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GET /api/1.2/patches/2231874/?format=api
{ "id": 2231874, "url": "http://patchwork.ozlabs.org/api/1.2/patches/2231874/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linux-ide/patch/20260501125410.1204490-6-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": "<20260501125410.1204490-6-cassel@kernel.org>", "list_archive_url": null, "date": "2026-05-01T12:54:11", "name": "[1/3] ata: libata-pmp: fix ata_pmp_qc_defer_cmd_switch()", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "71bd256cd69076e0fcd5abfee9920ca82f0cfaa4", "submitter": { "id": 87751, "url": "http://patchwork.ozlabs.org/api/1.2/people/87751/?format=api", "name": "Niklas Cassel", "email": "cassel@kernel.org" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/linux-ide/patch/20260501125410.1204490-6-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/patches/2231874/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/2231874/checks/", "tags": {}, "related": [], "headers": { "Return-Path": "\n <linux-ide+bounces-5617-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=dTZ77YbJ;\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; 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Fri, 1 May 2026 12:54:20 +0000 (UTC)", "by smtp.kernel.org (Postfix) with ESMTPSA id 6DF91C2BCB4;\n\tFri, 1 May 2026 12:54:18 +0000 (UTC)" ], "ARC-Seal": "i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116;\n\tt=1777640060; cv=none;\n b=m/14+qF7wMUqC58N8LkHOi6g8HTeo1N9A0BoyjUWU76GLQSd58Ef9v28+vO6XbpDWIZfkyeDz7m37i75nw4vlRVjkRAlYBje1Q8bmTOEm7XhvPmHmnPRn7WV4xs1HaNG+A0GoZ1aiJJFQj0DXoXqZ2ZEFvPfLPvYn/qJlhxsz+4=", "ARC-Message-Signature": "i=1; a=rsa-sha256; d=subspace.kernel.org;\n\ts=arc-20240116; t=1777640060; c=relaxed/simple;\n\tbh=L8uQm7kM3a+kcQdyEEYhxRl8Ejj5hBxFkHbbLREeoek=;\n\th=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References:\n\t MIME-Version;\n b=dO6LYoK//b/qQ3TxNBoCVAqY0pu5NzurZxafbX1+X4oLmgrkADminucSuEYIqIdsiDOmwy9RvtbB4FtsrOZy4R3wU/MluSlbJaE6JzxOp56QxcuvOPu9t0qZeQfxUR8cXDhY8u8YtNCMXcPx3ssGOUmt1cVeeUoyAvZdr/uIYe8=", "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=dTZ77YbJ; 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=1777640059;\n\tbh=L8uQm7kM3a+kcQdyEEYhxRl8Ejj5hBxFkHbbLREeoek=;\n\th=From:To:Cc:Subject:Date:In-Reply-To:References:From;\n\tb=dTZ77YbJLkuGmr/M6iuhXIcIGm04N7nOgyL188IRADLz3NpQz9R5+Gq1O9i58Il0u\n\t pD/X9AcATBJaqFEJfgLEaNUWgxrJbgEZmufMhcXuu+yqcy1s+i2+Lpzz0ikWgHYgwj\n\t 4VRbQzM5z3/2xR1308b4w0d+fmQPmwEWt7i8woSWVkATiL2vtmweh2x4gWGLuxBZne\n\t cXx1JxIS86AIOENT58ZLL0o2E+XjWYxZ7tp3KENjQnPVKVfzGdGzsTT9WN6m5v3AOp\n\t /QVVqzcMdl7oIdC4bEkea6mYALhFbXOsCzw8xPVvjeBpkgAk0YSbVBZZwvT5ZIIdod\n\t pqgycEnfsbpPw==", "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>", "Cc": "linux-ide@vger.kernel.org", "Subject": "[PATCH 1/3] ata: libata-pmp: fix ata_pmp_qc_defer_cmd_switch()", "Date": "Fri, 1 May 2026 14:54:11 +0200", "Message-ID": "<20260501125410.1204490-6-cassel@kernel.org>", "X-Mailer": "git-send-email 2.54.0", "In-Reply-To": "<20260501125410.1204490-5-cassel@kernel.org>", "References": "<20260501125410.1204490-5-cassel@kernel.org>", "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=2598; i=cassel@kernel.org;\n