[PATCH 0/2] Prevent evaluation of WRITE_ONCE()

From: Andrea Parri
Date: Fri May 24 2019 - 06:38:55 EST


Hi all,

This all started when we realized that

atomic64_t v;
...
typeof(v.counter) my_val = atomic64_set(&v, VAL);

is a valid assignment on some architectures, but not on others [1]:
in particular, the assignment is valid on all architectures #define
-ing their atomic64_set() macro to WRITE_ONCE() (which is currently
evaluated).

Mark suggested to clean up all non-portable users of atomic*_set(),
and to prevent WRITE_ONCE() from being evaluated [2]; this resulted
in this first attempt/patchset based on Mark's atomics/type-cleanup
branch [3].

Cheers Andrea

[1] https://lkml.kernel.org/r/20190523083013.GA4616@andrea
[2] https://lkml.kernel.org/r/20190523141851.GA7523@xxxxxxxxxxxxxxxxxxxxxxxxx
[3] git://git.kernel.org/pub/scm/linux/kernel/git/mark/linux.git atomics/type-cleanup

Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Jorgen Hansen <jhansen@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Will Deacon <will.deacon@xxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxx>

Andrea Parri (2):
vmw_vmci: Clean up uses of atomic*_set()
compiler: Prevent evaluation of WRITE_ONCE()

include/linux/compiler.h | 5 ++---
include/linux/vmw_vmci_defs.h | 4 ++--
2 files changed, 4 insertions(+), 5 deletions(-)

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2.7.4