[dm-devel] [PATCH 07/23] multipathd: move conf destruction into separate function
Benjamin Marzinski
bmarzins at redhat.com
Mon Sep 28 18:03:12 UTC 2020
On Thu, Sep 24, 2020 at 03:40:38PM +0200, mwilck at suse.com wrote:
> From: Martin Wilck <mwilck at suse.com>
>
> Also removing the comment about dlog() and dm_write_log().
> dlog() can cope with get_multipath_config() returning NULL,
> and dm_write_log() hasn't accessed the configuration for a while.
>
> Signed-off-by: Martin Wilck <mwilck at suse.com>
> ---
> multipathd/main.c | 24 ++++++++++++++----------
> 1 file changed, 14 insertions(+), 10 deletions(-)
>
> diff --git a/multipathd/main.c b/multipathd/main.c
> index 8b9df55..4d5b40b 100644
> --- a/multipathd/main.c
> +++ b/multipathd/main.c
> @@ -2892,6 +2892,16 @@ set_oom_adj (void)
> condlog(0, "couldn't adjust oom score");
> }
>
> +static void cleanup_conf(void) {
> + struct config *conf;
> +
> + conf = rcu_dereference(multipath_conf);
> + if (!conf)
> + return;
> + rcu_assign_pointer(multipath_conf, NULL);
> + call_rcu(&conf->rcu, rcu_free_config);
> +}
> +
> static void cleanup_maps(struct vectors *vecs)
> {
> int queue_without_daemon, i;
> @@ -3194,17 +3204,11 @@ child (__attribute__((unused)) void *param)
>
> condlog(2, "--------shut down-------");
>
> - if (logsink == 1)
> + if (logsink == 1) {
> + logsink = 0;
> log_thread_stop();
It seems like log_thread_stop() could just do something like
pthread_t log_thr_save = log_thr;
log_thr = (pthread_t)0;
at the start, and then you would continue to get syslog logging, even
when the log thread stopped. It's racy, but all the other threads
(except the log_thread, obviously) should be stopped. Or am I not
understanding the purpose of doing this?
> -
> - /*
> - * Freeing config must be done after condlog() and dm_lib_exit(),
> - * because logging functions like dlog() and dm_write_log()
> - * reference the config.
> - */
> - conf = rcu_dereference(multipath_conf);
> - rcu_assign_pointer(multipath_conf, NULL);
> - call_rcu(&conf->rcu, rcu_free_config);
> + }
> + cleanup_conf();
> #ifdef _DEBUG_
> dbg_free_final(NULL);
> #endif
> --
> 2.28.0
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