diff options
| author |   Will Deacon <will.deacon@arm.com> | 2018-04-26 11:34:16 +0100 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2018-04-27 09:48:45 +0200 |
| commit | 625e88be1f41b53cec55827c984e4a89ea8ee9f9 (patch) | |
| tree | f048dd06ff74ea19fc94f8a9aa844d41b5fb8a74 /include/asm-generic | |
| parent | locking/barriers: Introduce smp_cond_load_relaxed() and atomic_cond_read_relaxed() (diff) | |
| download | linux-dev-625e88be1f41b53cec55827c984e4a89ea8ee9f9.tar.xz linux-dev-625e88be1f41b53cec55827c984e4a89ea8ee9f9.zip | |
locking/qspinlock: Merge 'struct __qspinlock' into 'struct qspinlock'
'struct __qspinlock' provides a handy union of fields so that
subcomponents of the lockword can be accessed by name, without having to
manage shifts and masks explicitly and take endianness into account.
This is useful in qspinlock.h and also potentially in arch headers, so
move the 'struct __qspinlock' into 'struct qspinlock' and kill the extra
definition.
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Waiman Long <longman@redhat.com>
Acked-by: Boqun Feng <boqun.feng@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: paulmck@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/1524738868-31318-3-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/qspinlock_types.h | 32 |
1 files changed, 30 insertions, 2 deletions
diff --git a/include/asm-generic/qspinlock_types.h b/include/asm-generic/qspinlock_types.h index 034acd0c4956..0763f065b975 100644 --- a/include/asm-generic/qspinlock_types.h +++ b/include/asm-generic/qspinlock_types.h @@ -29,13 +29,41 @@ #endif typedef struct qspinlock { - atomic_t val; + union { + atomic_t val; + + /* + * By using the whole 2nd least significant byte for the + * pending bit, we can allow better optimization of the lock + * acquisition for the pending bit holder. + */ +#ifdef __LITTLE_ENDIAN + struct { + u8 locked; + u8 pending; + }; + struct { + u16 locked_pending; + u16 tail; + }; +#else + struct { + u16 tail; + u16 locked_pending; + }; + struct { + u8 reserved[2]; + u8 pending; + u8 locked; + }; +#endif + }; } arch_spinlock_t; /* * Initializier */ -#define __ARCH_SPIN_LOCK_UNLOCKED { ATOMIC_INIT(0) } +#define __ARCH_SPIN_LOCK_UNLOCKED { .val = ATOMIC_INIT(0) } /* * Bitfields in the atomic value: |