interconnect: Add locking in icc_set_tag()

We must ensure that the tag is not changed while we aggregate the
requests. Currently the icc_set_tag() is not using any locks and this
may cause the values to be aggregated incorrectly. Fix this by acquiring
the icc_lock while we set the tag.

Link: https://lore.kernel.org/lkml/20191018141750.17032-1-georgi.djakov@linaro.org/
Fixes: 127ab2cc ("interconnect: Add support for path tags")
Reviewed-by: Bjorn Andersson <bjorn.andersson@linaro.org>
Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>

drivers/interconnect/core.c

@@ -405,8 +405,12 @@ void icc_set_tag(struct icc_path *path, u32 tag)
 	if (!path)
 		return;
 
+	mutex_lock(&icc_lock);
+
 	for (i = 0; i < path->num_nodes; i++)
 		path->reqs[i].tag = tag;
+
+	mutex_unlock(&icc_lock);
 }
 EXPORT_SYMBOL_GPL(icc_set_tag);