We want to add sleepable callbacks for hid_hw_raw_request() and hid_hw_output_report(), but we can not use a plain RCU for those.
Prepare for a SRCU so we can extend HID-BPF. This changes a little bit how hid_bpf_device_init() behaves, as it may now fail, so there is a tiny hid-core.c change to accommodate for this. Signed-off-by: Benjamin Tissoires <[email protected]> --- new in v2 --- drivers/hid/bpf/hid_bpf_dispatch.c | 6 +++++- drivers/hid/bpf/hid_bpf_struct_ops.c | 2 ++ drivers/hid/hid-core.c | 8 +++++++- include/linux/hid_bpf.h | 6 ++++-- 4 files changed, 18 insertions(+), 4 deletions(-) diff --git a/drivers/hid/bpf/hid_bpf_dispatch.c b/drivers/hid/bpf/hid_bpf_dispatch.c index 2df31decaac3..c026248e3d73 100644 --- a/drivers/hid/bpf/hid_bpf_dispatch.c +++ b/drivers/hid/bpf/hid_bpf_dispatch.c @@ -506,13 +506,17 @@ void hid_bpf_destroy_device(struct hid_device *hdev) hdev->bpf.destroyed = true; __hid_bpf_ops_destroy_device(hdev); + + synchronize_srcu(&hdev->bpf.srcu); + cleanup_srcu_struct(&hdev->bpf.srcu); } EXPORT_SYMBOL_GPL(hid_bpf_destroy_device); -void hid_bpf_device_init(struct hid_device *hdev) +int hid_bpf_device_init(struct hid_device *hdev) { INIT_LIST_HEAD(&hdev->bpf.prog_list); mutex_init(&hdev->bpf.prog_list_lock); + return init_srcu_struct(&hdev->bpf.srcu); } EXPORT_SYMBOL_GPL(hid_bpf_device_init); diff --git a/drivers/hid/bpf/hid_bpf_struct_ops.c b/drivers/hid/bpf/hid_bpf_struct_ops.c index 8063db1c8d62..d34731a1b457 100644 --- a/drivers/hid/bpf/hid_bpf_struct_ops.c +++ b/drivers/hid/bpf/hid_bpf_struct_ops.c @@ -214,6 +214,7 @@ static int hid_bpf_reg(void *kdata) list_add_rcu(&ops->list, &hdev->bpf.prog_list); else list_add_tail_rcu(&ops->list, &hdev->bpf.prog_list); + synchronize_srcu(&hdev->bpf.srcu); out_unlock: mutex_unlock(&hdev->bpf.prog_list_lock); @@ -244,6 +245,7 @@ static void hid_bpf_unreg(void *kdata) mutex_lock(&hdev->bpf.prog_list_lock); list_del_rcu(&ops->list); + synchronize_srcu(&hdev->bpf.srcu); reconnect = hdev->bpf.rdesc_ops == ops; if (reconnect) diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index 0775a32f5272..ad08289752da 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -2875,9 +2875,15 @@ struct hid_device *hid_allocate_device(void) mutex_init(&hdev->ll_open_lock); kref_init(&hdev->ref); - hid_bpf_device_init(hdev); + ret = hid_bpf_device_init(hdev); + if (ret) + goto out_err; return hdev; + +out_err: + hid_destroy_device(hdev); + return ERR_PTR(ret); } EXPORT_SYMBOL_GPL(hid_allocate_device); diff --git a/include/linux/hid_bpf.h b/include/linux/hid_bpf.h index a54741db0415..f93845de5cac 100644 --- a/include/linux/hid_bpf.h +++ b/include/linux/hid_bpf.h @@ -5,6 +5,7 @@ #include <linux/bpf.h> #include <linux/mutex.h> +#include <linux/srcu.h> #include <uapi/linux/hid.h> struct hid_device; @@ -145,6 +146,7 @@ struct hid_bpf { struct hid_bpf_ops *rdesc_ops; struct list_head prog_list; struct mutex prog_list_lock; /* protects prog_list update */ + struct srcu_struct srcu; /* protects prog_list read-only access */ }; #ifdef CONFIG_HID_BPF @@ -153,7 +155,7 @@ u8 *dispatch_hid_bpf_device_event(struct hid_device *hid, enum hid_report_type t int hid_bpf_connect_device(struct hid_device *hdev); void hid_bpf_disconnect_device(struct hid_device *hdev); void hid_bpf_destroy_device(struct hid_device *hid); -void hid_bpf_device_init(struct hid_device *hid); +int hid_bpf_device_init(struct hid_device *hid); u8 *call_hid_bpf_rdesc_fixup(struct hid_device *hdev, u8 *rdesc, unsigned int *size); #else /* CONFIG_HID_BPF */ static inline u8 *dispatch_hid_bpf_device_event(struct hid_device *hid, enum hid_report_type type, @@ -162,7 +164,7 @@ static inline u8 *dispatch_hid_bpf_device_event(struct hid_device *hid, enum hid static inline int hid_bpf_connect_device(struct hid_device *hdev) { return 0; } static inline void hid_bpf_disconnect_device(struct hid_device *hdev) {} static inline void hid_bpf_destroy_device(struct hid_device *hid) {} -static inline void hid_bpf_device_init(struct hid_device *hid) {} +static inline int hid_bpf_device_init(struct hid_device *hid) { return 0; } #define call_hid_bpf_rdesc_fixup(_hdev, _rdesc, _size) \ ((u8 *)kmemdup(_rdesc, *(_size), GFP_KERNEL)) -- 2.44.0
