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>

1 files changed, 5 insertions, 5 deletions

diff --git a/include/qemu/rcu.h b/include/qemu/rcu.h
index 0e375eb..515d327 100644
--- a/include/qemu/rcu.h
+++ b/include/qemu/rcu.h
@@ -79,8 +79,8 @@ static inline void rcu_read_lock(void)
         return;
     }
 
-    ctr = atomic_read(&rcu_gp_ctr);
-    atomic_set(&p_rcu_reader->ctr, ctr);
+    ctr = qatomic_read(&rcu_gp_ctr);
+    qatomic_set(&p_rcu_reader->ctr, ctr);
 
     /* Write p_rcu_reader->ctr before reading RCU-protected pointers.  */
     smp_mb_placeholder();
@@ -100,12 +100,12 @@ static inline void rcu_read_unlock(void)
      * smp_mb_placeholder(), this ensures writes to p_rcu_reader->ctr
      * are sequentially consistent.
      */
-    atomic_store_release(&p_rcu_reader->ctr, 0);
+    qatomic_store_release(&p_rcu_reader->ctr, 0);
 
     /* Write p_rcu_reader->ctr before reading p_rcu_reader->waiting.  */
     smp_mb_placeholder();
-    if (unlikely(atomic_read(&p_rcu_reader->waiting))) {
-        atomic_set(&p_rcu_reader->waiting, false);
+    if (unlikely(qatomic_read(&p_rcu_reader->waiting))) {
+        qatomic_set(&p_rcu_reader->waiting, false);
         qemu_event_set(&rcu_gp_event);
     }
 }