Hi Rafael,
On 5/30/2018 4:29 PM, Rafael J. Wysocki wrote:
On 5/30/2018 11:57 AM, Vivek Gautam wrote:
When using the device links without the consumers or
suppliers maintaining pointers to these links, a flag can
help in autoremoving the links on supplier driver unbind.
We remove these links only when the supplier's link to its
consumers has gone in DL_STATE_SUPPLIER_UNBIND state.
Signed-off-by: Vivek Gautam <[email protected]>
Suggested-by: Lukas Wunner <[email protected]>
---
Lukas, as suggested in the thread [1] this change adds additional flag
to autoremove device links on supplier unbind.
For arm-smmu, we want to _not_ keep references to the device links
added between arm-smmu, and consumer devices.
Robin also pointed to [2] the need to autoremove the device link on
supplier unbind rather than consumer unbind.
Please CC device links patches to linux-pm.
Thanks for the quick review. Sure, will keep this noted from now on.
[1] https://lkml.org/lkml/2018/3/14/390
[2] https://lkml.org/lkml/2018/5/21/381
drivers/base/core.c | 10 ++++++++++
include/linux/device.h | 2 ++
2 files changed, 12 insertions(+)
diff --git a/drivers/base/core.c b/drivers/base/core.c
index b610816eb887..52c7222bb3c4 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -490,6 +490,16 @@ void device_links_driver_cleanup(struct device
*dev)
WARN_ON(link->flags & DL_FLAG_AUTOREMOVE);
WARN_ON(link->status != DL_STATE_SUPPLIER_UNBIND);
+
+ /*
+ * autoremove the links between this @dev and its consumer
+ * devices that are not active, i.e. where the link state
+ * has moved to DL_STATE_SUPPLIER_UNBIND.
+ */
+ if (link->status == DL_STATE_SUPPLIER_UNBIND &&
+ link->flags & DL_FLAG_AUTOREMOVE_S)
+ kref_put(&link->kref, __device_link_del);
+
WRITE_ONCE(link->status, DL_STATE_DORMANT);
}
diff --git a/include/linux/device.h b/include/linux/device.h
index 477956990f5e..6033bf58453d 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -779,11 +779,13 @@ enum device_link_state {
* AUTOREMOVE: Remove this link automatically on consumer driver
unbind.
* PM_RUNTIME: If set, the runtime PM framework will use this link.
* RPM_ACTIVE: Run pm_runtime_get_sync() on the supplier during
link creation.
+ * AUTOREMOVE_S: Remove this link automatically on supplier driver
unbind.
*/
#define DL_FLAG_STATELESS BIT(0)
#define DL_FLAG_AUTOREMOVE BIT(1)
#define DL_FLAG_PM_RUNTIME BIT(2)
#define DL_FLAG_RPM_ACTIVE BIT(3)
+#define DL_FLAG_AUTOREMOVE_S BIT(4)
Couldn't you invent a better name for this one?
Frankly, I wanted to have something like DL_FLAG_AUTOREMOVE_SUPPLIER,
but that
felt a bit too long considering other flags.
Can you please consider suggesting a concise name?
Regards
Vivek
/**
* struct device_link - Device link representation.
