Harald, Am 02.12.2014 um 11:07 schrieb Harald Geyer: > Hi Richard, > > thanks for the patch. Comments inline. > > Richard Weinberger writes: >> Protect the read function from concurrent reads. >> >> Signed-off-by: Richard Weinberger <[email protected]> >> --- >> drivers/iio/humidity/dht11.c | 19 ++++++++++++++----- >> 1 file changed, 14 insertions(+), 5 deletions(-) >> >> diff --git a/drivers/iio/humidity/dht11.c b/drivers/iio/humidity/dht11.c >> index 623c145..7636e66 100644 >> --- a/drivers/iio/humidity/dht11.c >> +++ b/drivers/iio/humidity/dht11.c > > #include <linux/mutex.h> > >> @@ -57,6 +57,7 @@ struct dht11 { >> int irq; >> >> struct completion completion; >> + struct mutex lock; >> >> s64 timestamp; >> int temperature; >> @@ -146,16 +147,17 @@ static int dht11_read_raw(struct iio_dev *iio_dev, >> int ret; >> >> if (dht11->timestamp + DHT11_DATA_VALID_TIME < iio_get_time_ns()) { >> + mutex_lock(&dht11->lock); > > Move the locking out of the if statement.
Care to explain why? But I found another issue in my patch. The "dht11->num_edges = -1;" before "return ret" needs to go into the locked area. Will send an updated version soon. > BTW, it seems that there is already locking around read_raw() in the > in-kernel consumer interface but not in the sysfs interface. Is there > any reason for this difference? Dunno. :-) Thanks, //richard -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