h=from:subject; bh=L8uQm7kM3a+kcQdyEEYhxRl8Ejj5hBxFkHbbLREeoek=;\n b=owGbwMvMwCV2MsVw8cxjvkWMp9WSGDK/LCpSuytYuGeVhe9M8VLlMyKih/8nyszM7P8czLlS4\n GjzPvsVHaUsDGJcDLJiiiy+P1z2F3e7TzmueMcGZg4rE8gQBi5OAZjIJ1+GP5zfP86M72ZstGl4\n fPWq0lrp6QtcWVoyD/zSk79ka8pWkMbIML83M65K9311isuei/sN3bieNm3SU2naIvna7Phcd80\n ERgA=", "X-Developer-Key": "i=cassel@kernel.org; a=openpgp;\n fpr=5ADE635C0E631CBBD5BE065A352FE6582ED9B5DA", "Content-Transfer-Encoding": "8bit" }, "content": "When using Port Multipliers (PMPs) with Command-Based Switching (CBS), you\ncan only issue commands to one link at a time.\n\nThis is implemented in sata_pmp_qc_defer_cmd_switch() by setting\nap->excl_link if there is no link currently being exclusive, and setting\nqc->flags ATA_QCFLAG_CLEAR_EXCL to clear the exlusive link in\n__ata_qc_complete().\n\nATA_QCFLAG_CLEAR_EXCL is only set if this is the first link to become\nactive, or if (since CBS can only have one active link) the current link\nis active. __ata_qc_complete() clears ap->excl_link as long as\nATA_QCFLAG_CLEAR_EXCL is set, it does not matter if there are still\noutstanding requests to the same link. This works because\nsata_pmp_qc_defer_cmd_switch() will only allow new commands to be queued\nif (ap->nr_active_links == 0 || ata_link_active(link)).\n\nHowever, since sata_pmp_qc_defer_cmd_switch() does a:\nreturn ata_std_qc_defer(qc); before setting ap->excl_link, this means that\nin the case where ap->excl_link == NULL and ata_std_qc_defer() returns 0\n(i.e. the QC should not be deferred), we would not set ap->excl_link.\n\nAdditionally, think of the following example:\nNCQ command1 to drive1 issued:\nsets ATA_QCFLAG_CLEAR_EXCL\ndoes not set ap->excl_link\n\nNCQ command2 to drive1 issued:\nsets ATA_QCFLAG_CLEAR_EXCL\ndoes not set ap->excl_link\n\nNCQ command3 to drive2 issued:\nap->excl_link gets set\ndoes not set ATA_QCFLAG_CLEAR_EXCL\nreturns ATA_DEFER_PORT\n\nFor command3, it seems wrong to set ap->excl_link while also deferring the\ncommand with ATA_DEFER_PORT.\n\nModify sata_pmp_qc_defer_cmd_switch() to only set ap->excl_link if we can\nactually issue a command (i.e. if we don't return ATA_DEFER_PORT or\nATA_DEFER_LINK).\n\nFixes: 31f88384443b (\"libata-pmp: implement qc_defer for command switching PMP support\")\nSigned-off-by: Niklas Cassel <cassel@kernel.org>\n---\n drivers/ata/libata-pmp.c | 9 ++++++---\n 1 file changed, 6 insertions(+), 3 deletions(-)", "diff": "diff --git a/drivers/ata/libata-pmp.c b/drivers/ata/libata-pmp.c\nindex e3adc008fed1..0575e1e283d8 100644\n--- a/drivers/ata/libata-pmp.c\n+++ b/drivers/ata/libata-pmp.c\n@@ -113,11 +113,14 @@ int sata_pmp_qc_defer_cmd_switch(struct ata_queued_cmd *qc)\n \n \tif (ap->excl_link == NULL || ap->excl_link == link) {\n \t\tif (ap->nr_active_links == 0 || ata_link_active(link)) {\n+\t\t\tint ret;\n+\n \t\t\tqc->flags |= ATA_QCFLAG_CLEAR_EXCL;\n-\t\t\treturn ata_std_qc_defer(qc);\n+\t\t\tret = ata_std_qc_defer(qc);\n+\t\t\tif (!ret)\n+\t\t\t\tap->excl_link = link;\n+\t\t\treturn ret;\n \t\t}\n-\n-\t\tap->excl_link = link;\n \t}\n \n \treturn ATA_DEFER_PORT;\n", "prefixes": [ "1/3" ] }