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, 9 insertions, 9 deletions

diff --git a/util/qemu-coroutine-lock.c b/util/qemu-coroutine-lock.c
index 5da5234155..36927b5f88 100644
--- a/util/qemu-coroutine-lock.c
+++ b/util/qemu-coroutine-lock.c
@@ -212,10 +212,10 @@ static void coroutine_fn qemu_co_mutex_lock_slowpath(AioContext *ctx,
     /* This is the "Responsibility Hand-Off" protocol; a lock() picks from
      * a concurrent unlock() the responsibility of waking somebody up.
      */
-    old_handoff = atomic_mb_read(&mutex->handoff);
+    old_handoff = qatomic_mb_read(&mutex->handoff);
     if (old_handoff &&
         has_waiters(mutex) &&
-        atomic_cmpxchg(&mutex->handoff, old_handoff, 0) == old_handoff) {
+        qatomic_cmpxchg(&mutex->handoff, old_handoff, 0) == old_handoff) {
         /* There can be no concurrent pops, because there can be only
          * one active handoff at a time.
          */
@@ -250,18 +250,18 @@ void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex)
      */
     i = 0;
 retry_fast_path:
-    waiters = atomic_cmpxchg(&mutex->locked, 0, 1);
+    waiters = qatomic_cmpxchg(&mutex->locked, 0, 1);
     if (waiters != 0) {
         while (waiters == 1 && ++i < 1000) {
-            if (atomic_read(&mutex->ctx) == ctx) {
+            if (qatomic_read(&mutex->ctx) == ctx) {
                 break;
             }
-            if (atomic_read(&mutex->locked) == 0) {
+            if (qatomic_read(&mutex->locked) == 0) {
                 goto retry_fast_path;
             }
             cpu_relax();
         }
-        waiters = atomic_fetch_inc(&mutex->locked);
+        waiters = qatomic_fetch_inc(&mutex->locked);
     }
 
     if (waiters == 0) {
@@ -288,7 +288,7 @@ void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex)
     mutex->ctx = NULL;
     mutex->holder = NULL;
     self->locks_held--;
-    if (atomic_fetch_dec(&mutex->locked) == 1) {
+    if (qatomic_fetch_dec(&mutex->locked) == 1) {
         /* No waiting qemu_co_mutex_lock().  Pfew, that was easy!  */
         return;
     }
@@ -311,7 +311,7 @@ void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex)
         }
 
         our_handoff = mutex->sequence;
-        atomic_mb_set(&mutex->handoff, our_handoff);
+        qatomic_mb_set(&mutex->handoff, our_handoff);
         if (!has_waiters(mutex)) {
             /* The concurrent lock has not added itself yet, so it
              * will be able to pick our handoff.
@@ -322,7 +322,7 @@ void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex)
         /* Try to do the handoff protocol ourselves; if somebody else has
          * already taken it, however, we're done and they're responsible.
          */
-        if (atomic_cmpxchg(&mutex->handoff, our_handoff, 0) != our_handoff) {
+        if (qatomic_cmpxchg(&mutex->handoff, our_handoff, 0) != our_handoff) {
             break;
         }
     }