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 <vivek.gautam@xxxxxxxxxxxxxx> Suggested-by: Lukas Wunner <lukas@xxxxxxxxx> --- 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. [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) /** * struct device_link - Device link representation. -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
