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authorWill Deacon <will.deacon@arm.com>2017-10-03 20:25:27 +0200
committerIngo Molnar <mingo@kernel.org>2017-10-10 11:50:18 +0200
commita8a217c22116eff6c120d753c9934089fb229af0 (patch)
treed56f1283ba7153f9ead9fb92c1a1794143c6e4a3 /include/asm-generic
parentlocking/rwsem, security/apparmor: Replace homebrew use of write_can_lock() wi... (diff)
downloadlinux-a8a217c22116eff6c120d753c9934089fb229af0.tar.xz
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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 'include/asm-generic')
-rw-r--r--include/asm-generic/qrwlock.h20
1 files changed, 0 insertions, 20 deletions
diff --git a/include/asm-generic/qrwlock.h b/include/asm-generic/qrwlock.h
index 7d026bf27713..50925327b0a8 100644
--- a/include/asm-generic/qrwlock.h
+++ b/include/asm-generic/qrwlock.h
@@ -53,24 +53,6 @@ extern void queued_read_lock_slowpath(struct qrwlock *lock, u32 cnts);
extern void queued_write_lock_slowpath(struct qrwlock *lock);
/**
- * queued_read_can_lock- would read_trylock() succeed?
- * @lock: Pointer to queue rwlock structure
- */
-static inline int queued_read_can_lock(struct qrwlock *lock)
-{
- return !(atomic_read(&lock->cnts) & _QW_WMASK);
-}
-
-/**
- * queued_write_can_lock- would write_trylock() succeed?
- * @lock: Pointer to queue rwlock structure
- */
-static inline int queued_write_can_lock(struct qrwlock *lock)
-{
- return !atomic_read(&lock->cnts);
-}
-
-/**
* queued_read_trylock - try to acquire read lock of a queue rwlock
* @lock : Pointer to queue rwlock structure
* Return: 1 if lock acquired, 0 if failed
@@ -169,8 +151,6 @@ static inline void queued_write_unlock(struct qrwlock *lock)
* Remapping rwlock architecture specific functions to the corresponding
* queue rwlock functions.
*/
-#define arch_read_can_lock(l) queued_read_can_lock(l)
-#define arch_write_can_lock(l) queued_write_can_lock(l)
#define arch_read_lock(l) queued_read_lock(l)
#define arch_write_lock(l) queued_write_lock(l)
#define arch_read_trylock(l) queued_read_trylock(l)