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{ "id": 2235181, "url": "http://patchwork.ozlabs.org/api/1.2/covers/2235181/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linux-ide/cover/20260508193240.176735-4-cassel@kernel.org/", "project": { "id": 13, "url": "http://patchwork.ozlabs.org/api/1.2/projects/13/?format=api", "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": "<20260508193240.176735-4-cassel@kernel.org>", "list_archive_url": null, "date": "2026-05-08T19:32:40", "name": "[v2,0/2] ata: fix deferred QC handling for port multipliers", "submitter": { "id": 87751, "url": "http://patchwork.ozlabs.org/api/1.2/people/87751/?format=api", "name": "Niklas Cassel", "email": "cassel@kernel.org" }, "mbox": "http://patchwork.ozlabs.org/project/linux-ide/cover/20260508193240.176735-4-cassel@kernel.org/mbox/", "series": [ { "id": 503436, "url": "http://patchwork.ozlabs.org/api/1.2/series/503436/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linux-ide/list/?series=503436", "date": "2026-05-08T19:32:41", "name": "ata: fix deferred QC handling for port multipliers", "version": 2, "mbox": "http://patchwork.ozlabs.org/series/503436/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/covers/2235181/comments/", "headers": { "Return-Path": "\n <linux-ide+bounces-5697-incoming=patchwork.ozlabs.org@vger.kernel.org>", "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=KwFynRPq;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c15:e001:75::12fc:5321; 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Fri, 8 May 2026 19:32:59 +0000 (UTC)", "by smtp.kernel.org (Postfix) with ESMTPSA id BF875C2BCB0;\n\tFri, 8 May 2026 19:32:57 +0000 (UTC)" ], "ARC-Seal": "i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116;\n\tt=1778268779; cv=none;\n b=FRAaG9/A0auBOk1apoRY+DL5CnukdGQh4OhaOHnD/Xz3U3vljpedjEd5TKzFg1h2XkLXZLzv+HFNQnRI29nfgA+FssxMJLLLqt3hM8vFc4o75EaKYiH8KPrjNlrDXfEdC2qdvSDfIuFgiXQNyzaJEkvZ4FesQxPuh66q24BQwRk=", "ARC-Message-Signature": "i=1; a=rsa-sha256; d=subspace.kernel.org;\n\ts=arc-20240116; t=1778268779; c=relaxed/simple;\n\tbh=ChDGXEmlBWdk7aNqrsHjo2rw2rZmfJDfEqJv/ZCe0vo=;\n\th=From:To:Cc:Subject:Date:Message-ID:MIME-Version;\n b=VQfPI3TzYx/Mf/JtXbxNfia9/DLtJH8riP4f08S4wLxbZk8oWTOU6XEDodZ8uzbxqqjUFael5mMdG/5XBHo9QA5ZKFWRW1ABL2f/e1H0KontL2fUiASvY434W2nWtJx70TKMniqLhK2BHyMRNXYLoZvQ4yiVjW3aVPDxpN7L7Hc=", "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=KwFynRPq; 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=1778268779;\n\tbh=ChDGXEmlBWdk7aNqrsHjo2rw2rZmfJDfEqJv/ZCe0vo=;\n\th=From:To:Cc:Subject:Date:From;\n\tb=KwFynRPqool5Q3CQBvUqZiXbPM5lDqFVYoZT2Z4G39WaMrofoeKeiOfL/oMgeQs++\n\t Xril4AjsgZgZxoRZMe5R7/7zKFQt0fE8fC+iia54dAhsBVRQh5ZUEQ0qjhZwlsK7zN\n\t WPkhgq09R5uK3aX8bajN4awAzsH3rGhDPDZnscfrNeEesgF+3RtnkgW1UFzAayANhD\n\t bwKPVXsJiiVrM4p5LX8d3rZ2q/52Hxgf5yClB2UEovWhKIZ59fN7bn5pxjDOvIPTh7\n\t 9T4VuftRtjBAC6G9QZhvxIXqJDtLLkyMANu8DPQxPM9Bsan+Ia4tKsmwBVxr0c7FBc\n\t 7zotWAU3s+fSw==", "From": "Niklas Cassel <cassel@kernel.org>", "To": "Tommy Kelly <linux@tkel.ly>,\n\tDamien Le Moal <dlemoal@kernel.org>,\n\tNiklas Cassel <cassel@kernel.org>,\n\t\"Martin K. Petersen\" <martin.petersen@oracle.com>,\n\tJohn Garry <john.g.garry@oracle.com>", "Cc": "linux-ide@vger.kernel.org", "Subject": "[PATCH v2 0/2] ata: fix deferred QC handling for port multipliers", "Date": "Fri, 8 May 2026 21:32:40 +0200", "Message-ID": "<20260508193240.176735-4-cassel@kernel.org>", "X-Mailer": "git-send-email 2.54.0", "Precedence": "bulk", "X-Mailing-List": "linux-ide@vger.kernel.org", "List-Id": "<linux-ide.vger.kernel.org>", "List-Subscribe": "<mailto:linux-ide+subscribe@vger.kernel.org>", "List-Unsubscribe": "<mailto:linux-ide+unsubscribe@vger.kernel.org>", "MIME-Version": "1.0", "X-Developer-Signature": "v=1; a=openpgp-sha256; l=1572; i=cassel@kernel.org;\n h=from:subject; bh=ChDGXEmlBWdk7aNqrsHjo2rw2rZmfJDfEqJv/ZCe0vo=;\n b=owGbwMvMwCV2MsVw8cxjvkWMp9WSGDL/WUX0TVJ4831ihseucLWv+oczl36RrNpd9XpdZ+7Un\n xONz9Ze7yhlYRDjYpAVU2Tx/eGyv7jbfcpxxTs2MHNYmUCGMHBxCsBE8mYx/E/fpV5Qvux52PPn\n fzPar37+6SAnxjd3Ykak2fv9J51uCMxi+Gd85lqFZH74Hc3tcQeKTA/I+LfNspq86JFwU1/AWcm\n oVi4A", "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-As pointed out by Sashiko:\n https://sashiko.dev/#/patchset/20260501125410.1204490-5-cassel%40kernel.org?part=2\n My patch in v1 unintentionally changed the fairness of\n sata_pmp_qc_defer_cmd_switch().\n-Add a code comment which explains how the ap->excl_link handling works.\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 | 29 ++++++++++--\n drivers/ata/libata-scsi.c | 95 ++++++++++++++++++++++++---------------\n include/linux/libata.h | 8 ++--\n 5 files changed, 104 insertions(+), 52 deletions(-)" }