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 <ribalda@xxxxxxxxxxxx> --- 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 <linux/kthread.h> #include <linux/ktime.h> #include <linux/compat.h> +#include <linux/lockdep.h> #include <asm/processor.h> #include <media/dvb_frontend.h> @@ -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; } -- 2.45.2.505.gda0bf45e8d-goog