qemu/atomic.h: rename atomic_ to qatomic_

clang's C11 atomic_fetch_*() functions only take a C11 atomic type
pointer argument. QEMU uses direct types (int, etc) and this causes a
compiler error when a QEMU code calls these functions in a source file
that also included <stdatomic.h> via a system header file:

  $ CC=clang CXX=clang++ ./configure ... && make
  ../util/async.c:79:17: error: address argument to atomic operation must be a pointer to _Atomic type ('unsigned int *' invalid)

Avoid using atomic_*() names in QEMU's atomic.h since that namespace is
used by <stdatomic.h>. Prefix QEMU's APIs with 'q' so that atomic.h
and <stdatomic.h> can co-exist. I checked /usr/include on my machine and
searched GitHub for existing "qatomic_" users but there seem to be none.

This patch was generated using:

  $ git grep -h -o '\<atomic\(64\)\?_[a-z0-9_]\+' include/qemu/atomic.h | \
    sort -u >/tmp/changed_identifiers
  $ for identifier in $(</tmp/changed_identifiers); do
        sed -i "s%\<$identifier\>%q$identifier%g" \
            $(git grep -I -l "\<$identifier\>")
    done

I manually fixed line-wrap issues and misaligned rST tables.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20200923105646.47864-1-stefanha@redhat.com>

2 files changed, 2 insertions, 2 deletions

diff --git a/hw/s390x/s390-pci-bus.c b/hw/s390x/s390-pci-bus.c
index 92146a2..fb4cee8 100644
--- a/hw/s390x/s390-pci-bus.c
+++ b/hw/s390x/s390-pci-bus.c
@@ -650,7 +650,7 @@ static uint8_t set_ind_atomic(uint64_t ind_loc, uint8_t to_be_set)
     actual = *ind_addr;
     do {
         expected = actual;
-        actual = atomic_cmpxchg(ind_addr, expected, expected | to_be_set);
+        actual = qatomic_cmpxchg(ind_addr, expected, expected | to_be_set);
     } while (actual != expected);
     cpu_physical_memory_unmap((void *)ind_addr, len, 1, len);
 
diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c
index 8feb345..8d140dc 100644
--- a/hw/s390x/virtio-ccw.c
+++ b/hw/s390x/virtio-ccw.c
@@ -800,7 +800,7 @@ static uint8_t virtio_set_ind_atomic(SubchDev *sch, uint64_t ind_loc,
     actual = *ind_addr;
     do {
         expected = actual;
-        actual = atomic_cmpxchg(ind_addr, expected, expected | to_be_set);
+        actual = qatomic_cmpxchg(ind_addr, expected, expected | to_be_set);
     } while (actual != expected);
     trace_virtio_ccw_set_ind(ind_loc, actual, actual | to_be_set);
     cpu_physical_memory_unmap((void *)ind_addr, len, 1, len);