On 12/27/21 12:52 PM, Greg Kroah-Hartman wrote:
On Mon, Dec 27, 2021 at 12:34:28PM +0100, Lars-Peter Clausen wrote:
On 12/27/21 12:02 PM, Greg Kroah-Hartman wrote:
On Mon, Dec 27, 2021 at 10:45:07AM +0100, Uwe Kleine-König wrote:
For now this just wraps accessing struct counter_device::priv. However
this is about to change and converting drivers to this helper
individually makes fixing device lifetime issues result in easier to
review patches.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
---
drivers/counter/counter-core.c | 12 ++++++++++++
include/linux/counter.h | 2 ++
2 files changed, 14 insertions(+)
diff --git a/drivers/counter/counter-core.c b/drivers/counter/counter-core.c
index f053a43c6c04..00c41f28c101 100644
--- a/drivers/counter/counter-core.c
+++ b/drivers/counter/counter-core.c
@@ -45,6 +45,18 @@ static struct bus_type counter_bus_type = {
static dev_t counter_devt;
+/**
+ * counter_priv - access counter device private data
+ * @counter: counter device
+ *
+ * Get the counter device private data
+ */
+void *counter_priv(const struct counter_device *const counter)
+{
+ return counter->priv;
+}
+EXPORT_SYMBOL_GPL(counter_priv);
Shouldn't this be usin gdev_get_drvdata() and using the private data
pointer that is already on the struct device structure itself? The void
*priv; should be dropped from struct counter_device entirely.
Oh ick, I just now looked at 'struct counter_device', there are other
reference counting issues in there (hint, struct cdev has a reference
count...) But that's independent of this patch series...
This is not a problem. The struct cdev holds a reference to the struct dev.
This allows them to use the same allocation. As long as there is a reference
to the cdev there will be a reference to the dev and the memory will be kept
alive.
Ick, a cdev shouldn't be doing stuff like that, but I see how people
like to use it that way :(
Can you explain why cdev shouldn't be doing that? This commit has some
backstory why this is done
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=233ed09d7fdacf592ee91e6c97ce5f4364fbe7c0
