---

yaml --- r: 374271 b: refs/heads/master c: f21dda0 h: refs/heads/master i: 374269: 6eb0789 374267: 896fcda 374263: fb1a54b 374255: 59af2cd 374239: 8a2a100 374207: 72b2e4d 374143: dbcdd99 374015: 4bed1b9 373759: aff92e1 v: v3
git-mirror · May 6, 2013 · 6e6a6ef · 6e6a6ef
1 parent f84daa6
commit 6e6a6ef
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Showing 3 changed files with 25 additions and 1 deletion.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: bbbfde782084b4f0d85ddffb88f1cf4650ff40e4
+refs/heads/master: f21dda025ab00da197ac30b6c6690c380d838683
diff --git a/trunk/arch/parisc/Kconfig b/trunk/arch/parisc/Kconfig
@@ -13,6 +13,7 @@ config PARISC
 	select BUG
 	select HAVE_PERF_EVENTS
 	select GENERIC_ATOMIC64 if !64BIT
+	select ARCH_HAS_ATOMIC64_DEC_IF_POSITIVE
 	select HAVE_GENERIC_HARDIRQS
 	select BROKEN_RODATA
 	select GENERIC_IRQ_PROBE

diff --git a/trunk/arch/parisc/include/asm/atomic.h b/trunk/arch/parisc/include/asm/atomic.h
@@ -229,6 +229,29 @@ static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u)
 
 #define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0)
 
+/*
+ * atomic64_dec_if_positive - decrement by 1 if old value positive
+ * @v: pointer of type atomic_t
+ *
+ * The function returns the old value of *v minus 1, even if
+ * the atomic variable, v, was not decremented.
+ */
+static inline long atomic64_dec_if_positive(atomic64_t *v)
+{
+	long c, old, dec;
+	c = atomic64_read(v);
+	for (;;) {
+		dec = c - 1;
+		if (unlikely(dec < 0))
+			break;
+		old = atomic64_cmpxchg((v), c, dec);
+		if (likely(old == c))
+			break;
+		c = old;
+	}
+	return dec;
+}
+
 #endif /* !CONFIG_64BIT */