diff options
| author | Syed Nayyar Waris <syednwaris@gmail.com> | 2020-03-16 15:50:06 +0300 |
|---|---|---|
| committer | Jonathan Cameron <Jonathan.Cameron@huawei.com> | 2020-06-14 16:44:32 +0300 |
| commit | 708d98932893cea609386cefdfd190f757f5a61c (patch) | |
| tree | 1300b2c06ce5eae822162ecd30af8ec4868077b2 /drivers/counter | |
| parent | 25f02d3242ab4d16d0cee2dec0d89cedb3747fa9 (diff) | |
| download | linux-708d98932893cea609386cefdfd190f757f5a61c.tar.xz | |
counter: 104-quad-8: Add lock guards - differential encoder
Add lock protection from race conditions to 104-quad-8 counter driver
for differential encoder status code changes. Mutex lock calls used for
protection.
Signed-off-by: Syed Nayyar Waris <syednwaris@gmail.com>
Fixes: 954ab5cc5f3e ("counter: 104-quad-8: Support Differential Encoder Cable Status")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Diffstat (limited to 'drivers/counter')
| -rw-r--r-- | drivers/counter/104-quad-8.c | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c index aa13708c2bc3..9364dc188f8f 100644 --- a/drivers/counter/104-quad-8.c +++ b/drivers/counter/104-quad-8.c @@ -1274,18 +1274,26 @@ static ssize_t quad8_signal_cable_fault_read(struct counter_device *counter, struct counter_signal *signal, void *private, char *buf) { - const struct quad8_iio *const priv = counter->priv; + struct quad8_iio *const priv = counter->priv; const size_t channel_id = signal->id / 2; - const bool disabled = !(priv->cable_fault_enable & BIT(channel_id)); + bool disabled; unsigned int status; unsigned int fault; - if (disabled) + mutex_lock(&priv->lock); + + disabled = !(priv->cable_fault_enable & BIT(channel_id)); + + if (disabled) { + mutex_unlock(&priv->lock); return -EINVAL; + } /* Logic 0 = cable fault */ status = inb(priv->base + QUAD8_DIFF_ENCODER_CABLE_STATUS); + mutex_unlock(&priv->lock); + /* Mask respective channel and invert logic */ fault = !(status & BIT(channel_id)); @@ -1317,6 +1325,8 @@ static ssize_t quad8_signal_cable_fault_enable_write( if (ret) return ret; + mutex_lock(&priv->lock); + if (enable) priv->cable_fault_enable |= BIT(channel_id); else @@ -1327,6 +1337,8 @@ static ssize_t quad8_signal_cable_fault_enable_write( outb(cable_fault_enable, priv->base + QUAD8_DIFF_ENCODER_CABLE_STATUS); + mutex_unlock(&priv->lock); + return len; } |