On Mon, 13 Mar 2017, Gargi Sharma wrote:
> The IIO subsystem is redefining iio_dev->mlock to be used by
> the IIO core only for protecting device operating mode changes.
> ie. Changes between INDIO_DIRECT_MODE, INDIO_BUFFER_* modes.
>
> In this driver, mlock was being used to protect hardware state
> changes. Replace it with a lock in the devices global data.
> This was done using Coccinelle Script.
>
> @r1@
> identifier xxx_state;
> @@
> struct xxx_state {
> ...
> + struct mutex lock; /* protect sensor state */
> };
>
> @r2@
> expression e;
> @@
> - mutex_lock(e);
> + mutex_lock(&st->lock);
>
> @r3@
> expression e;
> @@
> - mutex_unlock(e);
> + mutex_unlock(&st->lock);
This rule is probably hjelpful in practice, but is very unsafe. Is there
any way that you can characterize the kind of structure you want to add a
new lock to? And likewise, what lock and unlock calls you want to
replace? And what is st?
julia
>
> Signed-off-by: Gargi Sharma <gs051095@xxxxxxxxx>
> ---
> drivers/staging/iio/adc/ad7280a.c | 21 +++++++++++----------
> 1 file changed, 11 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/staging/iio/adc/ad7280a.c b/drivers/staging/iio/adc/ad7280a.c
> index ee679ac..27a3ce3 100644
> --- a/drivers/staging/iio/adc/ad7280a.c
> +++ b/drivers/staging/iio/adc/ad7280a.c
> @@ -136,6 +136,7 @@ struct ad7280_state {
> unsigned char cb_mask[AD7280A_MAX_CHAIN];
>
> __be32 buf[2] ____cacheline_aligned;
> + struct mutex lock; /* protect sensor state */
> };
>
> static void ad7280_crc8_build_table(unsigned char *crc_tab)
> @@ -410,7 +411,7 @@ static ssize_t ad7280_store_balance_sw(struct device *dev,
> devaddr = this_attr->address >> 8;
> ch = this_attr->address & 0xFF;
>
> - mutex_lock(&indio_dev->mlock);
> + mutex_lock(&st->lock);
> if (readin)
> st->cb_mask[devaddr] |= 1 << (ch + 2);
> else
> @@ -418,7 +419,7 @@ static ssize_t ad7280_store_balance_sw(struct device *dev,
>
> ret = ad7280_write(st, devaddr, AD7280A_CELL_BALANCE,
> 0, st->cb_mask[devaddr]);
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&st->lock);
>
> return ret ? ret : len;
> }
> @@ -433,10 +434,10 @@ static ssize_t ad7280_show_balance_timer(struct device *dev,
> int ret;
> unsigned int msecs;
>
> - mutex_lock(&indio_dev->mlock);
> + mutex_lock(&st->lock);
> ret = ad7280_read(st, this_attr->address >> 8,
> this_attr->address & 0xFF);
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&st->lock);
>
> if (ret < 0)
> return ret;
> @@ -466,11 +467,11 @@ static ssize_t ad7280_store_balance_timer(struct device *dev,
> if (val > 31)
> return -EINVAL;
>
> - mutex_lock(&indio_dev->mlock);
> + mutex_lock(&st->lock);
> ret = ad7280_write(st, this_attr->address >> 8,
> this_attr->address & 0xFF,
> 0, (val & 0x1F) << 3);
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&st->lock);
>
> return ret ? ret : len;
> }
> @@ -655,7 +656,7 @@ static ssize_t ad7280_write_channel_config(struct device *dev,
>
> val = clamp(val, 0L, 0xFFL);
>
> - mutex_lock(&indio_dev->mlock);
> + mutex_lock(&st->lock);
> switch ((u32)this_attr->address) {
> case AD7280A_CELL_OVERVOLTAGE:
> st->cell_threshhigh = val;
> @@ -674,7 +675,7 @@ static ssize_t ad7280_write_channel_config(struct device *dev,
> ret = ad7280_write(st, AD7280A_DEVADDR_MASTER,
> this_attr->address, 1, val);
>
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&st->lock);
>
> return ret ? ret : len;
> }
> @@ -792,13 +793,13 @@ static int ad7280_read_raw(struct iio_dev *indio_dev,
>
> switch (m) {
> case IIO_CHAN_INFO_RAW:
> - mutex_lock(&indio_dev->mlock);
> + mutex_lock(&st->lock);
> if (chan->address == AD7280A_ALL_CELLS)
> ret = ad7280_read_all_channels(st, st->scan_cnt, NULL);
> else
> ret = ad7280_read_channel(st, chan->address >> 8,
> chan->address & 0xFF);
> - mutex_unlock(&indio_dev->mlock);
> + mutex_unlock(&st->lock);
>
> if (ret < 0)
> return ret;
> --
> 2.7.4
>
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