{"id":2235186,"url":"http://patchwork.ozlabs.org/api/1.2/covers/2235186/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-ide/cover/20260508195051.188207-4-cassel@kernel.org/","project":{"id":13,"url":"http://patchwork.ozlabs.org/api/1.2/projects/13/?format=json","name":"Linux IDE development","link_name":"linux-ide","list_id":"linux-ide.vger.kernel.org","list_email":"linux-ide@vger.kernel.org","web_url":null,"scm_url":null,"webscm_url":null,"list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<20260508195051.188207-4-cassel@kernel.org>","list_archive_url":null,"date":"2026-05-08T19:50:51","name":"[v3,0/2] ata: fix deferred QC handling for port multipliers","submitter":{"id":87751,"url":"http://patchwork.ozlabs.org/api/1.2/people/87751/?format=json","name":"Niklas Cassel","email":"cassel@kernel.org"},"mbox":"http://patchwork.ozlabs.org/project/linux-ide/cover/20260508195051.188207-4-cassel@kernel.org/mbox/","series":[{"id":503439,"url":"http://patchwork.ozlabs.org/api/1.2/series/503439/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-ide/list/?series=503439","date":"2026-05-08T19:50:51","name":"ata: fix deferred QC handling for port multipliers","version":3,"mbox":"http://patchwork.ozlabs.org/series/503439/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/covers/2235186/comments/","headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-ide@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256\n header.s=k20201202 header.b=TxYfdv3B;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=172.234.253.10; helo=sea.lore.kernel.org;\n envelope-from=linux-ide+bounces-5700-incoming=patchwork.ozlabs.org@vger.kernel.org;\n receiver=patchwork.ozlabs.org)","smtp.subspace.kernel.org;\n\tdkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org\n header.b=\"TxYfdv3B\"","smtp.subspace.kernel.org;\n arc=none smtp.client-ip=10.30.226.201"],"Received":["from sea.lore.kernel.org (sea.lore.kernel.org [172.234.253.10])\n\t(using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n\t key-exchange x25519)\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4gC09X57Csz1yCg\n\tfor ; Sat, 09 May 2026 05:51:12 +1000 (AEST)","from smtp.subspace.kernel.org (conduit.subspace.kernel.org\n [100.90.174.1])\n\tby sea.lore.kernel.org (Postfix) with ESMTP id EB762301CF86\n\tfor ; Fri, 8 May 2026 19:51:10 +0000 (UTC)","from localhost.localdomain (localhost.localdomain [127.0.0.1])\n\tby smtp.subspace.kernel.org (Postfix) with ESMTP id 5BC5F351C20;\n\tFri, 8 May 2026 19:51:10 +0000 (UTC)","from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org\n [10.30.226.201])\n\t(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby smtp.subspace.kernel.org (Postfix) with ESMTPS id 3914C34DB4A\n\tfor ; Fri, 8 May 2026 19:51:10 +0000 (UTC)","by smtp.kernel.org (Postfix) with ESMTPSA id 88AFDC2BCB0;\n\tFri, 8 May 2026 19:51:08 +0000 (UTC)"],"ARC-Seal":"i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116;\n\tt=1778269870; cv=none;\n b=GNMIeeN5zYgPJ2OZWS9g3e42ZsFmy2Sg36i06dNc/Zrbnz/rqV8ieZU/PK73fBYUvmV5ZUAg2554/mqQmcdKi6EWnTtUvqNnnNP2Ku3MvCL84puO3IK7kkCkj2aIKx8lzwNbsXHECOTfbjZCdNZdR232q1+cznUxM85xYX/SxSo=","ARC-Message-Signature":"i=1; a=rsa-sha256; d=subspace.kernel.org;\n\ts=arc-20240116; t=1778269870; c=relaxed/simple;\n\tbh=rYsTj0M1yvVHhMG8UlQsWNxYUfAz08kCQBbBRkaHjfg=;\n\th=From:To:Cc:Subject:Date:Message-ID:MIME-Version;\n