Daniel P. Berrangé <[email protected]> writes:
> A number of callers use monitor_cur() followed by !monitor_cur_is_qmp().
"A number of"? I can see just one:
int error_vprintf(const char *fmt, va_list ap)
{
Monitor *cur_mon = monitor_cur();
if (cur_mon && !monitor_cur_is_qmp()) {
return monitor_vprintf(cur_mon, fmt, ap);
}
return vfprintf(stderr, fmt, ap);
}
> This is undesirable because monitor_cur_is_qmp() will itself call
> monitor_cur() again, and monitor_cur() must acquire locks and do
> hash table lookups. Introducing a monitor_cur_hmp() helper will
> combine the two operations into one reducing cost.
This made me expect the patch replaces the undesirable uses. It does
not; the new function remains unused for now.
> Signed-off-by: Daniel P. Berrangé <[email protected]>
> ---
> include/monitor/monitor.h | 1 +
> monitor/monitor.c | 14 ++++++++++++++
> stubs/monitor-core.c | 5 +++++
> tests/unit/test-util-sockets.c | 1 +
> 4 files changed, 21 insertions(+)
>
> diff --git a/include/monitor/monitor.h b/include/monitor/monitor.h
> index 296690e1f1..c3b79b960a 100644
> --- a/include/monitor/monitor.h
> +++ b/include/monitor/monitor.h
> @@ -14,6 +14,7 @@ typedef struct MonitorOptions MonitorOptions;
> extern QemuOptsList qemu_mon_opts;
>
> Monitor *monitor_cur(void);
> +Monitor *monitor_cur_hmp(void);
> Monitor *monitor_set_cur(Coroutine *co, Monitor *mon);
> bool monitor_cur_is_qmp(void);
>
> diff --git a/monitor/monitor.c b/monitor/monitor.c
> index e1e5dbfcbe..cff502c53e 100644
> --- a/monitor/monitor.c
> +++ b/monitor/monitor.c
> @@ -84,6 +84,20 @@ Monitor *monitor_cur(void)
> return mon;
> }
>
> +Monitor *monitor_cur_hmp(void)
> +{
> + Monitor *mon;
> +
> + qemu_mutex_lock(&monitor_lock);
> + mon = g_hash_table_lookup(coroutine_mon, qemu_coroutine_self());
> + if (mon && monitor_is_qmp(mon)) {
> + mon = NULL;
> + }
> + qemu_mutex_unlock(&monitor_lock);
> +
> + return mon;
> +}
> +
> /**
> * Sets a new current monitor and returns the old one.
> *
> diff --git a/stubs/monitor-core.c b/stubs/monitor-core.c
> index b498a0f1af..1e0b11ec29 100644
> --- a/stubs/monitor-core.c
> +++ b/stubs/monitor-core.c
> @@ -7,6 +7,11 @@ Monitor *monitor_cur(void)
> return NULL;
> }
>
> +Monitor *monitor_cur_hmp(void)
> +{
> + return NULL;
> +}
> +
> bool monitor_cur_is_qmp(void)
> {
> return false;
> diff --git a/tests/unit/test-util-sockets.c b/tests/unit/test-util-sockets.c
> index bd48731ea2..d40813c682 100644
> --- a/tests/unit/test-util-sockets.c
> +++ b/tests/unit/test-util-sockets.c
> @@ -72,6 +72,7 @@ int monitor_get_fd(Monitor *mon, const char *fdname, Error
> **errp)
> * otherwise we get duplicate syms at link time.
> */
> Monitor *monitor_cur(void) { return cur_mon; }
> +Monitor *monitor_cur_hmp(void) { return cur_mon; }
@cur_mon is a fake here. Why do you make this fake monitor HMP? If we
somehow call error_vprintf(), it'll call monitor_vprintf(), which will
dereference the fake monitor. Best possible outcome would be an
immediate crash.
> bool monitor_cur_is_qmp(void) { return false; }
> Monitor *monitor_set_cur(Coroutine *co, Monitor *mon) { abort(); }
> int monitor_vprintf(Monitor *mon, const char *fmt, va_list ap) { abort(); }
