locking, compiler.h: Cast away attributes in the WRITE_ONCE() magic
authorChristian Borntraeger <borntraeger@de.ibm.com>
Tue, 4 Aug 2015 07:55:48 +0000 (09:55 +0200)
committerIngo Molnar <mingo@kernel.org>
Wed, 12 Aug 2015 09:58:58 +0000 (11:58 +0200)
commitba33034fffc1189d95301bd865f1c799256e72a2
tree2e840e27dadc8fe42ed8968487d1b3d6a3aca2e9
parentf52609fdabb1c726f8b9fdf64df3161781aa186e
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>
include/linux/compiler.h