From bd3d245b0fef571f93504904df62b8865b1c0d34 Mon Sep 17 00:00:00 2001 From: Guan-Yu Lin Date: Wed, 1 Apr 2026 12:32:17 +0000 Subject: usb: core: use dedicated spinlock for offload state Replace the coarse USB device lock with a dedicated offload_lock spinlock to reduce contention during offload operations. Use offload_pm_locked to synchronize with PM transitions and replace the legacy offload_at_suspend flag. Optimize usb_offload_get/put by switching from auto-resume/suspend to pm_runtime_get_if_active(). This ensures offload state is only modified when the device is already active, avoiding unnecessary power transitions. Cc: stable Fixes: ef82a4803aab ("xhci: sideband: add api to trace sideband usage") Signed-off-by: Guan-Yu Lin Tested-by: Hailong Liu Acked-by: Mathias Nyman Link: https://patch.msgid.link/20260401123238.3790062-2-guanyulin@google.com Signed-off-by: Greg Kroah-Hartman --- include/linux/usb.h | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'include/linux/usb.h') diff --git a/include/linux/usb.h b/include/linux/usb.h index 04277af4bb9d..4aab20015851 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -21,6 +21,7 @@ #include /* for struct completion */ #include /* for current && schedule_timeout */ #include /* for struct mutex */ +#include /* for spinlock_t */ #include /* for runtime PM */ struct usb_device; @@ -636,8 +637,9 @@ struct usb3_lpm_parameters { * @do_remote_wakeup: remote wakeup should be enabled * @reset_resume: needs reset instead of resume * @port_is_suspended: the upstream port is suspended (L2 or U3) - * @offload_at_suspend: offload activities during suspend is enabled. + * @offload_pm_locked: prevents offload_usage changes during PM transitions. * @offload_usage: number of offload activities happening on this usb device. + * @offload_lock: protects offload_usage and offload_pm_locked * @slot_id: Slot ID assigned by xHCI * @l1_params: best effor service latency for USB2 L1 LPM state, and L1 timeout. * @u1_params: exit latencies for USB3 U1 LPM state, and hub-initiated timeout. @@ -726,8 +728,9 @@ struct usb_device { unsigned do_remote_wakeup:1; unsigned reset_resume:1; unsigned port_is_suspended:1; - unsigned offload_at_suspend:1; + unsigned offload_pm_locked:1; int offload_usage; + spinlock_t offload_lock; enum usb_link_tunnel_mode tunnel_mode; struct device_link *usb4_link; @@ -849,6 +852,7 @@ static inline void usb_mark_last_busy(struct usb_device *udev) int usb_offload_get(struct usb_device *udev); int usb_offload_put(struct usb_device *udev); bool usb_offload_check(struct usb_device *udev); +void usb_offload_set_pm_locked(struct usb_device *udev, bool locked); #else static inline int usb_offload_get(struct usb_device *udev) @@ -857,6 +861,8 @@ static inline int usb_offload_put(struct usb_device *udev) { return 0; } static inline bool usb_offload_check(struct usb_device *udev) { return false; } +static inline void usb_offload_set_pm_locked(struct usb_device *udev, bool locked) +{ } #endif extern int usb_disable_lpm(struct usb_device *udev); -- cgit v1.2.3