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Petersen" , Sasha Levin Subject: [PATCH AUTOSEL for 3.18 30/53] scsi: mac_esp: Replace bogus memory barrier with spinlock Thread-Topic: [PATCH AUTOSEL for 3.18 30/53] scsi: mac_esp: Replace bogus memory barrier with spinlock Thread-Index: AQHTtprGZ4tNdetmckeEIrMQBY5q7g== Date: Thu, 8 Mar 2018 05:03:20 +0000 Message-ID: <20180308050230.8876-30-alexander.levin@microsoft.com> References: <20180308050230.8876-1-alexander.levin@microsoft.com> In-Reply-To: <20180308050230.8876-1-alexander.levin@microsoft.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [52.168.54.252] x-ms-publictraffictype: Email x-microsoft-exchange-diagnostics: 1;DM5PR2101MB1030;7:8lXFM5mPLAG4oEvfwp4nHeg2PjE1F3nxux1v8Yp60N0kCWmo40hPTNtgYDU9SD/q2nnGip8dKskrvvBOm2PGNEX+mGZqZ07ZgkHLD1MFgGcHR0Tt3u6cy1darLjMKhTr5PZpDEwLlR2gLcoZQRIeH7Tl78JqPJnzjUqxabnxRdyJ517bgkwDWCbokwNNXgMiXDlPRUC1L3Dse5EgjZ6apb59eLprcw++0p40V7S0zUudNFYr0TlWjlvkC+ob6US4;20:ZWH1H6MIS+TlZCOcztWQ6UpGQXb7mGdes1sUDIvn/N4uoKGjRT1+UcOh2lw5eomJldOAN/cZNE1M/K1XWVzIxhiOuenIplZjgaEEFC9Wp9FtbvQaEKN2H7ZxqHC/5qHUw8j1t9ZLWxXvftdPuIlId7bM34cppBMdrZptZkDUkes= x-ms-office365-filtering-ht: Tenant x-ms-office365-filtering-correlation-id: 6de6d3bd-885d-46f3-da2d-08d584b2b6c1 x-microsoft-antispam: UriScan:;BCL:0;PCL:0;RULEID:(7020095)(4652020)(48565401081)(5600026)(4604075)(3008032)(4534165)(4627221)(201703031133081)(201702281549075)(2017052603328)(7193020);SRVR:DM5PR2101MB1030; x-ms-traffictypediagnostic: DM5PR2101MB1030: authentication-results: spf=none (sender IP is ) smtp.mailfrom=Alexander.Levin@microsoft.com; x-microsoft-antispam-prvs: x-exchange-antispam-report-test: UriScan:(28532068793085)(89211679590171)(85827821059158)(788757137089)(46150409022019)(146099531331640); x-exchange-antispam-report-cfa-test: BCL:0;PCL:0;RULEID:(8211001083)(61425038)(6040501)(2401047)(5005006)(8121501046)(3002001)(10201501046)(3231220)(944501244)(52105095)(93006095)(93001095)(6055026)(61426038)(61427038)(6041288)(20161123562045)(201703131423095)(201702281528075)(20161123555045)(201703061421075)(201703061406153)(20161123560045)(20161123558120)(20161123564045)(6072148)(201708071742011);SRVR:DM5PR2101MB1030;BCL:0;PCL:0;RULEID:;SRVR:DM5PR2101MB1030; x-forefront-prvs: 060503E79B x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(39380400002)(366004)(396003)(39860400002)(346002)(376002)(199004)(189003)(5250100002)(316002)(6666003)(6506007)(2950100002)(26005)(76176011)(68736007)(53936002)(6512007)(59450400001)(2900100001)(86612001)(3660700001)(106356001)(10090500001)(99286004)(2501003)(4326008)(14454004)(102836004)(25786009)(97736004)(6486002)(86362001)(36756003)(7736002)(6116002)(2906002)(478600001)(6436002)(107886003)(72206003)(186003)(3846002)(66066001)(81156014)(10290500003)(1076002)(22452003)(305945005)(110136005)(81166006)(105586002)(3280700002)(54906003)(8936002)(5660300001)(8676002)(22906009)(217873001);DIR:OUT;SFP:1102;SCL:1;SRVR:DM5PR2101MB1030;H:DM5PR2101MB1032.namprd21.prod.outlook.com;FPR:;SPF:None;PTR:InfoNoRecords;A:1;MX:1;LANG:en; x-microsoft-antispam-message-info: