[PATCH v2 2/4] eal: new function to create control threads

[Olivier Matz <olivier.matz@6wind.com>]

Many parts of dpdk use their own management threads. Introduce a new
wrapper for thread creation that will be extended in next commits to set
the name and affinity.

To be consistent with other DPDK APIs, the return value is negative in
case of error, which was not the case for pthread_create().

Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
---
 drivers/net/kni/Makefile                       |  1 +
 drivers/net/kni/rte_eth_kni.c                  |  2 +-
 lib/librte_eal/common/eal_common_thread.c      |  8 ++++++++
 lib/librte_eal/common/include/rte_lcore.h      | 21 +++++++++++++++++++++
 lib/librte_eal/linuxapp/eal/eal_interrupts.c   |  6 +++---
 lib/librte_eal/linuxapp/eal/eal_timer.c        |  2 +-
 lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c |  2 +-
 lib/librte_eal/rte_eal_version.map             |  1 +
 lib/librte_pdump/Makefile                      |  1 +
 lib/librte_pdump/rte_pdump.c                   |  5 +++--
 lib/librte_vhost/socket.c                      |  6 +++---
 11 files changed, 44 insertions(+), 11 deletions(-)

diff --git a/drivers/net/kni/Makefile b/drivers/net/kni/Makefile
index 01eaef056..562e8d2da 100644
--- a/drivers/net/kni/Makefile
+++ b/drivers/net/kni/Makefile
@@ -10,6 +10,7 @@ LIB = librte_pmd_kni.a
 
 CFLAGS += -O3
 CFLAGS += $(WERROR_FLAGS)
+CFLAGS += -DALLOW_EXPERIMENTAL_API
 LDLIBS += -lpthread
 LDLIBS += -lrte_eal -lrte_mbuf -lrte_mempool -lrte_ring
 LDLIBS += -lrte_ethdev -lrte_net -lrte_kvargs -lrte_kni
diff --git a/drivers/net/kni/rte_eth_kni.c b/drivers/net/kni/rte_eth_kni.c
index dc4e65f5d..26718eb3e 100644
--- a/drivers/net/kni/rte_eth_kni.c
+++ b/drivers/net/kni/rte_eth_kni.c
@@ -149,7 +149,7 @@ eth_kni_dev_start(struct rte_eth_dev *dev)
 	}
 
 	if (internals->no_request_thread == 0) {
-		ret = pthread_create(&internals->thread, NULL,
+		ret = rte_ctrl_thread_create(&internals->thread, NULL,
 			kni_handle_request, internals);
 		if (ret) {
 			RTE_LOG(ERR, PMD,
diff --git a/lib/librte_eal/common/eal_common_thread.c b/lib/librte_eal/common/eal_common_thread.c
index 40902e49b..efbccddbc 100644
--- a/lib/librte_eal/common/eal_common_thread.c
+++ b/lib/librte_eal/common/eal_common_thread.c
@@ -140,3 +140,11 @@ eal_thread_dump_affinity(char *str, unsigned size)
 
 	return ret;
 }
+
+__rte_experimental int
+rte_ctrl_thread_create(pthread_t *thread,
+			const pthread_attr_t *attr,
+			void *(*start_routine)(void *), void *arg)
+{
+	return pthread_create(thread, attr, start_routine, arg);
+}
diff --git a/lib/librte_eal/common/include/rte_lcore.h b/lib/librte_eal/common/include/rte_lcore.h
index 047222030..f19075a88 100644
--- a/lib/librte_eal/common/include/rte_lcore.h
+++ b/lib/librte_eal/common/include/rte_lcore.h
@@ -247,6 +247,27 @@ void rte_thread_get_affinity(rte_cpuset_t *cpusetp);
 int rte_thread_setname(pthread_t id, const char *name);
 
 /**
+ * Create a control thread.
+ *
+ * Wrapper to pthread_create().
+ *
+ * @param thread
+ *   Filled with the thread id of the new created thread.
+ * @param attr
+ *   Attributes for the new thread.
+ * @param start_routine
+ *   Function to be executed by the new thread.
+ * @param arg
+ *   Argument passed to start_routine.
+ * @return
+ *   On success, returns 0; on error, it returns a negative value
+ *   corresponding to the error number.
+ */
+__rte_experimental int
+rte_ctrl_thread_create(pthread_t *thread, const pthread_attr_t *attr,
+		void *(*start_routine)(void *), void *arg);
+
+/**
  * Test if the core supplied has a specific role
  *
  * @param lcore_id
diff --git a/lib/librte_eal/linuxapp/eal/eal_interrupts.c b/lib/librte_eal/linuxapp/eal/eal_interrupts.c
index f86f22f7b..d927fb45d 100644
--- a/lib/librte_eal/linuxapp/eal/eal_interrupts.c
+++ b/lib/librte_eal/linuxapp/eal/eal_interrupts.c
@@ -860,10 +860,10 @@ rte_eal_intr_init(void)
 	}
 
