mm: spinlock tree_lock

mapping->tree_lock has no read lockers.  convert the lock from an rwlock
to a spinlock.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/include/asm-arm/cacheflush.h b/include/asm-arm/cacheflush.h
index 70b0fe724b62..03cf1ee977b7 100644
--- a/include/asm-arm/cacheflush.h
+++ b/include/asm-arm/cacheflush.h
@@ -424,9 +424,9 @@ static inline void flush_anon_page(struct vm_area_struct *vma,
 }
 
 #define flush_dcache_mmap_lock(mapping) \
-        write_lock_irq(&(mapping)->tree_lock)
+        spin_lock_irq(&(mapping)->tree_lock)
 #define flush_dcache_mmap_unlock(mapping) \
-        write_unlock_irq(&(mapping)->tree_lock)
+        spin_unlock_irq(&(mapping)->tree_lock)
 
 #define flush_icache_user_range(vma,page,addr,len) \
         flush_dcache_page(page)