Ru62k+u6YhNLQMQ9kBw7m/ULPIDZ32nHvifsFAR/6K1iB99KcHWsrjdnDOCY52OdnROGx51mioTWlSP/9Qe3uh5yKjWcC14hjbPWAPOhbJM0dHVZgMU5ttOaYc24Wxv2lt+dKn4lmmKk7Y5kvJf2mObMlnI9+q1BTKl8jxdCngZzEDHO+YLB9nXgs8uZGUJRtC20HjjYupBNTn3+EgD5BzeR4591NicS5zwQBjH/jhg4OsqqFKGKiUCzuP+qUH+JL1HkWLuwbtNGN+rHgjmJq53MDIgJS2ffim4mIlw01KGK7ckMbVlF/djbakROApDSHdrUHpbY5qR9vWSRj4rFjg== spamdiagnosticoutput: 1:99 spamdiagnosticmetadata: NSPM Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-OriginatorOrg: microsoft.com X-MS-Exchange-CrossTenant-Network-Message-Id: 6de6d3bd-885d-46f3-da2d-08d584b2b6c1 X-MS-Exchange-CrossTenant-originalarrivaltime: 08 Mar 2018 05:03:20.1264 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 72f988bf-86f1-41af-91ab-2d7cd011db47 X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM5PR2101MB1030 Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: From: Finn Thain [ Upstream commit 4da2b1eb230ba4ad19b58984dc52e05b1073df5f ] Commit da244654c66e ("[SCSI] mac_esp: fix for quadras with two esp chips") added mac_scsi_esp_intr() to handle the IRQ lines from a pair of on-board ESP chips (a normal shared IRQ did not work). Proper mutual exclusion was missing from that patch. This patch fixes race conditions between comparison and assignment of esp_chips[] pointers. Signed-off-by: Finn Thain Reviewed-by: Michael Schmitz Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin --- drivers/scsi/mac_esp.c | 33 +++++++++++++++++++++++---------- 1 file changed, 23 insertions(+), 10 deletions(-) diff --git a/drivers/scsi/mac_esp.c b/drivers/scsi/mac_esp.c index 994fc5caf036..79fb6a4f661f 100644 --- a/drivers/scsi/mac_esp.c +++ b/drivers/scsi/mac_esp.c @@ -55,6 +55,7 @@ struct mac_esp_priv { int error; }; static struct esp *esp_chips[2]; +static DEFINE_SPINLOCK(esp_chips_lock); =20 #define MAC_ESP_GET_PRIV(esp) ((struct mac_esp_priv *) \ platform_get_drvdata((struct platform_device *) \ @@ -562,15 +563,18 @@ static int esp_mac_probe(struct platform_device *dev) } =20 host->irq =3D IRQ_MAC_SCSI; - esp_chips[dev->id] =3D esp; - mb(); - if (esp_chips[!dev->id] =3D=3D NULL) { - err =3D request_irq(host->irq, mac_scsi_esp_intr, 0, "ESP", NULL); - if (err < 0) { - esp_chips[dev->id] =3D NULL; - goto fail_free_priv; - } + + /* The request_irq() call is intended to succeed for the first device + * and fail for the second device. + */ + err =3D request_irq(host->irq, mac_scsi_esp_intr, 0, "ESP", NULL); + spin_lock(&esp_chips_lock); + if (err < 0 && esp_chips[!dev->id] =3D=3D NULL) { + spin_unlock(&esp_chips_lock); + goto fail_free_priv; } + esp_chips[dev->id] =3D esp; + spin_unlock(&esp_chips_lock); =20 err =3D scsi_esp_register(esp, &dev->dev); if (err) @@ -579,8 +583,13 @@ static int esp_mac_probe(struct platform_device *dev) return 0; =20 fail_free_irq: - if (esp_chips[!dev->id] =3D=3D NULL) + spin_lock(&esp_chips_lock); + esp_chips[dev->id] =3D NULL; + if (esp_chips[!dev->id] =3D=3D NULL) { + spin_unlock(&esp_chips_lock); free_irq(host->irq, esp); + } else + spin_unlock(&esp_chips_lock); fail_free_priv: kfree(mep); fail_free_command_block: @@ -599,9 +608,13 @@ static int esp_mac_remove(struct platform_device *dev) =20 scsi_esp_unregister(esp); =20 + spin_lock(&esp_chips_lock); esp_chips[dev->id] =3D NULL; - if (!(esp_chips[0] || esp_chips[1])) + if (esp_chips[!dev->id] =3D=3D NULL) { + spin_unlock(&esp_chips_lock); free_irq(irq, NULL); + } else + spin_unlock(&esp_chips_lock); =20 kfree(mep); =20 --=20 2.14.1