From a3ebdb6c423dff420168a3faf25c76e9e5f59258 Mon Sep 17 00:00:00 2001
From: Christoph Lameter <clameter@sgi.com>
Date: Tue, 18 Dec 2007 16:22:46 -0800
Subject: [PATCH] IA64: Slim down __clear_bit_unlock
__clear_bit_unlock does not need to perform atomic operations on the
variable. Avoid a cmpxchg and simply do a store with release semantics.
Add a barrier to be safe that the compiler does not do funky things.
Tony: Use intrinsic rather than inline assembler
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Acked-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
---
include/asm-ia64/bitops.h | 17 ++++++++++++++---
include/asm-ia64/gcc_intrin.h | 5 +++++
include/asm-ia64/intel_intrin.h | 3 +++
3 files changed, 22 insertions(+), 3 deletions(-)
diff --git a/include/asm-ia64/bitops.h b/include/asm-ia64/bitops.h
index a977affaebeca..a1b9719f5fbb7 100644
--- a/include/asm-ia64/bitops.h
+++ b/include/asm-ia64/bitops.h
@@ -124,10 +124,21 @@ clear_bit_unlock (int nr, volatile void *addr)
/**
* __clear_bit_unlock - Non-atomically clear a bit with release
*
- * This is like clear_bit_unlock, but the implementation may use a non-atomic
- * store (this one uses an atomic, however).
+ * This is like clear_bit_unlock, but the implementation uses a store
+ * with release semantics. See also __raw_spin_unlock().
*/
-#define __clear_bit_unlock clear_bit_unlock
+static __inline__ void
+__clear_bit_unlock(int nr, volatile void *addr)
+{
+ __u32 mask, new;
+ volatile __u32 *m;
+
+ m = (volatile __u32 *)addr + (nr >> 5);
+ mask = ~(1 << (nr & 31));
+ new = *m & mask;
+ barrier();
+ ia64_st4_rel_nta(m, new);
+}
/**
* __clear_bit - Clears a bit in memory (non-atomic version)
diff --git a/include/asm-ia64/gcc_intrin.h b/include/asm-ia64/gcc_intrin.h
index 4fb4e439b05c3..e58d3298fa109 100644
--- a/include/asm-ia64/gcc_intrin.h
+++ b/include/asm-ia64/gcc_intrin.h
@@ -191,6 +191,11 @@ register unsigned long ia64_r13 asm ("r13") __attribute_used__;
asm volatile ("ldf.fill %0=[%1]" :"=f"(__f__): "r"(x)); \
})
+#define ia64_st4_rel_nta(m, val) \
+({ \
+ asm volatile ("st4.rel.nta [%0] = %1\n\t" :: "r"(m), "r"(val)); \
+})
+
#define ia64_stfs(x, regnum) \
({ \
register double __f__ asm ("f"#regnum); \
diff --git a/include/asm-ia64/intel_intrin.h b/include/asm-ia64/intel_intrin.h
index d069b6acddce1..a520d103d8086 100644
--- a/include/asm-ia64/intel_intrin.h
+++ b/include/asm-ia64/intel_intrin.h
@@ -110,6 +110,9 @@
#define ia64_st4_rel __st4_rel
#define ia64_st8_rel __st8_rel
+/* FIXME: need st4.rel.nta intrinsic */
+#define ia64_st4_rel_nta __st4_rel
+
#define ia64_ld1_acq __ld1_acq
#define ia64_ld2_acq __ld2_acq
#define ia64_ld4_acq __ld4_acq
--
2.30.2