Since commit 60f481b970386 ("i40e: change flags to use 64 bits"),
the i40e driver uses cmpxchg64(). This causes mips:allmodconfig builds
to fail with
drivers/net/ethernet/intel/i40e/i40e_ethtool.c:
In function 'i40e_set_priv_flags':
drivers/net/ethernet/intel/i40e/i40e_ethtool.c:4443:2: error:
implicit declaration of function 'cmpxchg64'
Implement a poor-mans-version of cmpxchg64() to fix the problem for 32-bit
mips builds. The code is derived from sparc32, but only uses a single
spinlock.
Fixes: 60f481b970386 ("i40e: change flags to use 64 bits")
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
---
Compile-tested only.
arch/mips/include/asm/cmpxchg.h | 3 +++
arch/mips/kernel/cmpxchg.c | 17 +++++++++++++++++
2 files changed, 20 insertions(+)
diff --git a/arch/mips/include/asm/cmpxchg.h b/arch/mips/include/asm/cmpxchg.h
index 89e9fb7976fe..9f7b1df95b99 100644
--- a/arch/mips/include/asm/cmpxchg.h
+++ b/arch/mips/include/asm/cmpxchg.h
@@ -206,6 +206,9 @@ static inline unsigned long __cmpxchg(volatile void *ptr, unsigned long old,
#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
#ifndef CONFIG_SMP
#define cmpxchg64(ptr, o, n) cmpxchg64_local((ptr), (o), (n))
+#else
+u64 __cmpxchg_u64(u64 *ptr, u64 old, u64 new);
+#define cmpxchg64(ptr, old, new) __cmpxchg_u64(ptr, old, new)
#endif
#endif
diff --git a/arch/mips/kernel/cmpxchg.c b/arch/mips/kernel/cmpxchg.c
index 0b9535bc2c53..30216beb2334 100644
--- a/arch/mips/kernel/cmpxchg.c
+++ b/arch/mips/kernel/cmpxchg.c
@@ -9,6 +9,7 @@
*/
#include <linux/bitops.h>
+#include <linux/spinlock.h>
#include <asm/cmpxchg.h>
unsigned long __xchg_small(volatile void *ptr, unsigned long val, unsigned int size)
@@ -107,3 +108,19 @@ unsigned long __cmpxchg_small(volatile void *ptr, unsigned long old,
return old;
}
}
+
+static DEFINE_SPINLOCK(cmpxchg_lock);
+
+u64 __cmpxchg_u64(u64 *ptr, u64 old, u64 new)
+{
+ unsigned long flags;
+ u64 prev;
+
+ spin_lock_irqsave(&cmpxchg_lock, flags);
+ if ((prev = *ptr) == old)
+ *ptr = new;
+ spin_unlock_irqrestore(&cmpxchg_lock, flags);
+
+ return prev;
+}
+EXPORT_SYMBOL(__cmpxchg_u64);
--
2.7.4
