[Qemu-devel] [PATCH v3 05/40] event_notifier: Make event_notifier_init_fd() #ifdef CONFIG_EVENTFD

[Markus Armbruster <armbru@redhat.com>]

Event notifiers are designed for eventfd(2).  They can fall back to
pipes, but according to Paolo, event_notifier_init_fd() really
requires the real thing, and should therefore be under #ifdef
CONFIG_EVENTFD.  Do that.

Its only user is ivshmem, which is currently CONFIG_POSIX.  Narrow it
to CONFIG_EVENTFD.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
---
 default-configs/pci.mak     | 2 +-
 util/event_notifier-posix.c | 6 ++++++
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/default-configs/pci.mak b/default-configs/pci.mak
index 4fa9a28..9c8bc68 100644
--- a/default-configs/pci.mak
+++ b/default-configs/pci.mak
@@ -36,5 +36,5 @@ CONFIG_SDHCI=y
 CONFIG_EDU=y
 CONFIG_VGA=y
 CONFIG_VGA_PCI=y
-CONFIG_IVSHMEM=$(CONFIG_POSIX)
+CONFIG_IVSHMEM=$(CONFIG_EVENTFD)
 CONFIG_ROCKER=y
diff --git a/util/event_notifier-posix.c b/util/event_notifier-posix.c
index 2e30e74..c9657a6 100644
--- a/util/event_notifier-posix.c
+++ b/util/event_notifier-posix.c
@@ -20,11 +20,17 @@
 #include <sys/eventfd.h>
 #endif
 
+#ifdef CONFIG_EVENTFD
+/*
+ * Initialize @e with existing file descriptor @fd.
+ * @fd must be a genuine eventfd object, emulation with pipe won't do.
+ */
 void event_notifier_init_fd(EventNotifier *e, int fd)
 {
     e->rfd = fd;
     e->wfd = fd;
 }
+#endif
 
 int event_notifier_init(EventNotifier *e, int active)
 {
-- 
2.4.3