Re: [PATCH] locking: remove spin_lock_flags() etc

Waiman Long
2021-10-23T01:37:42Z

On 10/22/21 7:59 AM, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
>
> parisc, ia64 and powerpc32 are the only remaining architectures that
> provide custom arch_{spin,read,write}_lock_flags() functions, which are
> meant to re-enable interrupts while waiting for a spinlock.
>
> However, none of these can actually run into this codepath, because
> it is only called on architectures without CONFIG_GENERIC_LOCKBREAK,
> or when CONFIG_DEBUG_LOCK_ALLOC is set without CONFIG_LOCKDEP, and none
> of those combinations are possible on the three architectures.
>
> Going back in the git history, it appears that arch/mn10300 may have
> been able to run into this code path, but there is a good chance that
> it never worked. On the architectures that still exist, it was
> already impossible to hit back in 2008 after the introduction of
> CONFIG_GENERIC_LOCKBREAK, and possibly earlier.
>
> As this is all dead code, just remove it and the helper functions built
> around it. For arch/ia64, the inline asm could be cleaned up, but
> it seems safer to leave it untouched.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Does that mean we can also remove the GENERIC_LOCKBREAK config option
from the Kconfig files as well?

Cheers,
Longman