79a71b6ae64fe 100644 --- a/drivers/nvme/host/nvme.h +++ b/drivers/nvme/host/nvme.h @@ -251,6 +251,7 @@ enum nvme_ctrl_flags { NVME_CTRL_STOPPED = 3, NVME_CTRL_SKIP_ID_CNS_CS = 4, NVME_CTRL_DIRTY_CAPABILITY = 5, + NVME_CTRL_NEEDS_RESCAN = 6, }; struct nvme_ctrl { --