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Tue, 20 Aug 2024 20:50:08 GMT Received: from hu-bjorande-lv.qualcomm.com (10.49.16.6) by nalasex01c.na.qualcomm.com (10.47.97.35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1544.9; Tue, 20 Aug 2024 13:50:07 -0700 From: Bjorn Andersson Date: Tue, 20 Aug 2024 13:29:31 -0700 Subject: [PATCH v3 2/3] usb: typec: ucsi: Move unregister out of atomic section Precedence: bulk X-Mailing-List: linux-arm-msm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-ID: <20240820-pmic-glink-v6-11-races-v3-2-eec53c750a04@quicinc.com> References: <20240820-pmic-glink-v6-11-races-v3-0-eec53c750a04@quicinc.com> In-Reply-To: <20240820-pmic-glink-v6-11-races-v3-0-eec53c750a04@quicinc.com> To: X-Mailer: b4 0.14.1 X-Developer-Signature: v=1; a=ed25519-sha256; t=1724187007; l=4533; i=quic_bjorande@quicinc.com; s=20230915; h=from:subject:message-id; bh=8ZnntggynUfcTpvzbLLS3cPahVXCc4McD2LWNojoosg=; b=/3DYVyq94KEEq0R8IhUmUgEIKB4rMOESsVyMu/oITe6q9Q95xTFEAGNZomcimWEYQ3KPUn9lY N651kkQInJHC8gfr9c8N9kdPnb7/2cFFx/v3sCP+LdAuJd3EbQ+DoOS X-Developer-Key: i=quic_bjorande@quicinc.com; a=ed25519; pk=VkhObtljigy9k0ZUIE1Mvr0Y+E1dgBEH9WoLQnUtbIM= X-ClientProxiedBy: nalasex01b.na.qualcomm.com (10.47.209.197) To nalasex01c.na.qualcomm.com (10.47.97.35) X-QCInternal: smtphost X-Proofpoint-Virus-Version: vendor=nai engine=6200 definitions=5800 signatures=585085 X-Proofpoint-GUID: 0TAdmtLpt9X7R91kxnYCcPGRpwhnoi5O X-Proofpoint-ORIG-GUID: 0TAdmtLpt9X7R91kxnYCcPGRpwhnoi5O X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1039,Hydra:6.0.680,FMLib:17.12.28.16 definitions=2024-08-20_16,2024-08-19_03,2024-05-17_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 phishscore=0 impostorscore=0 lowpriorityscore=0 bulkscore=0 mlxscore=0 malwarescore=0 priorityscore=1501 adultscore=0 suspectscore=0 mlxlogscore=999 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2407110000 definitions=main-2408200152 Commit '9329933699b3 ("soc: qcom: pmic_glink: Make client-lock non-sleeping")' moved the pmic_glink client list under a spinlock, as it is accessed by the rpmsg/glink callback, which in turn is invoked from IRQ context. This means that ucsi_unregister() is now called from atomic context, which isn't feasible as it's expecting a sleepable context. An effort is under way to get GLINK to invoke its callbacks in a sleepable context, but until then lets schedule the unregistration. A side effect of this is that ucsi_unregister() can now happen after the remote processor, and thereby the communication link with it, is gone. pmic_glink_send() is amended with a check to avoid the resulting NULL pointer dereference. This does however result in the user being informed about this error by the following entry in the kernel log: ucsi_glink.pmic_glink_ucsi pmic_glink.ucsi.0: failed to send UCSI write request: -5 Fixes: 9329933699b3 ("soc: qcom: pmic_glink: Make client-lock non-sleeping") Cc: stable@vger.kernel.org Reviewed-by: Heikki Krogerus Reviewed-by: Neil Armstrong Reviewed-by: Dmitry