Re: [PATCH V3] binder: ipc namespace support for android binder

[Davidlohr Bueso]

On Thu, 08 Nov 2018, chouryzhou(??????) wrote:

> +#ifdef CONFIG_ANDROID_BINDER_IPC
> +       /* next fields are for binder */
> +       struct mutex      binder_procs_lock;
> +       struct hlist_head binder_procs;
> +       struct hlist_head binder_contexts;
> +#endif

Now, I took a look at how the binder_procs list is used; and no, what
follows isn't really related to this patch, but a general observation.

I think that a mutex is also an overkill and you might wanna replace it
with a spinlock/rwlock. Can anything block while holding the binder_procs_lock?
I don't see anything... you mainly need it for consulting the hlist calling
print_binder_proc[_stat]() - which will take the proc->inner_lock anyway, so
no blocking there. Also, if this is perhaps because of long hold times, dunno,
the rb_first_cached primitive might reduce some of it, although I don't know
how big the rbtrees in binder can get and if it matters at all.

Anyway, that said and along with addressing Todd's comments, the ipc/ bits look
good. Feel free to add my:

Reviewed-by: Davidlohr Bueso <dave@xxxxxxxxxxxx>

Thanks,
Davidlohr