monitor: protect outbuf and mux_out with mutex

This lets the block layer emit QMP events from outside the I/O thread.

Reviewed-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
This commit is contained in:
Paolo Bonzini 2014-06-18 08:43:59 +02:00 committed by Luiz Capitulino
parent 9005b2a758
commit 6cff3e8594

View File

@ -191,13 +191,18 @@ typedef struct MonitorQAPIEventState {
struct Monitor {
CharDriverState *chr;
int mux_out;
int reset_seen;
int flags;
int suspend_cnt;
bool skip_flush;
QemuMutex out_lock;
QString *outbuf;
guint watch;
guint out_watch;
/* Read under either BQL or out_lock, written with BQL+out_lock. */
int mux_out;
ReadLineState *rs;
MonitorControl *mc;
CPUState *mon_cpu;
@ -270,17 +275,22 @@ int monitor_read_password(Monitor *mon, ReadLineFunc *readline_func,
}
}
static void monitor_flush_locked(Monitor *mon);
static gboolean monitor_unblocked(GIOChannel *chan, GIOCondition cond,
void *opaque)
{
Monitor *mon = opaque;
mon->watch = 0;
monitor_flush(mon);
qemu_mutex_lock(&mon->out_lock);
mon->out_watch = 0;
monitor_flush_locked(mon);
qemu_mutex_unlock(&mon->out_lock);
return FALSE;
}
void monitor_flush(Monitor *mon)
/* Called with mon->out_lock held. */
static void monitor_flush_locked(Monitor *mon)
{
int rc;
size_t len;
@ -307,18 +317,26 @@ void monitor_flush(Monitor *mon)
QDECREF(mon->outbuf);
mon->outbuf = tmp;
}
if (mon->watch == 0) {
mon->watch = qemu_chr_fe_add_watch(mon->chr, G_IO_OUT,
monitor_unblocked, mon);
if (mon->out_watch == 0) {
mon->out_watch = qemu_chr_fe_add_watch(mon->chr, G_IO_OUT,
monitor_unblocked, mon);
}
}
}
void monitor_flush(Monitor *mon)
{
qemu_mutex_lock(&mon->out_lock);
monitor_flush_locked(mon);
qemu_mutex_unlock(&mon->out_lock);
}
/* flush at every end of line */
static void monitor_puts(Monitor *mon, const char *str)
{
char c;
qemu_mutex_lock(&mon->out_lock);
for(;;) {
c = *str++;
if (c == '\0')
@ -328,9 +346,10 @@ static void monitor_puts(Monitor *mon, const char *str)
}
qstring_append_chr(mon->outbuf, c);
if (c == '\n') {
monitor_flush(mon);
monitor_flush_locked(mon);
}
}
qemu_mutex_unlock(&mon->out_lock);
}
void monitor_vprintf(Monitor *mon, const char *fmt, va_list ap)
@ -581,6 +600,7 @@ static void handle_user_command(Monitor *mon, const char *cmdline);
static void monitor_data_init(Monitor *mon)
{
memset(mon, 0, sizeof(Monitor));
qemu_mutex_init(&mon->out_lock);
mon->outbuf = qstring_new();
/* Use *mon_cmds by default. */
mon->cmd_table = mon_cmds;
@ -589,6 +609,7 @@ static void monitor_data_init(Monitor *mon)
static void monitor_data_destroy(Monitor *mon)
{
QDECREF(mon->outbuf);
qemu_mutex_destroy(&mon->out_lock);
}
char *qmp_human_monitor_command(const char *command_line, bool has_cpu_index,
@ -616,11 +637,13 @@ char *qmp_human_monitor_command(const char *command_line, bool has_cpu_index,
handle_user_command(&hmp, command_line);
cur_mon = old_mon;
qemu_mutex_lock(&hmp.out_lock);
if (qstring_get_length(hmp.outbuf) > 0) {
output = g_strdup(qstring_get_str(hmp.outbuf));
} else {
output = g_strdup("");
}
qemu_mutex_unlock(&hmp.out_lock);
out:
monitor_data_destroy(&hmp);
@ -5180,7 +5203,9 @@ static void monitor_event(void *opaque, int event)
switch (event) {
case CHR_EVENT_MUX_IN:
qemu_mutex_lock(&mon->out_lock);
mon->mux_out = 0;
qemu_mutex_unlock(&mon->out_lock);
if (mon->reset_seen) {
readline_restart(mon->rs);
monitor_resume(mon);
@ -5200,7 +5225,9 @@ static void monitor_event(void *opaque, int event)
} else {
mon->suspend_cnt++;
}
qemu_mutex_lock(&mon->out_lock);
mon->mux_out = 1;
qemu_mutex_unlock(&mon->out_lock);
break;
case CHR_EVENT_OPENED: