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[35.245.152.114]) by smtp.gmail.com with ESMTPSA id pa20-20020a05620a831400b0078f13e59dc9sm4224921qkn.102.2024.05.06.14.10.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 06 May 2024 14:10:32 -0700 (PDT) From: Ricardo Ribalda Date: Mon, 06 May 2024 21:10:30 +0000 Subject: [PATCH 5/5] media: drivers/media/dvb-core: Refactor dvb_frontend_open Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20240506-cocci-locks-v1-5-a67952fe5d19@chromium.org> References: <20240506-cocci-locks-v1-0-a67952fe5d19@chromium.org> In-Reply-To: <20240506-cocci-locks-v1-0-a67952fe5d19@chromium.org> To: Andy Walls , Mauro Carvalho Chehab , Sean Young , Jarod Wilson Cc: Hans Verkuil , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Ricardo Ribalda X-Mailer: b4 0.12.4 Move the shared frontend logic to its own function. This allows using guard() to handle the mfe_lock mutex, and using lockdep asserts. There is no intended change of behavior in this code. This fixes the following cocci warnings: drivers/media/dvb-core/dvb_frontend.c:2897:1-7: preceding lock on line 2776 drivers/media/dvb-core/dvb_frontend.c:2897:1-7: preceding lock on line 2786 drivers/media/dvb-core/dvb_frontend.c:2897:1-7: preceding lock on line 2809 Signed-off-by: Ricardo Ribalda --- drivers/media/dvb-core/dvb_frontend.c | 116 ++++++++++++++++++++-------------- 1 file changed, 69 insertions(+), 47 deletions(-) diff --git a/drivers/media/dvb-core/dvb_frontend.c b/drivers/media/dvb-core/dvb_frontend.c index 4f78f30b3646..d04a6092f1ba 100644 --- a/drivers/media/dvb-core/dvb_frontend.c +++ b/drivers/media/dvb-core/dvb_frontend.c @@ -30,6 +30,7 @@ #include #include #include +#include #include #include @@ -2760,66 +2761,70 @@ static __poll_t dvb_frontend_poll(struct file *file, struct poll_table_struct *w return 0; } -static int dvb_frontend_open(struct inode *inode, struct file *file) +static int dvb_get_shared_frontend(struct dvb_adapter *adapter, + struct dvb_device *dvbdev, + struct file *file) { - struct dvb_device *dvbdev = file->private_data; - struct dvb_frontend *fe = dvbdev->priv; - struct dvb_frontend_private *fepriv = fe->frontend_priv; - struct dvb_adapter *adapter = fe->dvb; - int ret; + struct dvb_device *mfedev; + struct dvb_frontend *mfe; + struct dvb_frontend_private *mfepriv; + int mferetry; - dev_dbg(fe->dvb->device, "%s:\n", __func__); - if (fe->exit == DVB_FE_DEVICE_REMOVED) - return -ENODEV; + lockdep_assert_held(&adapter->mfe_lock); if (adapter->mfe_shared == 2) { - mutex_lock(&adapter->mfe_lock); if ((file->f_flags & O_ACCMODE) != O_RDONLY) { if (adapter->mfe_dvbdev && !adapter->mfe_dvbdev->writers) { - mutex_unlock(&adapter->mfe_lock); return -EBUSY; } adapter->mfe_dvbdev = dvbdev; } - } else if (adapter->mfe_shared) { - mutex_lock(&adapter->mfe_lock); + return 0; + } - if (!adapter->mfe_dvbdev) - adapter->mfe_dvbdev = dvbdev; + if (!adapter->mfe_dvbdev) { + adapter->mfe_dvbdev = dvbdev; + return 0; + } - else if (adapter->mfe_dvbdev != dvbdev) { - struct dvb_device - *mfedev = adapter->mfe_dvbdev; - struct dvb_frontend - *mfe = mfedev->priv; - struct dvb_frontend_private - *mfepriv = mfe->frontend_priv; - int mferetry = (dvb_mfe_wait_time << 1); - - mutex_unlock(&adapter->mfe_lock); - while (mferetry-- && (mfedev->users != -1 || - mfepriv->thread)) { - if (msleep_interruptible(500)) { - if (signal_pending(current)) - return -EINTR; - } - } + if (adapter->mfe_dvbdev == dvbdev) + return 0; - mutex_lock(&adapter->mfe_lock); - if (adapter->mfe_dvbdev != dvbdev) { - mfedev = adapter->mfe_dvbdev; - mfe = mfedev->priv; - mfepriv = mfe->frontend_priv; - if (mfedev->users != -1 || - mfepriv->thread) { - mutex_unlock(&adapter->mfe_lock); - return -EBUSY; - } - adapter->mfe_dvbdev = dvbdev; + mfedev = adapter->mfe_dvbdev; + mfe = mfedev->priv; + mfepriv = mfe->frontend_priv; + mferetry = (dvb_mfe_wait_time << 1); + + mutex_unlock(&adapter->mfe_lock); + while (mferetry-- && (mfedev->users != -1 || mfepriv->thread)) { + if (msleep_interruptible(500)) { + if (signal_pending(current)) { + mutex_lock(&adapter->mfe_lock); + return -EINTR; } } } + mutex_lock(&adapter->mfe_lock); + + if (adapter->mfe_dvbdev != dvbdev) { + mfedev = adapter->mfe_dvbdev; + mfe = mfedev->priv; + mfepriv = mfe->frontend_priv; + if (mfedev->users != -1 || mfepriv->thread) + return -EBUSY; + adapter->mfe_dvbdev = dvbdev; + } + + return 0; +} + +static int __dvb_frontend_open(struct inode *inode, struct file *file) +{ + struct dvb_device *dvbdev = file->private_data; + struct dvb_frontend *fe = dvbdev->priv; + struct dvb_frontend_private *fepriv = fe->frontend_priv; + int ret; if (dvbdev->users == -1 && fe->ops.ts_bus_ctrl) { if ((ret = fe->ops.ts_bus_ctrl(fe, 1)) < 0) @@ -2871,8 +2876,6 @@ static int dvb_frontend_open(struct inode *inode, struct file *file) dvb_frontend_get(fe); - if (adapter->mfe_shared) - mutex_unlock(&adapter->mfe_lock); return ret; err3: @@ -2892,11 +2895,30 @@ static int dvb_frontend_open(struct inode *inode, struct file *file) if (dvbdev->users == -1 && fe->ops.ts_bus_ctrl) fe->ops.ts_bus_ctrl(fe, 0); err0: - if (adapter->mfe_shared) - mutex_unlock(&adapter->mfe_lock); return ret; } +static int dvb_frontend_open(struct inode *inode, struct file *file) +{ + struct dvb_device *dvbdev = file->private_data; + struct dvb_frontend *fe = dvbdev->priv; + struct dvb_adapter *adapter = fe->dvb; + int ret; + + dev_dbg(fe->dvb->device, "%s:\n", __func__); + if (fe->exit == DVB_FE_DEVICE_REMOVED) + return -ENODEV; + + if (!adapter->mfe_shared) + return __dvb_frontend_open(inode, file); + + guard(mutex)(&adapter->mfe_lock); + ret = dvb_get_shared_frontend(adapter, dvbdev, file); + if (ret) + return ret; + return __dvb_frontend_open(inode, file); +} + static int dvb_frontend_release(struct inode *inode, struct file *file) { struct dvb_device *dvbdev = file->private_data;