[PATCH 04/15] backports: add some more atomic functions

From: Johannes Berg <johannes@sipsolutions.net>
To: backports@vger.kernel.org
Cc: Johannes Berg <johannes.berg@intel.com>
Subject: [PATCH 04/15] backports: add some more atomic functions
Date: Fri, 21 Feb 2020 09:56:13 +0100	[thread overview]
Message-ID: <20200221095437.a7707d432cb0.Ib3fe021525950f62eba9fbebb67bd6374d4835e3@changeid> (raw)
In-Reply-To: <20200221085624.6213-1-johannes@sipsolutions.net>

From: Johannes Berg <johannes.berg@intel.com>

Some of the new fetch atomics are now required, add them by
using the _return ones and changing the value accordingly.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
---
 backport/backport-include/linux/atomic.h | 32 ++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/backport/backport-include/linux/atomic.h b/backport/backport-include/linux/atomic.h
index 9ceb586e864a..6669831ca8a9 100644
--- a/backport/backport-include/linux/atomic.h
+++ b/backport/backport-include/linux/atomic.h
@@ -60,4 +60,36 @@ static inline int atomic_fetch_add_unless(atomic_t *v, int a, int u)
 #endif
 #endif
 
+#ifndef __atomic_pre_full_fence
+#define __atomic_pre_full_fence         smp_mb__before_atomic
+#endif
+
+#ifndef __atomic_post_full_fence
+#define __atomic_post_full_fence        smp_mb__after_atomic
+#endif
+
+#if LINUX_VERSION_IS_LESS(4,8,0)
+static inline int
+atomic_fetch_add(int i, atomic_t *v)
+{
+	return atomic_add_return(i, v) - i;
+}
+
+static inline int
+atomic_fetch_sub(int i, atomic_t *v)
+{
+	return atomic_sub_return(i, v) + i;
+}
+#endif
+
+#ifndef atomic_fetch_add_relaxed
+#define atomic_fetch_add_relaxed atomic_fetch_add
+#endif
+
+#ifndef atomic_fetch_sub_relaxed
+#define atomic_fetch_sub_acquire atomic_fetch_sub
+#define atomic_fetch_sub_release atomic_fetch_sub
+#define atomic_fetch_sub_relaxed atomic_fetch_sub
+#endif
+
 #endif /* __BP_ATOMIC_H */
-- 
2.24.1

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