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 X-Spam-Level: X-Spam-Status: No, score=-13.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C5723C388F7 for ; Tue, 10 Nov 2020 03:54:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 78CD62080A for ; Tue, 10 Nov 2020 03:54:05 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="r+dBO5WR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732359AbgKJDyC (ORCPT ); Mon, 9 Nov 2020 22:54:02 -0500 Received: from mail.kernel.org ([198.145.29.99]:54590 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732326AbgKJDx7 (ORCPT ); Mon, 9 Nov 2020 22:53:59 -0500 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 0672A207BC; Tue, 10 Nov 2020 03:53:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1604980438; bh=6IoiOFJUKOcUhztuRrXe9uOyWyzAOJU/nq/G7DDNUvE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=r+dBO5WR/M6rUsT3noxVNqk060j4t149FqY5FcewyLvFPQ50VPWJMqZqt91z2GiDM mpIZsnEYfbAnLFn0lnGDGaUBR8QccGk9saATHWs3oKQYBKHgjbiV1zdslQ0Ggjh3B6 kb33pdEBBKNIpHntvpJJsv1/hpX2gxWO3LabYM48= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Keith Busch , "B.L. Jones" , Sasha Levin , linux-nvme@lists.infradead.org Subject: [PATCH AUTOSEL 5.9 28/55] Revert "nvme-pci: remove last_sq_tail" Date: Mon, 9 Nov 2020 22:52:51 -0500 Message-Id: <20201110035318.423757-28-sashal@kernel.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20201110035318.423757-1-sashal@kernel.org> References: <20201110035318.423757-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Keith Busch [ Upstream commit 38210800bf66d7302da1bb5b624ad68638da1562 ] Multiple CPUs may be mapped to the same hctx, allowing mulitple submission contexts to attempt commit_rqs(). We need to verify we're not writing the same doorbell value multiple times since that's a spec violation. Revert commit 54b2fcee1db041a83b52b51752dade6090cf952f. Link: https://bugzilla.redhat.com/show_bug.cgi?id=1878596 Reported-by: "B.L. Jones" Signed-off-by: Keith Busch Signed-off-by: Sasha Levin --- drivers/nvme/host/pci.c | 23 +++++++++++++++++++---- 1 file changed, 19 insertions(+), 4 deletions(-) diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c index 8984796db0c80..a6af96aaa0eb7 100644 --- a/drivers/nvme/host/pci.c +++ b/drivers/nvme/host/pci.c @@ -198,6 +198,7 @@ struct nvme_queue { u32 q_depth; u16 cq_vector; u16 sq_tail; + u16 last_sq_tail; u16 cq_head; u16 qid; u8 cq_phase; @@ -455,11 +456,24 @@ static int nvme_pci_map_queues(struct blk_mq_tag_set *set) return 0; } -static inline void nvme_write_sq_db(struct nvme_queue *nvmeq) +/* + * Write sq tail if we are asked to, or if the next command would wrap. + */ +static inline void nvme_write_sq_db(struct nvme_queue *nvmeq, bool write_sq) { + if (!write_sq) { + u16 next_tail = nvmeq->sq_tail + 1; + + if (next_tail == nvmeq->q_depth) + next_tail = 0; + if (next_tail != nvmeq->last_sq_tail) + return; + } + if (nvme_dbbuf_update_and_check_event(nvmeq->sq_tail, nvmeq->dbbuf_sq_db, nvmeq->dbbuf_sq_ei)) writel(nvmeq->sq_tail, nvmeq->q_db); + nvmeq->last_sq_tail = nvmeq->sq_tail; } /** @@ -476,8 +490,7 @@ static void nvme_submit_cmd(struct nvme_queue *nvmeq, struct nvme_command *cmd, cmd, sizeof(*cmd)); if (++nvmeq->sq_tail == nvmeq->q_depth) nvmeq->sq_tail = 0; - if (write_sq) - nvme_write_sq_db(nvmeq); + nvme_write_sq_db(nvmeq, write_sq); spin_unlock(&nvmeq->sq_lock); } @@ -486,7 +499,8 @@ static void nvme_commit_rqs(struct blk_mq_hw_ctx *hctx) struct nvme_queue *nvmeq = hctx->driver_data; spin_lock(&nvmeq->sq_lock); - nvme_write_sq_db(nvmeq); + if (nvmeq->sq_tail != nvmeq->last_sq_tail) + nvme_write_sq_db(nvmeq, true); spin_unlock(&nvmeq->sq_lock); } @@ -1496,6 +1510,7 @@ static void nvme_init_queue(struct nvme_queue *nvmeq, u16 qid) struct nvme_dev *dev = nvmeq->dev; nvmeq->sq_tail = 0; + nvmeq->last_sq_tail = 0; nvmeq->cq_head = 0; nvmeq->cq_phase = 1; nvmeq->q_db = &dev->dbs[qid * 2 * dev->db_stride]; -- 2.27.0