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| author | Christian Borntraeger <borntraeger@de.ibm.com> | 2015-08-04 09:55:48 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-08-12 11:58:58 +0200 |
| commit | ba33034fffc1189d95301bd865f1c799256e72a2 (patch) | |
| tree | 2e840e27dadc8fe42ed8968487d1b3d6a3aca2e9 | |
| parent | Merge branch 'locking/arch-atomic' into locking/core, because it's ready for ... (diff) | |
| download | linux-ba33034fffc1189d95301bd865f1c799256e72a2.tar.xz linux-ba33034fffc1189d95301bd865f1c799256e72a2.zip | |
locking, compiler.h: Cast away attributes in the WRITE_ONCE() magic
The kernel build bot showed a new warning triggered by commit:
76695af20c01 ("locking, arch: use WRITE_ONCE()/READ_ONCE() in smp_store_release()/smp_load_acquire()")
because 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] <asn:4>*<noident>
Solution is to force cast away the sparse attributes for the initializer
of the union in WRITE_ONCE().
(And as this now gets too long, also split the macro into multiple lines.)
Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrey Konovalov <andreyknvl@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1438674948-38310-2-git-send-email-borntraeger@de.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | include/linux/compiler.h | 7 |
1 files changed, 6 insertions, 1 deletions
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 |