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{ "id": 2231873, "url": "http://patchwork.ozlabs.org/api/1.2/covers/2231873/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linux-ide/cover/20260501125410.1204490-5-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": "<20260501125410.1204490-5-cassel@kernel.org>", "list_archive_url": null, "date": "2026-05-01T12:54:10", "name": "[0/3] 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/20260501125410.1204490-5-cassel@kernel.org/mbox/", "series": [ { "id": 502457, "url": "http://patchwork.ozlabs.org/api/1.2/series/502457/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linux-ide/list/?series=502457", "date": "2026-05-01T12:54:13", "name": "ata: fix deferred QC handling for port multipliers", "version": 1, "mbox": "http://patchwork.ozlabs.org/series/502457/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/covers/2231873/comments/", "headers": { "Return-Path": "\n <linux-ide+bounces-5616-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=aiy3OFNy;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org\n (client-ip=2600:3c0a:e001:db::12fc:5321; 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Fri, 1 May 2026 12:54:17 +0000 (UTC)", "by smtp.kernel.org (Postfix) with ESMTPSA id B27C8C2BCB4;\n\tFri, 1 May 2026 12:54:15 +0000 (UTC)" ], "ARC-Seal": "i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116;\n\tt=1777640058; cv=none;\n b=TvEroaUhSjUfA82volUm0VAaR3s16dac6teWeiyq2Kfyq/nR4+iazpA2kbZ9a2h+q0q/04hNEVd3buJiS/iIQqx1sXHDzFnkjmMx3Oyd9oB8ObHheBQIqHvKRl4TEyrZut4/RUvxVKzgoX6mRq3oWOEsflq5guB5glDbWinfY74=", "ARC-Message-Signature": "i=1; a=rsa-sha256; d=subspace.kernel.org;\n\ts=arc-20240116; t=1777640058; c=relaxed/simple;\n\tbh=tRhne4xZO4vowxLhLEkRdR05M8fXX8vWoXpX2TXIvhA=;\n\th=From:To:Cc:Subject:Date:Message-ID:MIME-Version;\n b=Uj5QpsgOvIIi6LkzDx5KkYzUItmBVuFCreu6ejkrcVeKx9VzELyq6Qy1L/oTtmdQK3bpbRvYsSlDmNb10n33PY5ZPGNjhbYU3cV9qvPrQhPGYqUeXY4dZVCvlyo8ndvdW1GTYCGLHhL7kPpcHF+gM/DbNFhz7uRB2mXlpwDVxSE=", "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=aiy3OFNy; 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=1777640057;\n\tbh=tRhne4xZO4vowxLhLEkRdR05M8fXX8vWoXpX2TXIvhA=;\n\th=From:To:Cc:Subject:Date:From;\n\tb=aiy3OFNyE91j7eSe1LZXV6sGf6LwpI1L4uqj4qn7weEknaGHNu8Quh0ywdbUOk/3s\n\t 4fV2YdFzO8ZFic9fug9S83G76yc9Rzko2Slclin69NQ5FoDecpXoe9Sz2orsi194M8\n\t 6vtFDW2XRrffLZSOD9J5n/zmZev0vd7n4k/BQZHZS6vOtVqrJZ+Td1rHJBlCk9BWNw\n\t ctwApai3jLFukIaSXBeyj98Dh72o4VjSXLYEo9VGm1aTUdmyl3cZXPwDMH5gi8TI12\n\t ENzzA0xelQ4Uy/k7N4utmjJkPqlXHHp1EmyMGhOpiBWClsRY4BAk5YvHDCdlhmBA5A\n\t xb5lgUcaZLfyg==", "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\tTejun Heo <htejun@gmail.com>,\n\tJeff Garzik <jeff@garzik.org>,\n\tJohn Garry <john.g.garry@oracle.com>,\n\t\"Martin K. Petersen\" <martin.petersen@oracle.com>", "Cc": "linux-ide@vger.kernel.org", "Subject": "[PATCH 0/3] ata: fix deferred QC handling for port multipliers", "Date": "Fri, 1 May 2026 14:54:10 +0200", "Message-ID": "<20260501125410.1204490-5-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=1932; i=cassel@kernel.org;\n h=from:subject; bh=tRhne4xZO4vowxLhLEkRdR05M8fXX8vWoXpX2TXIvhA=;\n b=owGbwMvMwCV2MsVw8cxjvkWMp9WSGDK/LCpKjiro7W/XVT6y9O7SR+tV43YcvpQ/9+q2XNvIX\n cmBN663d5SyMIhxMciKKbL4/nDZX9ztPuW44h0bmDmsTCBDGLg4BWAiqnUM/z1MRIxaN1tO+f3Y\n 5IuWxtlNWTZ3O6cyTin9J6laeNNcYSXD/9Irekw1ce8N5vBMmvDyG1N153YhntTlljV2L/5wfbB\n 6xgsA", "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\nTo me, this appears to be a problem in ata_pmp_qc_defer_cmd_switch() that\nhas been there since this function was introduced. ap->excl_link did not\nalways get set. This is fixed in patch 1/3.\n\nWhile looking at the code, when using a PMP with CBS, it turns out that we\nare incorrectly using the deferred_qc feature that issues a QC via a\nworkqueue, even for non-NCQ commands that are issued to another link\n(a link that is not the active link). This workqueue feature was meant to\navoid dealing with non-NCQ vs NCQ commands for a single drive, not to\nduplicate the existing ap->excl_link logic. This is fixed in patch 2/3.\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 3/3.\n\nTommy, it would be nice if you could apply this series and see if it solves\nyour problem. Right now the series is compile tested only.\n\n\nNiklas Cassel (3):\n ata: libata-pmp: fix ata_pmp_qc_defer_cmd_switch()\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 | 13 +++++---\n drivers/ata/libata-scsi.c | 66 ++++++++++++++++++++++-----------------\n include/linux/libata.h | 6 ++--\n 5 files changed, 64 insertions(+), 45 deletions(-)" }