[dpdk-dev] [PATCH v4] eal: fix use wrong time API

[Chengwen Feng]

Currently, the mp uses gettimeofday() API to get the time, and used as
timeout parameter.

But the time which gets from gettimeofday() API isn't monotonically
increasing. The process may fail if the system time is changed.

This fixes it by using clock_gettime() API with monotonic attribution.

Fixes: 783b6e54971d ("eal: add synchronous multi-process communication")
Fixes: f05e26051c15 ("eal: add IPC asynchronous request")
Cc: stable at dpdk.org

Signed-off-by: Chengwen Feng <fengchengwen at huawei.com>
Signed-off-by: Min Hu (Connor) <humin29 at huawei.com>
Acked-by: Morten Brørup <mb at smartsharesystems.com>
---
v4:
* add check clock_gettime() API's retcode
v3:
* add acked-by.
* change patch's author.
v2:
* get rid of the CLOCK_TYPE_ID definition and use CLOCK_MONOTONIC
instead.
---
 lib/eal/common/eal_common_proc.c | 27 +++++++++++++--------------
 1 file changed, 13 insertions(+), 14 deletions(-)

diff --git a/lib/eal/common/eal_common_proc.c b/lib/eal/common/eal_common_proc.c
index 6d1af3c..dc4a2ef 100644
--- a/lib/eal/common/eal_common_proc.c
+++ b/lib/eal/common/eal_common_proc.c
@@ -490,14 +490,11 @@ async_reply_handle_thread_unsafe(void *arg)
 	struct pending_request *req = (struct pending_request *)arg;
 	enum async_action action;
 	struct timespec ts_now;
-	struct timeval now;
 
-	if (gettimeofday(&now, NULL) < 0) {
+	if (clock_gettime(CLOCK_MONOTONIC, &ts_now) < 0) {
 		RTE_LOG(ERR, EAL, "Cannot get current time\n");
 		goto no_trigger;
 	}
-	ts_now.tv_nsec = now.tv_usec * 1000;
-	ts_now.tv_sec = now.tv_sec;
 
 	action = process_async_request(req, &ts_now);
 
@@ -896,6 +893,7 @@ mp_request_sync(const char *dst, struct rte_mp_msg *req,
 	       struct rte_mp_reply *reply, const struct timespec *ts)
 {
 	int ret;
+	pthread_condattr_t attr;
 	struct rte_mp_msg msg, *tmp;
 	struct pending_request pending_req, *exist;
 
@@ -904,7 +902,9 @@ mp_request_sync(const char *dst, struct rte_mp_msg *req,
 	strlcpy(pending_req.dst, dst, sizeof(pending_req.dst));
 	pending_req.request = req;
 	pending_req.reply = &msg;
-	pthread_cond_init(&pending_req.sync.cond, NULL);
+	pthread_condattr_init(&attr);
+	pthread_condattr_setclock(&attr, CLOCK_MONOTONIC);
+	pthread_cond_init(&pending_req.sync.cond, &attr);
 
 	exist = find_pending_request(dst, req->name);
 	if (exist) {
@@ -967,8 +967,7 @@ rte_mp_request_sync(struct rte_mp_msg *req, struct rte_mp_reply *reply,
 	int dir_fd, ret = -1;
 	DIR *mp_dir;
 	struct dirent *ent;
-	struct timeval now;
-	struct timespec end;
+	struct timespec now, end;
 	const struct internal_config *internal_conf =
 		eal_get_internal_configuration();
 
@@ -987,15 +986,15 @@ rte_mp_request_sync(struct rte_mp_msg *req, struct rte_mp_reply *reply,
 		return -1;
 	}
 
-	if (gettimeofday(&now, NULL) < 0) {
+	if (clock_gettime(CLOCK_MONOTONIC, &now) < 0) {
 		RTE_LOG(ERR, EAL, "Failed to get current time\n");
 		rte_errno = errno;
 		goto end;
 	}
 
-	end.tv_nsec = (now.tv_usec * 1000 + ts->tv_nsec) % 1000000000;
+	end.tv_nsec = (now.tv_nsec + ts->tv_nsec) % 1000000000;
 	end.tv_sec = now.tv_sec + ts->tv_sec +
-			(now.tv_usec * 1000 + ts->tv_nsec) / 1000000000;
+			(now.tv_nsec + ts->tv_nsec) / 1000000000;
 
 	/* for secondary process, send request to the primary process only */
 	if (rte_eal_process_type() == RTE_PROC_SECONDARY) {
@@ -1069,7 +1068,7 @@ rte_mp_request_async(struct rte_mp_msg *req, const struct timespec *ts,
 	int dir_fd, ret = 0;
 	DIR *mp_dir;
 	struct dirent *ent;
-	struct timeval now;
+	struct timespec now;
 	struct timespec *end;
 	bool dummy_used = false;
 	const struct internal_config *internal_conf =
@@ -1086,7 +1085,7 @@ rte_mp_request_async(struct rte_mp_msg *req, const struct timespec *ts,
 		return -1;
 	}
 
-	if (gettimeofday(&now, NULL) < 0) {
+	if (clock_gettime(CLOCK_MONOTONIC, &now) < 0) {
 		RTE_LOG(ERR, EAL, "Failed to get current time\n");
 		rte_errno = errno;
 		return -1;
@@ -1108,9 +1107,9 @@ rte_mp_request_async(struct rte_mp_msg *req, const struct timespec *ts,
 	end = &param->end;
 	reply = &param->user_reply;
 
-	end->tv_nsec = (now.tv_usec * 1000 + ts->tv_nsec) % 1000000000;
+	end->tv_nsec = (now.tv_nsec + ts->tv_nsec) % 1000000000;
 	end->tv_sec = now.tv_sec + ts->tv_sec +
-			(now.tv_usec * 1000 + ts->tv_nsec) / 1000000000;
+			(now.tv_nsec + ts->tv_nsec) / 1000000000;
 	reply->nb_sent = 0;
 	reply->nb_received = 0;
 	reply->msgs = NULL;
-- 
2.8.1