[stgt] [PATCH 06/12] Add iscsi_thread_fn to add thread per target support

[Chandra Seetharaman]

Create thread per iSCSI target.

Signed-off-by: FUJITA Tomonori <fujita.tomonori at lab.ntt.co.jp>
Signed-off-by: Chandra Seetharaman <sekharan at us.ibm.com>

---
 usr/iscsi/iscsid.h |    7 ++++++
 usr/iscsi/target.c |   66 +++++++++++++++++++++++++++++++++++++++++++++++++++--
 2 files changed, 71 insertions(+), 2 deletions(-)

 struct it_nexus {
Index: tgt-1.0.8.4/usr/iscsi/iscsid.h
===================================================================
--- tgt-1.0.8.4.orig/usr/iscsi/iscsid.h
+++ tgt-1.0.8.4/usr/iscsi/iscsid.h
@@ -251,6 +251,13 @@ struct iscsi_target {
 	} redirect_info;
 
 	struct list_head isns_list;
+
+	int efd;
+	pthread_mutex_t event_lock;
+	struct list_head events_list;
+
+	pthread_t thread;
+	int stop_pthread;
 };
 
 enum task_flags {
Index: tgt-1.0.8.4/usr/iscsi/target.c
===================================================================
--- tgt-1.0.8.4.orig/usr/iscsi/target.c
+++ tgt-1.0.8.4/usr/iscsi/target.c
@@ -25,6 +25,7 @@
 #include <unistd.h>
 #include <netdb.h>
 #include <sys/stat.h>
+#include <sys/epoll.h>
 #include <sys/un.h>
 #include <netinet/in.h>
 #include <sys/socket.h>
@@ -32,10 +33,12 @@
 #include <netinet/tcp.h>
 #include <netinet/ip.h>
 #include <arpa/inet.h>
+#include <pthread.h>
 #include "iscsid.h"
 #include "tgtadm.h"
 #include "tgtd.h"
 #include "target.h"
+#include "util.h"
 
 LIST_HEAD(iscsi_targets_list);
 
@@ -303,12 +306,53 @@ void iscsi_target_destroy(int tid)
 	}
 
 	list_del(&target->tlist);
+
+	if (target->thread) {
+		target->stop_pthread = 1;
+		pthread_kill(target->thread, SIGUSR2);
+
+		pthread_join(target->thread, NULL);
+	}
+
+	close(target->efd);
 	free(target);
 	isns_target_deregister(tgt_targetname(tid));
 
 	return;
 }
 
+static void *iscsi_thread_fn(void *arg)
+{
+	struct iscsi_target *t = arg;
+	struct epoll_event events[1024];
+	struct event_data *tev;
+	sigset_t mask;
+	int nevent, i;
+
+	sigemptyset(&mask);
+	sigaddset(&mask, SIGUSR2);
+	pthread_sigmask(SIG_BLOCK, &mask, NULL);
+
+retry:
+	nevent = epoll_wait(t->efd, events, ARRAY_SIZE(events), 1000);
+	if (nevent < 0) {
+		if (errno != EINTR) {
+			eprintf("%m\n");
+			exit(1);
+		}
+	} else if (nevent) {
+		for (i = 0; i < nevent; i++) {
+			tev = (struct event_data *) events[i].data.ptr;
+			tev->handler(tev->fd, events[i].events, tev->data);
+		}
+	}
+
+	if (!t->stop_pthread)
+		goto retry;
+
+	pthread_exit(NULL);
+}
+
 int iscsi_target_create(struct target *t)
 {
 	int tid = t->tid;
@@ -339,11 +383,15 @@ int iscsi_target_create(struct target *t
 		[ISCSI_PARAM_MAX_OUTST_PDU] =  {0, 0},  /* not in open-iscsi */
 	};
 
-	target = malloc(sizeof(*target));
+	target = zalloc(sizeof(*target));
 	if (!target)
 		return -ENOMEM;
 
-	memset(target, 0, sizeof(*target));
+	target->efd = epoll_create(128);
+	if (target->efd < 0) {
+		free(target);
+		return -EINVAL;
+	}
 
 	memcpy(target->session_param, default_tgt_session_param,
 	       sizeof(target->session_param));
@@ -351,10 +399,24 @@ int iscsi_target_create(struct target *t
 	INIT_LIST_HEAD(&target->tlist);
 	INIT_LIST_HEAD(&target->sessions_list);
 	INIT_LIST_HEAD(&target->isns_list);
+	INIT_LIST_HEAD(&target->events_list);
+	pthread_mutex_init(&target->event_lock, NULL);
 	target->tid = tid;
 	list_add_tail(&target->tlist, &iscsi_targets_list);
 
 	isns_target_register(tgt_targetname(tid));
+
+	if (iscsi_pthread_per_target()) {
+		int ret;
+
+		ret = pthread_create(&target->thread,
+					NULL, iscsi_thread_fn, target);
+
+		if (!ret)
+			eprintf("created thread %u for target %s\n",
+				(unsigned)target->thread, tgt_targetname(tid));
+	}
+
 	return 0;
 }
 
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