 	/* create the host thread to wait/handle the interrupt */
-	ret = pthread_create(&intr_thread, NULL,
+	ret = rte_ctrl_thread_create(&intr_thread, NULL,
 			eal_intr_thread_main, NULL);
 	if (ret != 0) {
-		rte_errno = ret;
+		rte_errno = -ret;
 		RTE_LOG(ERR, EAL,
 			"Failed to create thread for interrupt handling\n");
 	} else {
@@ -876,7 +876,7 @@ rte_eal_intr_init(void)
 			"Failed to set thread name for interrupt handling\n");
 	}
 
-	return -ret;
+	return ret;
 }
 
 static void
diff --git a/lib/librte_eal/linuxapp/eal/eal_timer.c b/lib/librte_eal/linuxapp/eal/eal_timer.c
index 161322f23..f12d2e134 100644
--- a/lib/librte_eal/linuxapp/eal/eal_timer.c
+++ b/lib/librte_eal/linuxapp/eal/eal_timer.c
@@ -178,7 +178,7 @@ rte_eal_hpet_init(int make_default)
 
 	/* create a thread that will increment a global variable for
 	 * msb (hpet is 32 bits by default under linux) */
-	ret = pthread_create(&msb_inc_thread_id, NULL,
+	ret = rte_ctrl_thread_create(&msb_inc_thread_id, NULL,
 			(void *(*)(void *))hpet_msb_inc, NULL);
 	if (ret != 0) {
 		RTE_LOG(ERR, EAL, "ERROR: Cannot create HPET timer thread!\n");
diff --git a/lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c b/lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c
index 7cc3c1527..072c0a978 100644
--- a/lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c
+++ b/lib/librte_eal/linuxapp/eal/eal_vfio_mp_sync.c
@@ -374,7 +374,7 @@ vfio_mp_sync_setup(void)
 		return -1;
 	}
 
-	ret = pthread_create(&socket_thread, NULL,
+	ret = rte_ctrl_thread_create(&socket_thread, NULL,
 			vfio_mp_sync_thread, NULL);
 	if (ret) {
 		RTE_LOG(ERR, EAL,
diff --git a/lib/librte_eal/rte_eal_version.map b/lib/librte_eal/rte_eal_version.map
index f331f54c9..ef8154b60 100644
--- a/lib/librte_eal/rte_eal_version.map
+++ b/lib/librte_eal/rte_eal_version.map
@@ -214,6 +214,7 @@ DPDK_18.02 {
 EXPERIMENTAL {
 	global:
 
+	rte_ctrl_thread_create;
 	rte_eal_cleanup;
 	rte_eal_devargs_insert;
 	rte_eal_devargs_parse;
diff --git a/lib/librte_pdump/Makefile b/lib/librte_pdump/Makefile
index 98fa752ec..d72a90a60 100644
--- a/lib/librte_pdump/Makefile
+++ b/lib/librte_pdump/Makefile
@@ -6,6 +6,7 @@ include $(RTE_SDK)/mk/rte.vars.mk
 # library name
 LIB = librte_pdump.a
 
+CFLAGS += -DALLOW_EXPERIMENTAL_API
 CFLAGS += $(WERROR_FLAGS) -I$(SRCDIR) -O3
 CFLAGS += -D_GNU_SOURCE
 LDLIBS += -lpthread
diff --git a/lib/librte_pdump/rte_pdump.c b/lib/librte_pdump/rte_pdump.c
index 4fb0b4204..248912c0a 100644
--- a/lib/librte_pdump/rte_pdump.c
+++ b/lib/librte_pdump/rte_pdump.c
@@ -548,11 +548,12 @@ rte_pdump_init(const char *path)
 	}
 
 	/* create the host thread to wait/handle pdump requests */
-	ret = pthread_create(&pdump_thread, NULL, pdump_thread_main, NULL);
+	ret = rte_ctrl_thread_create(&pdump_thread, NULL,
+				pdump_thread_main, NULL);
 	if (ret != 0) {
 		RTE_LOG(ERR, PDUMP,
 			"Failed to create the pdump thread:%s, %s:%d\n",
-			strerror(ret), __func__, __LINE__);
+			strerror(-ret), __func__, __LINE__);
 		return -1;
 	}
 	/* Set thread_name for aid in debugging. */
diff --git a/lib/librte_vhost/socket.c b/lib/librte_vhost/socket.c
index a0a95f950..8112f48e7 100644
--- a/lib/librte_vhost/socket.c
+++ b/lib/librte_vhost/socket.c
@@ -467,7 +467,7 @@ vhost_user_reconnect_init(void)
 	}
 	TAILQ_INIT(&reconn_list.head);
 
-	ret = pthread_create(&reconn_tid, NULL,
+	ret = rte_ctrl_thread_create(&reconn_tid, NULL,
 			     vhost_user_client_reconnect, NULL);
 	if (ret != 0) {
 		RTE_LOG(ERR, VHOST_CONFIG, "failed to create reconnect thread");
@@ -862,8 +862,8 @@ rte_vhost_driver_start(const char *path)
 			return -1;
 		}
 
-		int ret = pthread_create(&fdset_tid, NULL, fdset_event_dispatch,
-				     &vhost_user.fdset);
+		int ret = rte_ctrl_thread_create(&fdset_tid, NULL,
+			fdset_event_dispatch, &vhost_user.fdset);
 		if (ret != 0) {
 			RTE_LOG(ERR, VHOST_CONFIG,
 				"failed to create fdset handling thread");
-- 
2.11.0