[SPARC64]: Implement __raw_read_trylock()

generic__raw_read_trylock() just does a raw_read_lock() so that
isn't very useful.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 23 insertions, 1 deletions

diff --git a/include/asm-sparc64/spinlock.h b/include/asm-sparc64/spinlock.h
index ec85d12d73b9..508c416e9d6a 100644
--- a/include/asm-sparc64/spinlock.h
+++ b/include/asm-sparc64/spinlock.h
@@ -131,6 +131,28 @@ static void inline __read_lock(raw_rwlock_t *lock)
         : "memory");
 }
 
+static int inline __read_trylock(raw_rwlock_t *lock)
+{
+        int tmp1, tmp2;
+
+        __asm__ __volatile__ (
+"1:     ldsw            [%2], %0\n"
+"       brlz,a,pn       %0, 2f\n"
+"        mov            0, %0\n"
+"       add             %0, 1, %1\n"
+"       cas             [%2], %0, %1\n"
+"       cmp             %0, %1\n"
+"       membar          #StoreLoad | #StoreStore\n"
+"       bne,pn          %%icc, 1b\n"
+"        mov            1, %0\n"
+"2:"
+        : "=&r" (tmp1), "=&r" (tmp2)
+        : "r" (lock)
+        : "memory");
+
+        return tmp1;
+}
+
 static void inline __read_unlock(raw_rwlock_t *lock)
 {
         unsigned long tmp1, tmp2;
@@ -211,12 +233,12 @@ static int inline __write_trylock(raw_rwlock_t *lock)
 }
 
 #define __raw_read_lock(p)      __read_lock(p)
+#define __raw_read_trylock(p)   __read_trylock(p)
 #define __raw_read_unlock(p)    __read_unlock(p)
 #define __raw_write_lock(p)     __write_lock(p)
 #define __raw_write_unlock(p)   __write_unlock(p)
 #define __raw_write_trylock(p)  __write_trylock(p)
 
-#define __raw_read_trylock(lock)        generic__raw_read_trylock(lock)
 #define __raw_read_can_lock(rw)         (!((rw)->lock & 0x80000000UL))
 #define __raw_write_can_lock(rw)        (!(rw)->lock)