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authorWill Deacon <will.deacon@arm.com>2017-10-03 19:25:27 +0100
committerIngo Molnar <mingo@kernel.org>2017-10-10 11:50:18 +0200
commita8a217c22116eff6c120d753c9934089fb229af0 (patch)
treed56f1283ba7153f9ead9fb92c1a1794143c6e4a3 /arch/metag
parent26c4eb192c6224e5297496cead36404b62fb071b (diff)
downloadlinux-a8a217c22116eff6c120d753c9934089fb229af0.tar.bz2
locking/core: Remove {read,spin,write}_can_lock()
Outside of the locking code itself, {read,spin,write}_can_lock() have no users in tree. Apparmor (the last remaining user of write_can_lock()) got moved over to lockdep by the previous patch. This patch removes the use of {read,spin,write}_can_lock() from the BUILD_LOCK_OPS macro, deferring to the trylock operation for testing the lock status, and subsequently removes the unused macros altogether. They aren't guaranteed to work in a concurrent environment and can give incorrect results in the case of qrwlock. Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: paulmck@linux.vnet.ibm.com Link: http://lkml.kernel.org/r/1507055129-12300-2-git-send-email-will.deacon@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/metag')
-rw-r--r--arch/metag/include/asm/spinlock_lnkget.h30
-rw-r--r--arch/metag/include/asm/spinlock_lock1.h20
2 files changed, 0 insertions, 50 deletions
diff --git a/arch/metag/include/asm/spinlock_lnkget.h b/arch/metag/include/asm/spinlock_lnkget.h
index ad8436feed8d..6a932a952d53 100644
--- a/arch/metag/include/asm/spinlock_lnkget.h
+++ b/arch/metag/include/asm/spinlock_lnkget.h
@@ -136,21 +136,6 @@ static inline void arch_write_unlock(arch_rwlock_t *rw)
: "memory");
}
-/* write_can_lock - would write_trylock() succeed? */
-static inline int arch_write_can_lock(arch_rwlock_t *rw)
-{
- int ret;
-
- asm volatile ("LNKGETD %0, [%1]\n"
- "CMP %0, #0\n"
- "MOV %0, #1\n"
- "XORNZ %0, %0, %0\n"
- : "=&d" (ret)
- : "da" (&rw->lock)
- : "cc");
- return ret;
-}
-
/*
* Read locks are a bit more hairy:
* - Exclusively load the lock value.
@@ -224,21 +209,6 @@ static inline int arch_read_trylock(arch_rwlock_t *rw)
return tmp;
}
-/* read_can_lock - would read_trylock() succeed? */
-static inline int arch_read_can_lock(arch_rwlock_t *rw)
-{
- int tmp;
-
- asm volatile ("LNKGETD %0, [%1]\n"
- "CMP %0, %2\n"
- "MOV %0, #1\n"
- "XORZ %0, %0, %0\n"
- : "=&d" (tmp)
- : "da" (&rw->lock), "bd" (0x80000000)
- : "cc");
- return tmp;
-}
-
#define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
#define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
diff --git a/arch/metag/include/asm/spinlock_lock1.h b/arch/metag/include/asm/spinlock_lock1.h
index c630444cffe9..8ae12bfc8ad8 100644
--- a/arch/metag/include/asm/spinlock_lock1.h
+++ b/arch/metag/include/asm/spinlock_lock1.h
@@ -104,16 +104,6 @@ static inline void arch_write_unlock(arch_rwlock_t *rw)
rw->lock = 0;
}
-/* write_can_lock - would write_trylock() succeed? */
-static inline int arch_write_can_lock(arch_rwlock_t *rw)
-{
- unsigned int ret;
-
- barrier();
- ret = rw->lock;
- return (ret == 0);
-}
-
/*
* Read locks are a bit more hairy:
* - Exclusively load the lock value.
@@ -171,14 +161,4 @@ static inline int arch_read_trylock(arch_rwlock_t *rw)
return (ret < 0x80000000);
}
-/* read_can_lock - would read_trylock() succeed? */
-static inline int arch_read_can_lock(arch_rwlock_t *rw)
-{
- unsigned int ret;
-
- barrier();
- ret = rw->lock;
- return (ret < 0x80000000);
-}
-
#endif /* __ASM_SPINLOCK_LOCK1_H */