svn commit: r337374 - head/sys/compat/linuxkpi/common/include/asm
Hans Petter Selasky
hselasky at FreeBSD.org
Mon Aug 6 08:40:03 UTC 2018
Author: hselasky
Date: Mon Aug 6 08:40:02 2018
New Revision: 337374
URL: https://svnweb.freebsd.org/changeset/base/337374
Log:
Implement atomic_long_cmpxchg() function in the LinuxKPI.
Submitted by: Johannes Lundberg <johalun0 at gmail.com>
MFC after: 1 week
Sponsored by: Mellanox Technologies
Modified:
head/sys/compat/linuxkpi/common/include/asm/atomic-long.h
Modified: head/sys/compat/linuxkpi/common/include/asm/atomic-long.h
==============================================================================
--- head/sys/compat/linuxkpi/common/include/asm/atomic-long.h Mon Aug 6 08:35:16 2018 (r337373)
+++ head/sys/compat/linuxkpi/common/include/asm/atomic-long.h Mon Aug 6 08:40:02 2018 (r337374)
@@ -81,6 +81,21 @@ atomic_long_xchg(atomic_long_t *v, long val)
return atomic_swap_long(&v->counter, val);
}
+static inline long
+atomic_long_cmpxchg(atomic_long_t *v, long old, long new)
+{
+ long ret = old;
+
+ for (;;) {
+ if (atomic_cmpset_long(&v->counter, old, new))
+ break;
+ ret = READ_ONCE(v->counter);
+ if (ret != old)
+ break;
+ }
+ return (ret);
+}
+
static inline int
atomic_long_add_unless(atomic_long_t *v, long a, long u)
{
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