Spinlock init

Spinlock init

[Jack Stone]

Dear list,

can rwlock_init and spin_lock_init be used outside of functions declared
__init. The spinlock documentation suggests that it can't but I'd like
someone to confirm that.

Sorry if this has already been answered but I couldn't find anything on it.

Jack

Re: Spinlock init

[Roland Dreier]

 > can rwlock_init and spin_lock_init be used outside of functions declared
 > __init. The spinlock documentation suggests that it can't but I'd like
 > someone to confirm that.

Those function can be used in any function.  A function is declared
__init if it only runs during the kernel startup, so that the memory
holding the code for __init functions can be freed once startup is
done.  However, spin_lock_init() is just used to initialize a freshly
allocated spinlock, and spinlocks may be allocated at any time, even
long after the kernel is done starting up.  A quick look throught
kernel source code will show many, many examples where
spin_lock_init(), rwlock_init(), mutex_init(), etc. are called from
non-__init functions.


 - R.

Re: Spinlock init

[Jack Stone]

Roland Dreier wrote:
>  > can rwlock_init and spin_lock_init be used outside of functions declared
>  > __init. The spinlock documentation suggests that it can't but I'd like
>  > someone to confirm that.
> 
> Those function can be used in any function.  A function is declared
> __init if it only runs during the kernel startup, so that the memory
> holding the code for __init functions can be freed once startup is
> done.  However, spin_lock_init() is just used to initialize a freshly
> allocated spinlock, and spinlocks may be allocated at any time, even
> long after the kernel is done starting up.  A quick look throught
> kernel source code will show many, many examples where
> spin_lock_init(), rwlock_init(), mutex_init(), etc. are called from
> non-__init functions.

Exactly what I wanted to hear. Thank you very much.

Jack