b=MaYCI85Jbl11ywY4/6EXmtxrfnyv9Rx7L58qEu7CSIIb2JCkyULSgR3Tk7bT9l+d12Jr2dfWoo4dg4r8LftpxEG/WJ9eHp3LgaGc7TjjSxvwAewBGRWVTW9MSUWneTH0/SYKHQMLN6UxMXbVGEoenycMs788bnNgQRO7RpPGgMc=","ARC-Authentication-Results":"i=1; smtp.subspace.kernel.org;\n dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org\n header.b=TxYfdv3B; arc=none smtp.client-ip=10.30.226.201","DKIM-Signature":"v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org;\n\ts=k20201202; t=1778269870;\n\tbh=rYsTj0M1yvVHhMG8UlQsWNxYUfAz08kCQBbBRkaHjfg=;\n\th=From:To:Cc:Subject:Date:From;\n\tb=TxYfdv3BIwqC52E/B5q1Z3FGds0JeGDdZSdVvPvwBpC9Vu57eIXg679LbvqhrXiAj\n\t Vq9GRJg2taSt0vYA+7xgpj/V0pKvfQaywN5IITFzf91tOGrW+HC4YP3U2amlLxjIOt\n\t IiZby+yIirCZXD2OkVOFmZEPUdR9blYbvCuSaSLUfRtNc6bV2Rz2vTqj2zl6PJ/6Ul\n\t HqEbpjdSnuQgfGEEuVGyCBlsDXLekej+ddjkijgNu/On7r38GYyC24Bk0DVuqtoLKd\n\t XyEaOSXG/fNSZ8WY23TJjXOZwsbiSSVIGqGdCwjH3d4OG17EFlH+MgYLTZNCMF1ZBr\n\t dyzc79rCKzqfw==","From":"Niklas Cassel ","To":"Tommy Kelly ,\n\tDamien Le Moal ,\n\tNiklas Cassel ,\n\tJohn Garry ,\n\t\"Martin K. Petersen\" ","Cc":"linux-ide@vger.kernel.org","Subject":"[PATCH v3 0/2] ata: fix deferred QC handling for port multipliers","Date":"Fri, 8 May 2026 21:50:51 +0200","Message-ID":"<20260508195051.188207-4-cassel@kernel.org>","X-Mailer":"git-send-email 2.54.0","Precedence":"bulk","X-Mailing-List":"linux-ide@vger.kernel.org","List-Id":"","List-Subscribe":"","List-Unsubscribe":"","MIME-Version":"1.0","X-Developer-Signature":"v=1; a=openpgp-sha256; l=1492; i=cassel@kernel.org;\n h=from:subject; bh=rYsTj0M1yvVHhMG8UlQsWNxYUfAz08kCQBbBRkaHjfg=;\n b=owGbwMvMwCV2MsVw8cxjvkWMp9WSGDL/2c1e2V9QrMYdu+LPj6I4rd4m3xNdz5MFdL48PnTrw\n sbtW3zud5SyMIhxMciKKbL4/nDZX9ztPuW44h0bmDmsTCBDGLg4BWAiumcZ/kpunhR7s9nq4Ckl\n LZWkvGnWZ+7MudG5+86ZHaEH7Zg2LZVhZLicxhN+7Emybfvf5pl7WloVuU0EzKxnXcl6Xbj40PS\n ApewA","X-Developer-Key":"i=cassel@kernel.org; a=openpgp;\n fpr=5ADE635C0E631CBBD5BE065A352FE6582ED9B5DA","Content-Transfer-Encoding":"8bit"},"content":"Hello all,\n\nTommy Kelly reported a regression with PMP that use CBS:\nhttps://lore.kernel.org/linux-ide/ce09cc21-a8e9-4845-b205-35411e22fba9@tkel.ly/\n\nIt turns out that the ap->excl_link logic used for PMP that use CBS is\nincompatible with the deferred qc issuing via a workqueue.\nThis is fixed in patch 1/2.\n\nWhile looking at the code, it turns out that the deferred qc issuing via\nworkqueue is misdesigned. It assumed that we can't mix NCQ and non-NCQ\ncommands on the same port. The limitation is that you can not mix NCQ and\nnon-NCQ commands on the same drive. However, with a PMP with FBS, you can\nissue (mixed NCQ and non-NCQ commands) to the different drives. Thus, move\nthe saved deferred QC from struct ata_port to struct ata_link. This is\nfixed in patch 2/2.\n\n\nChanges since v1:\n-Avoid a local variable in sata_pmp_qc_defer_cmd_switch(), call\n ata_std_qc_defer(qc) inside the switch() directly instead.\n-Fix a typo, such that the the code actually compiles... Sorry for that.\n\n\nNiklas Cassel (2):\n ata: libata-scsi: do not use the deferred QC feature on PMPs with CBS\n ata: libata-scsi: do not needlessly defer commands when using PMP with\n FBS\n\n drivers/ata/libata-core.c | 16 ++++---\n drivers/ata/libata-eh.c | 8 ++--\n drivers/ata/libata-pmp.c | 26 +++++++++--\n drivers/ata/libata-scsi.c | 95 ++++++++++++++++++++++++---------------\n include/linux/libata.h | 8 ++--\n 5 files changed, 101 insertions(+), 52 deletions(-)"}