diff options
| author | Hans Petter Selasky <hselasky@FreeBSD.org> | 2018-06-06 13:59:51 +0000 |
|---|---|---|
| committer | Hans Petter Selasky <hselasky@FreeBSD.org> | 2018-06-06 13:59:51 +0000 |
| commit | 23dcf4359ef57a3201bb838d7df5c542f6bc0651 (patch) | |
| tree | c1d8e59c95b310a9f88ef96a8e69b237a2bfe833 /sys/compat/linuxkpi/common/include/asm | |
| parent | 9e067b2256f429d7468ea4c7b152ce9bd59c930d (diff) | |
Implement the atomic_dec_if_positive() function in the LinuxKPI.
Submitted by: Johannes Lundberg <johalun0@gmail.com>
MFC after: 1 week
Sponsored by: Mellanox Technologies
Sponsored by: Limelight Networks
Notes
Notes:
svn path=/head/; revision=334712
Diffstat (limited to 'sys/compat/linuxkpi/common/include/asm')
| -rw-r--r-- | sys/compat/linuxkpi/common/include/asm/atomic.h | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/sys/compat/linuxkpi/common/include/asm/atomic.h b/sys/compat/linuxkpi/common/include/asm/atomic.h index 4b2610ca54f0..8a7ecdcf9d03 100644 --- a/sys/compat/linuxkpi/common/include/asm/atomic.h +++ b/sys/compat/linuxkpi/common/include/asm/atomic.h @@ -235,6 +235,22 @@ atomic_cmpxchg(atomic_t *v, int old, int new) __ret.val; \ }) +static inline int +atomic_dec_if_positive(atomic_t *v) +{ + int retval; + int curr; + + do { + curr = atomic_read(v); + retval = curr - 1; + if (unlikely(retval < 0)) + break; + } while (!likely(atomic_cmpset_int(&v->counter, curr, retval))); + + return (retval); +} + #define LINUX_ATOMIC_OP(op, c_op) \ static inline void atomic_##op(int i, atomic_t *v) \ { \ |