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, 8 insertions, 7 deletions

diff --git a/block/block-backend.c b/block/block-backend.c
index 24dd0670d1..ce78d30794 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -1353,12 +1353,12 @@ int blk_make_zero(BlockBackend *blk, BdrvRequestFlags flags)
 
 void blk_inc_in_flight(BlockBackend *blk)
 {
-    atomic_inc(&blk->in_flight);
+    qatomic_inc(&blk->in_flight);
 }
 
 void blk_dec_in_flight(BlockBackend *blk)
 {
-    atomic_dec(&blk->in_flight);
+    qatomic_dec(&blk->in_flight);
     aio_wait_kick();
 }
 
@@ -1720,7 +1720,7 @@ void blk_drain(BlockBackend *blk)
 
     /* We may have -ENOMEDIUM completions in flight */
     AIO_WAIT_WHILE(blk_get_aio_context(blk),
-                   atomic_mb_read(&blk->in_flight) > 0);
+                   qatomic_mb_read(&blk->in_flight) > 0);
 
     if (bs) {
         bdrv_drained_end(bs);
@@ -1739,7 +1739,7 @@ void blk_drain_all(void)
         aio_context_acquire(ctx);
 
         /* We may have -ENOMEDIUM completions in flight */
-        AIO_WAIT_WHILE(ctx, atomic_mb_read(&blk->in_flight) > 0);
+        AIO_WAIT_WHILE(ctx, qatomic_mb_read(&blk->in_flight) > 0);
 
         aio_context_release(ctx);
     }
@@ -2346,6 +2346,7 @@ void blk_io_limits_update_group(BlockBackend *blk, const char *group)
 static void blk_root_drained_begin(BdrvChild *child)
 {
     BlockBackend *blk = child->opaque;
+    ThrottleGroupMember *tgm = &blk->public.throttle_group_member;
 
     if (++blk->quiesce_counter == 1) {
         if (blk->dev_ops && blk->dev_ops->drained_begin) {
@@ -2356,8 +2357,8 @@ static void blk_root_drained_begin(BdrvChild *child)
     /* Note that blk->root may not be accessible here yet if we are just
      * attaching to a BlockDriverState that is drained. Use child instead. */
 
-    if (atomic_fetch_inc(&blk->public.throttle_group_member.io_limits_disabled) == 0) {
-        throttle_group_restart_tgm(&blk->public.throttle_group_member);
+    if (qatomic_fetch_inc(&tgm->io_limits_disabled) == 0) {
+        throttle_group_restart_tgm(tgm);
     }
 }
 
@@ -2374,7 +2375,7 @@ static void blk_root_drained_end(BdrvChild *child, int *drained_end_counter)
     assert(blk->quiesce_counter);
 
     assert(blk->public.throttle_group_member.io_limits_disabled);
-    atomic_dec(&blk->public.throttle_group_member.io_limits_disabled);
+    qatomic_dec(&blk->public.throttle_group_member.io_limits_disabled);
 
     if (--blk->quiesce_counter == 0) {
         if (blk->dev_ops && blk->dev_ops->drained_end) {