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locking: Remove spin_lock_flags() etc

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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>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Helge Deller <deller@gmx.de>  # parisc
Link: https://lore.kernel.org/r/20211022120058.1031690-1-arnd@kernel.org
This commit is contained in:
Arnd Bergmann
2021-10-22 13:59:38 +02:00
committed by Peter Zijlstra
parent 5197fcd09a
commit f98a3dccfc
12 changed files with 9 additions and 125 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
arch/s390/include/asm/spinlock.h
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@@ -67,14 +67,6 @@ static inline void arch_spin_lock(arch_spinlock_t *lp)
arch_spin_lock_wait(lp);
}
static inline void arch_spin_lock_flags(arch_spinlock_t *lp,
unsigned long flags)
{
if (!arch_spin_trylock_once(lp))
arch_spin_lock_wait(lp);
}
#define arch_spin_lock_flags arch_spin_lock_flags
static inline int arch_spin_trylock(arch_spinlock_t *lp)
{
if (!arch_spin_trylock_once(lp))