From patchwork Tue Oct 22 07:43:16 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Avri Altman X-Patchwork-Id: 837758 Received: from esa1.hgst.iphmx.com (esa1.hgst.iphmx.com [68.232.141.245]) (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 1499414A4F0; Tue, 22 Oct 2024 07:45:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=68.232.141.245 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729583129; cv=none; b=BTZr/bn3Vj4u5iTdD5HZvrdr/DxrcCusCNsgXotQZHaK0CiaC1yHJmZbgKSJyHFNFcrrVv5pfDVt5W2wazJuIVDAPxp1WIzhTjtEfysx0F5N7v65QG7huTmQId/aHE8ocVJBOQ53T7uVX1yqohHSIseCqm/DXRPNY+ZaLH6QQ44= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729583129; c=relaxed/simple; bh=P+sigj3NdXbec5NDcpWfBeJ9hag3FsGgKYoz1DFkHtw=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=eEgRKwrRGfpVBfmTM2PH8tsK/t90B5enthCfkcexoX5dUsrfA0JL+D+r4i7QNDEQ/32Hx8RlFLk7eL/LgdC2VHjNbayW+ZDYVybXnKxi66NyUj2sSVRs0dciiynxYxkjD8UWD75/iQgrTwnq1OemH9gbR7UHzXXY3t5VWJq5Tko= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=wdc.com; spf=pass smtp.mailfrom=wdc.com; dkim=pass (2048-bit key) header.d=wdc.com header.i=@wdc.com header.b=n68CvutR; arc=none smtp.client-ip=68.232.141.245 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=wdc.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=wdc.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=wdc.com header.i=@wdc.com header.b="n68CvutR" DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=wdc.com; i=@wdc.com; q=dns/txt; s=dkim.wdc.com; t=1729583127; x=1761119127; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=P+sigj3NdXbec5NDcpWfBeJ9hag3FsGgKYoz1DFkHtw=; b=n68CvutRB9K5VDpT5jp9RNJgOAMJ1ukc54Pg8NrMrXaI4Tpha75qyure eGrz1BZVOYxQJv4v705vV+pcbLH065loLWhI9E5OKDhE6JW6Lz6fZptV1 Hj/2eIgRibeH0oz9GcwFTfRJciLlpDRvoNvxejAMahYdszl13HzzZKohv 4Msljthz4clRPiNlTZGaee3ZkmPbvzznmSno/IejSu2LkuiMQ3y/sTAEH CLNGnnKZBtVebsRwv0BxJ6mbXupxhMdiWa8+nCOzR+Qu7hYkFSUao/K/o BhbVi7ACJZAIBL694FaF/lTtdiyy8T6hrnzZfP5TMMos/quY7Vo+X2xnW Q==; X-CSE-ConnectionGUID: 3zbmKEDRS6ebS4td2hEx2A== X-CSE-MsgGUID: NxY1sKxRS06oQh/uDMpd1g== X-IronPort-AV: E=Sophos;i="6.11,222,1725292800"; d="scan'208";a="30533951" Received: from h199-255-45-15.hgst.com (HELO uls-op-cesaep02.wdc.com) ([199.255.45.15]) by ob1.hgst.iphmx.com with ESMTP; 22 Oct 2024 15:45:27 +0800 IronPort-SDR: 671749a7_If94Cuvg/ILrXCfjOUoEf8xqOCIcyTOjN/7T3KIfYNfi62C mIlkSs/6DXEzlFFRU7VHjXrZpvpe9BOQeD3XVGw== Received: from uls-op-cesaip01.wdc.com ([10.248.3.36]) by uls-op-cesaep02.wdc.com with ESMTP/TLS/ECDHE-RSA-AES128-GCM-SHA256; 21 Oct 2024 23:43:52 -0700 WDCIronportException: Internal Received: from avri-office.ad.shared (HELO avri-office.sdcorp.global.sandisk.com) ([10.45.31.142]) by uls-op-cesaip01.wdc.com with ESMTP/TLS/ECDHE-RSA-AES128-GCM-SHA256; 22 Oct 2024 00:45:25 -0700 From: Avri Altman To: "Martin K . Petersen" Cc: linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, Bart Van Assche , Avri Altman Subject: [PATCH v2 0/3] Untie the host lock entanglement - part 1 Date: Tue, 22 Oct 2024 10:43:16 +0300 Message-Id: <20241022074319.512127-1-avri.altman@wdc.com> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 While trying to simplify the ufs core driver with the guard() macro [1], Bart made note of the abuse of the scsi host lock in the ufs driver. Indeed, the host lock is deeply entangled in various flows across the driver, as if it was some occasional default synchronization mean. Here is the first part of defusing it, remove some of those calls around host registers accesses, which needs no protection. Doing this in phases seems like a reasonable approach, given the myriad use of the host lock. Changes compared to v1: - get rid of redundant locking (Bart) - leave out the HCE register [1] https://lore.kernel.org/linux-scsi/0b031b8f-c07c-42ef-af93-7336439d3c37@acm.org/ Avri Altman (3): scsi: ufs: core: Remove redundant host_lock calls around UTMRLDBR. scsi: ufs: core: Remove redundant host_lock calls around UTMRLCLR scsi: ufs: core: Remove redundant host_lock calls around UTRLCLR. drivers/ufs/core/ufshcd.c | 26 +++++++++----------------- 1 file changed, 9 insertions(+), 17 deletions(-)