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[34.145.178.123]) by smtp.gmail.com with ESMTPSA id 6a1803df08f44-6b08bf006f4sm6392076d6.90.2024.06.11.04.03.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 11 Jun 2024 04:03:05 -0700 (PDT) From: Ricardo Ribalda Date: Tue, 11 Jun 2024 11:02:58 +0000 Subject: [PATCH 2/2] media: drivers/media/dvb-core: Refactor dvb_frontend_open locking Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20240611-coccinelle-followup-v1-2-df2de9c2f320@chromium.org> References: <20240611-coccinelle-followup-v1-0-df2de9c2f320@chromium.org> In-Reply-To: <20240611-coccinelle-followup-v1-0-df2de9c2f320@chromium.org> To: Mauro Carvalho Chehab Cc: linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, Hans Verkuil , Ricardo Ribalda X-Mailer: b4 0.13.0 Split out the wait function, and introduce some new toys: guard and lockdep. 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 | 59 ++++++++++++++++++++++------------- 1 file changed, 38 insertions(+), 21 deletions(-) diff --git a/drivers/media/dvb-core/dvb_frontend.c b/drivers/media/dvb-core/dvb_frontend.c index e81b9996530e..a7739f5e78cb 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 @@ -2826,6 +2827,34 @@ static int __dvb_frontend_open(struct inode *inode, struct file *file) return ret; } +static int wait_dvb_frontend(struct dvb_adapter *adapter, + struct dvb_device *mfedev) +{ + struct dvb_frontend *mfe = mfedev->priv; + struct dvb_frontend_private *mfepriv = mfe->frontend_priv; + int mferetry = (dvb_mfe_wait_time << 1); + int ret = 0; + + lockdep_assert_held(&adapter->mfe_lock); + + if (mfedev->users == -1 && !mfepriv->thread) + return 0; + + mutex_unlock(&adapter->mfe_lock); + + while (mferetry-- && (mfedev->users != -1 || mfepriv->thread)) { + if (msleep_interruptible(500)) + if (signal_pending(current)) { + ret = -EINTR; + break; + } + } + + mutex_lock(&adapter->mfe_lock); + + return ret; +} + static int dvb_frontend_open(struct inode *inode, struct file *file) { struct dvb_device *dvbdev = file->private_data; @@ -2840,19 +2869,17 @@ static int dvb_frontend_open(struct inode *inode, struct file *file) if (!adapter->mfe_shared) return __dvb_frontend_open(inode, file); + + guard(mutex)(&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); + !adapter->mfe_dvbdev->writers) return -EBUSY; - } adapter->mfe_dvbdev = dvbdev; } } else { - mutex_lock(&adapter->mfe_lock); - if (!adapter->mfe_dvbdev) { adapter->mfe_dvbdev = dvbdev; } else if (adapter->mfe_dvbdev != dvbdev) { @@ -2862,34 +2889,24 @@ static int dvb_frontend_open(struct inode *inode, struct file *file) *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; - } - } - mutex_lock(&adapter->mfe_lock); + ret = wait_dvb_frontend(adapter, mfedev); + if (ret) + return ret; + 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); + mfepriv->thread) return -EBUSY; - } adapter->mfe_dvbdev = dvbdev; } } } ret = __dvb_frontend_open(inode, file); - mutex_unlock(&adapter->mfe_lock); return ret; }