From: mwilck@suse.com
To: Christophe Varoqui <christophe.varoqui@opensvc.com>,
Benjamin Marzinski <bmarzins@redhat.com>
Cc: dm-devel@redhat.com, Martin Wilck <mwilck@suse.com>
Subject: [PATCH v2 06/21] multipathd: generalize and fix wait_for_state_change_if()
Date: Thu, 24 Sep 2020 15:37:01 +0200 [thread overview]
Message-ID: <20200924133716.14120-7-mwilck@suse.com> (raw)
In-Reply-To: <20200924133716.14120-1-mwilck@suse.com>
From: Martin Wilck <mwilck@suse.com>
It's unlikely but not impossible that other threads change the state
while we're waiting, and if we grab the lock again, it's still not
what we wanted. We need to continue waiting until either the condition
is met, or time timeout expired.
Moreover, generalize this code so that it can also be used in
set_config_state().
Reviewed-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Martin Wilck <mwilck@suse.com>
---
multipathd/main.c | 25 ++++++++++++++++++-------
1 file changed, 18 insertions(+), 7 deletions(-)
diff --git a/multipathd/main.c b/multipathd/main.c
index d081b3e..1fb0ee6 100644
--- a/multipathd/main.c
+++ b/multipathd/main.c
@@ -223,6 +223,23 @@ static void config_cleanup(__attribute__((unused)) void *arg)
pthread_mutex_unlock(&config_lock);
}
+#define __wait_for_state_change(condition, ms) \
+ ({ \
+ struct timespec tmo; \
+ int rc = 0; \
+ \
+ if (condition) { \
+ get_monotonic_time(&tmo); \
+ tmo.tv_nsec += (ms) * 1000 * 1000; \
+ normalize_timespec(&tmo); \
+ do \
+ rc = pthread_cond_timedwait( \
+ &config_cond, &config_lock, &tmo); \
+ while (rc == 0 && (condition)); \
+ } \
+ rc; \
+ })
+
/*
* If the current status is @oldstate, wait for at most @ms milliseconds
* for the state to change, and return the new state, which may still be
@@ -232,20 +249,14 @@ enum daemon_status wait_for_state_change_if(enum daemon_status oldstate,
unsigned long ms)
{
enum daemon_status st;
- struct timespec tmo;
if (oldstate == DAEMON_SHUTDOWN)
return DAEMON_SHUTDOWN;
pthread_mutex_lock(&config_lock);
pthread_cleanup_push(config_cleanup, NULL);
+ __wait_for_state_change(running_state == oldstate, ms);
st = running_state;
- if (st == oldstate && clock_gettime(CLOCK_MONOTONIC, &tmo) == 0) {
- tmo.tv_nsec += ms * 1000 * 1000;
- normalize_timespec(&tmo);
- (void)pthread_cond_timedwait(&config_cond, &config_lock, &tmo);
- st = running_state;
- }
pthread_cleanup_pop(1);
return st;
}
--
2.28.0
next prev parent reply other threads:[~2020-09-24 13:37 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-24 13:36 [PATCH v2 00/21] multipath-tools: shutdown, libdevmapper races, globals mwilck
2020-09-24 13:36 ` [PATCH v2 01/21] multipathd: allow shutdown during configure() mwilck
2020-09-24 13:36 ` [PATCH v2 02/21] multipathd: avoid sending "READY=1" to systemd on early shutdown mwilck
2020-09-24 13:36 ` [PATCH v2 03/21] multipathd: send "STOPPING=1" to systemd on shutdown mwilck
2020-09-24 13:36 ` [PATCH v2 04/21] multipathd: send "RELOADING=1" to systemd on DAEMON_CONFIGURE state mwilck
2020-09-24 13:37 ` [PATCH v2 05/21] multipathd: use volatile qualifier for running_state mwilck
2020-09-24 13:37 ` mwilck [this message]
2020-09-24 13:37 ` [PATCH v2 07/21] multipathd: set_config_state(): avoid code duplication mwilck
2020-09-24 13:37 ` [PATCH v2 08/21] multipathd: cancel threads early during shutdown mwilck
2020-09-24 13:37 ` [PATCH v2 09/21] multipath-tools: don't call dm_lib_release() any more mwilck
2020-09-24 13:37 ` [PATCH v2 10/21] libmultipath: devmapper: refactor libdm version determination mwilck
2020-09-25 23:48 ` Benjamin Marzinski
2020-09-24 13:37 ` [PATCH v2 11/21] libmultipath: protect racy libdevmapper calls with a mutex mwilck
2020-09-29 5:57 ` Benjamin Marzinski
2020-09-29 9:09 ` Martin Wilck
2020-09-24 13:37 ` [PATCH v2 12/21] libmultipath: constify file argument in config parser mwilck
2020-09-24 13:37 ` [PATCH v2 13/21] libmultipath: provide defaults for {get, put}_multipath_config mwilck
2020-09-25 4:34 ` Benjamin Marzinski
2020-09-25 20:00 ` Martin Wilck
2020-09-25 21:57 ` Benjamin Marzinski
2020-09-26 9:43 ` Martin Wilck
2020-09-27 1:03 ` Benjamin Marzinski
2020-09-24 13:37 ` [PATCH v2 14/21] libmpathpersist: allow using libmultipath " mwilck
2020-09-24 13:37 ` [PATCH v2 15/21] multipath: use {get_put}_multipath_config from libmultipath mwilck
2020-09-24 13:37 ` [PATCH v2 16/21] mpathpersist: use {get, put}_multipath_config() " mwilck
2020-09-24 13:37 ` [PATCH v2 17/21] libmultipath: add udev and logsink symbols mwilck
2020-09-25 23:03 ` Benjamin Marzinski
2020-09-25 23:05 ` Martin Wilck
2020-09-24 13:37 ` [PATCH v2 18/21] multipath: remove logsink and udev mwilck
2020-09-24 13:37 ` [PATCH v2 19/21] libmpathpersist: call libmultipath_{init, exit}() mwilck
2020-09-25 23:55 ` Benjamin Marzinski
2020-09-24 13:37 ` [PATCH v2 20/21] mpathpersist: remove logsink and udev mwilck
2020-09-25 23:56 ` Benjamin Marzinski
2020-09-24 13:37 ` [PATCH v2 21/21] multipathd: " mwilck
2020-09-26 0:19 ` Benjamin Marzinski
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