Baryshkov Tested-by: Amit Pundir Reviewed-by: Johan Hovold Tested-by: Johan Hovold Signed-off-by: Bjorn Andersson --- drivers/soc/qcom/pmic_glink.c | 10 +++++++++- drivers/usb/typec/ucsi/ucsi_glink.c | 27 ++++++++++++++++++++++----- 2 files changed, 31 insertions(+), 6 deletions(-) diff --git a/drivers/soc/qcom/pmic_glink.c b/drivers/soc/qcom/pmic_glink.c index 53b176d04fbd..b218460219b7 100644 --- a/drivers/soc/qcom/pmic_glink.c +++ b/drivers/soc/qcom/pmic_glink.c @@ -112,8 +112,16 @@ EXPORT_SYMBOL_GPL(pmic_glink_client_register); int pmic_glink_send(struct pmic_glink_client *client, void *data, size_t len) { struct pmic_glink *pg = client->pg; + int ret; - return rpmsg_send(pg->ept, data, len); + mutex_lock(&pg->state_lock); + if (!pg->ept) + ret = -ECONNRESET; + else + ret = rpmsg_send(pg->ept, data, len); + mutex_unlock(&pg->state_lock); + + return ret; } EXPORT_SYMBOL_GPL(pmic_glink_send); diff --git a/drivers/usb/typec/ucsi/ucsi_glink.c b/drivers/usb/typec/ucsi/ucsi_glink.c index 6425904f2bfc..ca89f9037f08 100644 --- a/drivers/usb/typec/ucsi/ucsi_glink.c +++ b/drivers/usb/typec/ucsi/ucsi_glink.c @@ -68,6 +68,9 @@ struct pmic_glink_ucsi { struct work_struct notify_work; struct work_struct register_work; + spinlock_t state_lock; + bool ucsi_registered; + bool pd_running; u8 read_buf[UCSI_BUF_SIZE]; }; @@ -244,8 +247,20 @@ static void pmic_glink_ucsi_notify(struct work_struct *work) static void pmic_glink_ucsi_register(struct work_struct *work) { struct pmic_glink_ucsi *ucsi = container_of(work, struct pmic_glink_ucsi, register_work); + unsigned long flags; + bool pd_running; - ucsi_register(ucsi->ucsi); + spin_lock_irqsave(&ucsi->state_lock, flags); + pd_running = ucsi->pd_running; + spin_unlock_irqrestore(&ucsi->state_lock, flags); + + if (!ucsi->ucsi_registered && pd_running) { + ucsi_register(ucsi->ucsi); + ucsi->ucsi_registered = true; + } else if (ucsi->ucsi_registered && !pd_running) { + ucsi_unregister(ucsi->ucsi); + ucsi->ucsi_registered = false; + } } static void pmic_glink_ucsi_callback(const void *data, size_t len, void *priv) @@ -269,11 +284,12 @@ static void pmic_glink_ucsi_callback(const void *data, size_t len, void *priv) static void pmic_glink_ucsi_pdr_notify(void *priv, int state) { struct pmic_glink_ucsi *ucsi = priv; + unsigned long flags; - if (state == SERVREG_SERVICE_STATE_UP) - schedule_work(&ucsi->register_work); - else if (state == SERVREG_SERVICE_STATE_DOWN) - ucsi_unregister(ucsi->ucsi); + spin_lock_irqsave(&ucsi->state_lock, flags); + ucsi->pd_running = (state == SERVREG_SERVICE_STATE_UP); + spin_unlock_irqrestore(&ucsi->state_lock, flags); + schedule_work(&ucsi->register_work); } static void pmic_glink_ucsi_destroy(void *data) @@ -320,6 +336,7 @@ static int pmic_glink_ucsi_probe(struct auxiliary_device *adev, INIT_WORK(&ucsi->register_work, pmic_glink_ucsi_register); init_completion(&ucsi->read_ack); init_completion(&ucsi->write_ack); + spin_lock_init(&ucsi->state_lock); mutex_init(&ucsi->lock); ucsi->ucsi = ucsi_create(dev, &pmic_glink_ucsi_ops);