task_work: Decouple TIF_NOTIFY_SIGNAL and task_work

There are a small handful of reasons besides pending signals that the kernel might want to break out of interruptible sleeps. The flag TIF_NOTIFY_SIGNAL and the helpers that set and clear TIF_NOTIFY_SIGNAL provide that the infrastructure for breaking out of interruptible sleeps and entering the return to user space slow path for those cases. Expand tracehook_notify_signal inline in it's callers and remove it, which makes clear that TIF_NOTIFY_SIGNAL and task_work are separate concepts. Update the comment on set_notify_signal to more accurately describe it's purpose.

Eric W. Biederman committed 4 years ago

Commit 7c5d8fa1 parent 8ba62d34 files · +13 −17Browse files

Showing the changes to kernel (1 of 4 files). Show all

Unified · Split

kernel/entry/kvm.c+5−2

@@ -8,8 +8,11 @@ static int xfer_to_guest_mode_work(struct kvm_vcpu *vcpu, unsigned long ti_work) · 7 unmodified lines
8	8	do {
9	9	int ret;
10	10
11		− if (ti_work & (_TIF_SIGPENDING \| _TIF_NOTIFY_SIGNAL))
12		− tracehook_notify_signal();
	11	+ if (ti_work & (_TIF_SIGPENDING \| _TIF_NOTIFY_SIGNAL)) {
	12	+ clear_notify_signal();
	13	+ if (task_work_pending(current))
	14	+ task_work_run();
	15	+ }
13	16
14	17	if (ti_work & _TIF_SIGPENDING) {
15	18	kvm_handle_signal_exit(vcpu);