[PATCH 9/9] w1: w1_therm: leave the slaves of other families alone

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Josef Bacik <josef@toxicpanda.com>

The file therm_bulk_read belongs to the bus master.  Its callbacks walk
all the slaves of the bus and look at sl->family_data as if every slave
were a temperature sensor.  A 1-wire bus can carry other devices too:

- The family data of a slave which is driven by another driver, such as
  w1_ds2433, w1_ds250x, w1_ds28e04 or w1_ds28e17, is a structure of that
  driver.  bulk_read_support() takes whatever is at the offset of
  specific_functions for a pointer and dereferences it, and if the
  result happens not to be 0, the callbacks write the state of the
  conversion into that foreign structure.

- For a slave without family data, which is the case for most of the
  other drivers and for the default family, trigger_bulk_read() gives up
  with -ENODEV.  A single serial number chip on the bus is enough to
  make the bulk read unusable for all the sensors.

Only look at the slaves whose family is one of ours.  A bulk conversion
now works on a bus with other devices.

Fixes: 57c76221d5af ("w1_therm: adding bulk read support to trigger multiple conversion on bus")
Cc: stable <stable@kernel.org>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/w1/slaves/w1_therm.c | 37 +++++++++++++++++++++++--------------
 1 file changed, 23 insertions(+), 14 deletions(-)

diff --git a/drivers/w1/slaves/w1_therm.c b/drivers/w1/slaves/w1_therm.c
index 6db0b534b338..d8751b29f420 100644
--- a/drivers/w1/slaves/w1_therm.c
+++ b/drivers/w1/slaves/w1_therm.c
@@ -906,6 +906,19 @@ static inline bool bulk_read_support(struct w1_slave *sl)
 	return false;  /* No device family */
 }
 
+/**
+ * bulk_read_slave() - check if a slave of the bus takes part in a bulk read
+ * @sl: any slave on the list of the master
+ *
+ * The family data of the slaves of other families is none of our business.
+ *
+ * Return: true if it is one of our devices and supports bulk read
+ */
+static bool bulk_read_slave(struct w1_slave *sl)
+{
+	return device_family(sl) && sl->family_data && bulk_read_support(sl);
+}
+
 /**
  * conversion_time() - get the Tconv for the slave
  * @sl: device to get the conversion time
@@ -1497,9 +1510,7 @@ static int trigger_bulk_read(struct w1_master *dev_master)
 	 */
 	mutex_lock(&dev_master->list_mutex);
 	list_for_each_entry(sl, &dev_master->slist, w1_slave_entry) {
-		if (!sl->family_data)
-			goto error;
-		if (bulk_read_support(sl)) {
+		if (bulk_read_slave(sl)) {
 			int t_cur = conversion_time(sl);
 
 			t_conv = max(t_cur, t_conv);
@@ -1539,7 +1550,7 @@ static int trigger_bulk_read(struct w1_master *dev_master)
 			mutex_lock(&dev_master->list_mutex);
 			list_for_each_entry(sl,
 				&dev_master->slist, w1_slave_entry) {
-				if (bulk_read_support(sl))
+				if (bulk_read_slave(sl))
 					SLAVE_CONVERT_TRIGGERED(sl) = -1;
 			}
 			mutex_unlock(&dev_master->list_mutex);
@@ -1570,7 +1581,7 @@ static int trigger_bulk_read(struct w1_master *dev_master)
 	/* set a flag to register convsersion is done */
 	mutex_lock(&dev_master->list_mutex);
 	list_for_each_entry(sl, &dev_master->slist, w1_slave_entry) {
-		if (bulk_read_support(sl))
+		if (bulk_read_slave(sl))
 			SLAVE_CONVERT_TRIGGERED(sl) = 1;
 	}
 	mutex_unlock(&dev_master->list_mutex);
@@ -1940,16 +1951,14 @@ static ssize_t therm_bulk_read_show(struct device *device,
 
 	mutex_lock(&dev_master->list_mutex);
 	list_for_each_entry(sl, &dev_master->slist, w1_slave_entry) {
-		if (sl->family_data) {
-			if (bulk_read_support(sl)) {
-				if (SLAVE_CONVERT_TRIGGERED(sl) == -1) {
-					ret = -1;
-					goto show_result;
-				}
-				if (SLAVE_CONVERT_TRIGGERED(sl) == 1)
-					/* continue to check other slaves */
-					ret = 1;
+		if (bulk_read_slave(sl)) {
+			if (SLAVE_CONVERT_TRIGGERED(sl) == -1) {
+				ret = -1;
+				goto show_result;
 			}
+			if (SLAVE_CONVERT_TRIGGERED(sl) == 1)
+				/* continue to check other slaves */
+				ret = 1;
 		}
 	}
 show_result:

-- 
2.56.0