From patchwork Thu Apr 20 10:11:16 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Avri Altman X-Patchwork-Id: 13218430 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D8429C77B72 for ; Thu, 20 Apr 2023 10:14:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234605AbjDTKOd (ORCPT ); Thu, 20 Apr 2023 06:14:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54220 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234469AbjDTKNt (ORCPT ); Thu, 20 Apr 2023 06:13:49 -0400 Received: from esa4.hgst.iphmx.com (esa4.hgst.iphmx.com [216.71.154.42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5132730EE; Thu, 20 Apr 2023 03:11:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=wdc.com; i=@wdc.com; q=dns/txt; s=dkim.wdc.com; t=1681985506; x=1713521506; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=IqX1KGc2zqXc+B1++YmyPlNP2lpj621/TtGNfPcNhxc=; b=JPhVkVGuwPX+vXRa39++itG3XazcHzzTsEjUiM2eNxmwXZJRDWcvZpna 7e78BZU6faZ5uYTSgS9Z9NMmFJJ1oZcIB+Y81g2BKd7utaM33z6qOnEv2 c+f+xGVl51XvWTukHibZ/SDt7ymWA0yBRALYiyRmwwsAfqVDrXD6vhexB zysv75miOd+uDbe5Dki0o99KoOjPap4ZwVeR/SgsttUK3DhfKajhfOdxn b36gN1KTP97ROvOi2Dg8SBXx4Nzh3cFpYSCrU0DRkGlSNkiTpeeo8U9Mx q5ckui+wnB8eU2r/Hh3QCUvHj69qC+uAF5hQ19SnNJWkT1qYgPa/VI1qd g==; X-IronPort-AV: E=Sophos;i="5.99,212,1677513600"; d="scan'208";a="227179734" Received: from uls-op-cesaip02.wdc.com (HELO uls-op-cesaep02.wdc.com) ([199.255.45.15]) by ob1.hgst.iphmx.com with ESMTP; 20 Apr 2023 18:11:45 +0800 IronPort-SDR: rdE0lWEq9+TofNrozWjk06ulUBQ8VgH6Jg0K2Ekbeom1b9UFskhNm1kpxbmVLLOKdw8aCXqNoD fFh3Znqn0Xi5x45TYRRj5fkQi7sq6i51K9mSoyJOQJUAl05ULWLw32j2ouqPHvhQHGLUcx/M5V 3tjCo1WICe8dP0YSZjJwFC0VHXn+FJjNvzImO9jpfKBGcWQtsnLM37D+MZc+G8qKoEm0aMFXL/ NX5MoHHq0bkWsjC30u5rrAviiOiSkm9fBJehvu/4VfqvvGDbJ15Rwwy2OAI7sIzZ83VjjdQaU6 9K8= Received: from uls-op-cesaip02.wdc.com ([10.248.3.37]) by uls-op-cesaep02.wdc.com with ESMTP/TLS/ECDHE-RSA-AES128-GCM-SHA256; 20 Apr 2023 02:21:47 -0700 IronPort-SDR: ORsds7CtjxmB5wYxkvbO2BbKRBatGs09seFBUNJYG1SyomkUvbUDcKdrEjOtxAATob/67q+1Ww 5kB1UgCufxRzQa8oDELgTy7DFmlpP+LWlQSRB6XzPFj5bm43lMxtFchbeZ7xDsT06ifPwT9xaK EffgDeF727Wi38xD++31niqoaO/IupmJe7nqsyEAT88DTmqJu7hiH6OAr2P/sa6ljxbzhWukBr UR6i9MtV8T+MsTbFdk8Enelh/yFFuCt8ZKYGkVZpENznXa/C/HH9Cs53QILh2sl/cQGeJkJamE XDM= WDCIronportException: Internal Received: from bxygm33.ad.shared ([10.45.31.229]) by uls-op-cesaip02.wdc.com with ESMTP; 20 Apr 2023 03:11:43 -0700 From: Avri Altman To: "James E . J . Bottomley" , "Martin K . Petersen" Cc: Asutosh Das , quic_cang@quicinc.com, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, Johannes Thumshirn , Bart Van Assche , John Garry , Avri Altman , Johannes Thumshirn Subject: [PATCH v3] scsi: ufs: mcq: Limit the amount of inflight requests Date: Thu, 20 Apr 2023 13:11:16 +0300 Message-Id: <20230420101116.173-1-avri.altman@wdc.com> X-Mailer: git-send-email 2.40.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org in UFS, each request is designated via the triplet . In UFS4.0 the Initiator ID field is 8 bits wide, comprised of the EXT_IID and IID fields. Together with the task tag (single byte), they limit the driver's hw queues capacity. The purpose of this patch is to document the ufs spec restrictions. practically, it impose no functional change because a) the current hw supports much less (merely 64 requests), and b) since shost->host_tagset is set - then the number of inflight IOs is limited by just the HW queue depth. --- v2 -> v3: fix smatch warnings (Dan Carpenter) elaborate commit log (John Garry) v1 -> v2: Attend Johannes's and Bart's comments Reviewed-by: Johannes Thumshirn Signed-off-by: Avri Altman --- drivers/ufs/core/ufshcd.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c index 03c47f9a2750..9cebec6be35c 100644 --- a/drivers/ufs/core/ufshcd.c +++ b/drivers/ufs/core/ufshcd.c @@ -8468,6 +8468,12 @@ static int ufshcd_alloc_mcq(struct ufs_hba *hba) if (ret) goto err; + if (hba->nutrs * hba->nr_hw_queues > SZ_64K - 1) { + dev_info(hba->dev, "there can be at most 64K inflight requests\n"); + ret = -EINVAL; + goto err; + } + /* * Previously allocated memory for nutrs may not be enough in MCQ mode. * Number of supported tags in MCQ mode may be larger than SDB mode.