From c231afa3ccf176490dcafc3666559e7567690e76 Mon Sep 17 00:00:00 2001 From: Christian Borntraeger Date: Tue, 4 Aug 2015 09:33:44 +0200 Subject: [PATCH] compiler.h: cast away attributes in WRITE_ONCE magic kernel build bot showed a warning triggered by commit 76695af20c01 ("locking, arch: use WRITE_ONCE()/READ_ONCE() in smp_store_release()/smp_load_acquire()"). Turns out that sparse does not like WRITE_ONCE accessing elements from the (sparse) rcu address space. fs/afs/inode.c:448:9: sparse: incorrect type in initializer (different address spaces) fs/afs/inode.c:448:9: expected struct afs_permits *__val fs/afs/inode.c:448:9: got void [noderef] * Solution is to force cast away the sparse attributes for the initializer of the union in WRITE_SAME. As this now gets too long, lets split the macro. Signed-off-by: Christian Borntraeger --- include/linux/compiler.h | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/include/linux/compiler.h b/include/linux/compiler.h index e08a6ae7c0a4..c836eb2dc44d 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -252,7 +252,12 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s ({ union { typeof(x) __val; char __c[1]; } __u; __read_once_size(&(x), __u.__c, sizeof(x)); __u.__val; }) #define WRITE_ONCE(x, val) \ - ({ union { typeof(x) __val; char __c[1]; } __u = { .__val = (val) }; __write_once_size(&(x), __u.__c, sizeof(x)); __u.__val; }) +({ \ + union { typeof(x) __val; char __c[1]; } __u = \ + { .__val = (__force typeof(x)) (val) }; \ + __write_once_size(&(x), __u.__c, sizeof(x)); \ + __u.__val; \ +}) /** * READ_ONCE_CTRL - Read a value heading a control dependency -- 2.39.2