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

From: Waiman Long
Date: Fri Oct 22 2021 - 21:37:48 EST


On 10/22/21 7:59 AM, Arnd Bergmann wrote:
From: Arnd Bergmann <arnd@xxxxxxxx>

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@xxxxxxxx>

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

Cheers,
Longman