2024年4月1日 19:40，Alan Huang <mmpgouride@xxxxxxxxx> wrote： > > 2024年4月1日 00:16，Lai Jiangshan <jiangshanlai@xxxxxxxxx> wrote： >> >> On Sun, Mar 31, 2024 at 7:10 PM Joel Fernandes <joel@xxxxxxxxxxxxxxxxx> wrote: >>> >>> >>> >>>> On Mar 28, 2024, at 1:20 PM, Lai Jiangshan <jiangshanlai@xxxxxxxxx> wrote: >>>> >>>> From: Lai Jiangshan <jiangshan.ljs@xxxxxxxxxxxx> >>>> >>>> Prepare for arch-specific-defined rcu_preempt_depth_set(). >>>> >>>> No functionality change intended, but it has to be defined as a macro >>>> as rcupdate.h is a very low level header included from areas that don't >>>> even know about the task struct "current". >>> >>> Sorry I did not follow changelog. If some rcupdate.h includers do not know >>> about task_struct, how does adding a macro that uses current help? >>> >> >> Hello >> >> This is how macro works and it expands blindly based on tokens on the >> usage-sites. > > But ‘current’ still needs to be expanded at last, it seems to me that it only affects > the including order of the header files？ > > Or what am I missing? Get the missing part: if the user don’t need to use rcu_preempt_depth() and rcu_preempt_depth_set() but other parts of rcupdate.h, then the two has to be defined as a macro to avoid including linux/sched.h. Sorry for the bother. > >> >> And rcu_preempt_depth() & rcu_preempt_depth_set() are not universally >> used wrappers, the user can simply also include linux/sched.h to make >> they work. >> >> Thanks >> Lai
