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Re: [PATCH] monitor: Use LOCK_GUARD macros
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [PATCH] monitor: Use LOCK_GUARD macros |
Date: |
Tue, 8 Sep 2020 15:43:00 +0100 |
User-agent: |
Mutt/1.14.6 (2020-07-11) |
* Markus Armbruster (armbru@redhat.com) wrote:
> "Dr. David Alan Gilbert (git)" <dgilbert@redhat.com> writes:
>
> > From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> >
> > Use the lock guard macros in monitor/misc.c - saves
> > a bunch of goto's, and a temporary variable, but mostly
> > because I prefer not having to release them in error paths.
> >
> > Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> > ---
> > monitor/misc.c | 62 ++++++++++++++++----------------------------------
> > 1 file changed, 20 insertions(+), 42 deletions(-)
> >
> > diff --git a/monitor/misc.c b/monitor/misc.c
> > index e847b58a8c..7f0b313d53 100644
> > --- a/monitor/misc.c
> > +++ b/monitor/misc.c
> > @@ -141,13 +141,13 @@ char *qmp_human_monitor_command(const char
> > *command_line, bool has_cpu_index,
> > handle_hmp_command(&hmp, command_line);
> > cur_mon = old_mon;
> >
> > - qemu_mutex_lock(&hmp.common.mon_lock);
> > - if (qstring_get_length(hmp.common.outbuf) > 0) {
> > - output = g_strdup(qstring_get_str(hmp.common.outbuf));
> > - } else {
> > - output = g_strdup("");
> > + WITH_QEMU_LOCK_GUARD(&hmp.common.mon_lock) {
> > + if (qstring_get_length(hmp.common.outbuf) > 0) {
> > + output = g_strdup(qstring_get_str(hmp.common.outbuf));
> > + } else {
> > + output = g_strdup("");
> > + }
> > }
> > - qemu_mutex_unlock(&hmp.common.mon_lock);
> >
> > out:
> > monitor_data_destroy(&hmp.common);
>
>
> Hardly an improvement here. I figure you want it for the sake of
> consistency.
Right, I was trying to do all the ones that weren't
worse; there's one case I left where it explicitly needed to do
something after the unlock.
> > @@ -1248,7 +1248,7 @@ void qmp_getfd(const char *fdname, Error **errp)
> > return;
> > }
> >
> > - qemu_mutex_lock(&cur_mon->mon_lock);
> > + QEMU_LOCK_GUARD(&cur_mon->mon_lock);
> > QLIST_FOREACH(monfd, &cur_mon->fds, next) {
> > if (strcmp(monfd->name, fdname) != 0) {
> > continue;
> > @@ -1256,7 +1256,6 @@ void qmp_getfd(const char *fdname, Error **errp)
> >
> > tmp_fd = monfd->fd;
> > monfd->fd = fd;
> > - qemu_mutex_unlock(&cur_mon->mon_lock);
> > /* Make sure close() is outside critical section */
> > close(tmp_fd);
> > return;
> > @@ -1267,7 +1266,6 @@ void qmp_getfd(const char *fdname, Error **errp)
> > monfd->fd = fd;
> >
> > QLIST_INSERT_HEAD(&cur_mon->fds, monfd, next);
> > - qemu_mutex_unlock(&cur_mon->mon_lock);
> > }
> >
>
> This one makes more sense.
>
> [More of the same...]
>
> Reviewed-by: Markus Armbruster <armbru@redhat.com>
Thanks.
Dave
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK