[media] dib0700: Return -EINTR and unlock mutex if locking attempts fails.

  From: Santosh Nayak <santoshprasadnayak@gmail.com>


In 'dib0700_i2c_xfer_new()' and 'dib0700_i2c_xfer_legacy()'
we are taking two locks:
		1. i2c_mutex
		2. usb_mutex
If attempt to take 'usb_mutex' lock fails then the previously taken
lock 'i2c_mutex' should be unlocked and -EINTR should be return so
that caller can take appropriate action.

If locking attempt was interrupted by a signal then
we should return -EINTR. At present we are returning '0' for
such scenarios  which is wrong.

Signed-off-by: Santosh Nayak <santoshprasadnayak@gmail.com>
---
 drivers/media/dvb/dvb-usb/dib0700_core.c |   20 +++++++++++---------
 1 files changed, 11 insertions(+), 9 deletions(-)
  

Can anyone please review it ?


regards
Santosh

On Fri, Mar 16, 2012 at 6:15 PM, santosh nayak
<santoshprasadnayak@gmail.com> wrote:
> From: Santosh Nayak <santoshprasadnayak@gmail.com>
>
>
> In 'dib0700_i2c_xfer_new()' and 'dib0700_i2c_xfer_legacy()'
> we are taking two locks:
>                1. i2c_mutex
>                2. usb_mutex
> If attempt to take 'usb_mutex' lock fails then the previously taken
> lock 'i2c_mutex' should be unlocked and -EINTR should be return so
> that caller can take appropriate action.
>
> If locking attempt was interrupted by a signal then
> we should return -EINTR. At present we are returning '0' for
> such scenarios  which is wrong.
>
> Signed-off-by: Santosh Nayak <santoshprasadnayak@gmail.com>
> ---
>  drivers/media/dvb/dvb-usb/dib0700_core.c |   20 +++++++++++---------
>  1 files changed, 11 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/media/dvb/dvb-usb/dib0700_core.c b/drivers/media/dvb/dvb-usb/dib0700_core.c
> index 070e82a..1a6ddbc 100644
> --- a/drivers/media/dvb/dvb-usb/dib0700_core.c
> +++ b/drivers/media/dvb/dvb-usb/dib0700_core.c
> @@ -32,7 +32,7 @@ int dib0700_get_version(struct dvb_usb_device *d, u32 *hwversion,
>
>        if (mutex_lock_interruptible(&d->usb_mutex) < 0) {
>                err("could not acquire lock");
> -               return 0;
> +               return -EINTR;
>        }
>
>        ret = usb_control_msg(d->udev, usb_rcvctrlpipe(d->udev, 0),
> @@ -118,7 +118,7 @@ int dib0700_set_gpio(struct dvb_usb_device *d, enum dib07x0_gpios gpio, u8 gpio_
>
>        if (mutex_lock_interruptible(&d->usb_mutex) < 0) {
>                err("could not acquire lock");
> -               return 0;
> +               return -EINTR;
>        }
>
>        st->buf[0] = REQUEST_SET_GPIO;
> @@ -139,7 +139,7 @@ static int dib0700_set_usb_xfer_len(struct dvb_usb_device *d, u16 nb_ts_packets)
>        if (st->fw_version >= 0x10201) {
>                if (mutex_lock_interruptible(&d->usb_mutex) < 0) {
>                        err("could not acquire lock");
> -                       return 0;
> +                       return -EINTR;
>                }
>
>                st->buf[0] = REQUEST_SET_USB_XFER_LEN;
> @@ -228,7 +228,8 @@ static int dib0700_i2c_xfer_new(struct i2c_adapter *adap, struct i2c_msg *msg,
>                        /* Write request */
>                        if (mutex_lock_interruptible(&d->usb_mutex) < 0) {
>                                err("could not acquire lock");
> -                               return 0;
> +                               mutex_unlock(&d->i2c_mutex);
> +                               return -EINTR;
>                        }
>                        st->buf[0] = REQUEST_NEW_I2C_WRITE;
>                        st->buf[1] = msg[i].addr << 1;
> @@ -274,7 +275,8 @@ static int dib0700_i2c_xfer_legacy(struct i2c_adapter *adap,
>                return -EAGAIN;
>        if (mutex_lock_interruptible(&d->usb_mutex) < 0) {
>                err("could not acquire lock");
> -               return 0;
> +               mutex_unlock(&d->i2c_mutex);
> +               return -EINTR;
>        }
>
>        for (i = 0; i < num; i++) {
> @@ -369,7 +371,7 @@ static int dib0700_set_clock(struct dvb_usb_device *d, u8 en_pll,
>
>        if (mutex_lock_interruptible(&d->usb_mutex) < 0) {
>                err("could not acquire lock");
> -               return 0;
> +               return -EINTR;
>        }
>
>        st->buf[0] = REQUEST_SET_CLOCK;
> @@ -401,7 +403,7 @@ int dib0700_set_i2c_speed(struct dvb_usb_device *d, u16 scl_kHz)
>
>        if (mutex_lock_interruptible(&d->usb_mutex) < 0) {
>                err("could not acquire lock");
> -               return 0;
> +               return -EINTR;
>        }
>
>        st->buf[0] = REQUEST_SET_I2C_PARAM;
> @@ -561,7 +563,7 @@ int dib0700_streaming_ctrl(struct dvb_usb_adapter *adap, int onoff)
>
>        if (mutex_lock_interruptible(&adap->dev->usb_mutex) < 0) {
>                err("could not acquire lock");
> -               return 0;
> +               return -EINTR;
>        }
>
>        st->buf[0] = REQUEST_ENABLE_VIDEO;
> @@ -611,7 +613,7 @@ int dib0700_change_protocol(struct rc_dev *rc, u64 rc_type)
>
>        if (mutex_lock_interruptible(&d->usb_mutex) < 0) {
>                err("could not acquire lock");
> -               return 0;
> +               return -EINTR;
>        }
>
>        st->buf[0] = REQUEST_SET_RC;
> --
> 1.7.4.4
>
--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html