[stgt] [PATCH] iscsi: target->events_list race

[FUJITA Tomonori]

Ok, we need this for pthread per target.

=
From: FUJITA Tomonori <fujita.tomonori at lab.ntt.co.jp>
Subject: [PATCH] iscsi: target->events_list race

target->events_list can be accessed by the main and target pthreads.

Signed-off-by: FUJITA Tomonori <fujita.tomonori at lab.ntt.co.jp>
---
 usr/iscsi/iscsi_tcp.c |   11 +++++++++++
 usr/iscsi/iscsid.h    |    1 +
 usr/iscsi/target.c    |    6 ++++++
 3 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/usr/iscsi/iscsi_tcp.c b/usr/iscsi/iscsi_tcp.c
index 471eea0..d1edd84 100644
--- a/usr/iscsi/iscsi_tcp.c
+++ b/usr/iscsi/iscsi_tcp.c
@@ -31,6 +31,7 @@
 #include <netinet/tcp.h>
 #include <sys/epoll.h>
 #include <sys/socket.h>
+#include <pthread.h>
 
 #include "iscsid.h"
 #include "tgtd.h"
@@ -170,8 +171,10 @@ static void iscsi_tcp_event_handler(int fd, int events, void *data)
 		if (tcp_conn->pthread) {
 			struct iscsi_target *target = conn->session->target;
 
+			pthread_mutex_lock(&target->event_lock);
 			do_tgt_event_del(target->efd, &target->events_list,
 					 tcp_conn->fd);
+			pthread_mutex_unlock(&target->event_lock);
 			/* let the main thread handle this */
 			tcp_conn->pthread = 0;
 			tgt_event_modify(tcp_conn->fd, EPOLLIN|EPOLLOUT|EPOLLERR);
@@ -283,9 +286,15 @@ static void iscsi_tcp_conn_nexus_init(struct iscsi_connection *conn)
 	if (iscsi_pthread_per_target()) {
 		/* remove the conn from the main thread. */
 		conn->tp->ep_event_modify(conn, 0);
+
+		pthread_mutex_lock(&target->event_lock);
+
 		do_tgt_event_add(target->efd, &target->events_list,
 				 tcp_conn->fd, EPOLLIN,
 				 iscsi_tcp_event_handler, conn);
+
+		pthread_mutex_unlock(&target->event_lock);
+
 		tcp_conn->pthread = 1;
 	}
 
@@ -368,8 +377,10 @@ static void iscsi_event_modify(struct iscsi_connection *conn, int events)
 	if (tcp_conn->pthread) {
 		struct iscsi_target *target = conn->session->target;
 
+		pthread_mutex_lock(&target->event_lock);
 		do_tgt_event_modify(target->efd, &target->events_list,
 				    tcp_conn->fd, events);
+		pthread_mutex_unlock(&target->event_lock);
 	} else {
 		ret = tgt_event_modify(tcp_conn->fd, events);
 		if (ret)
diff --git a/usr/iscsi/iscsid.h b/usr/iscsi/iscsid.h
index 40f3ff4..1e70d81 100644
--- a/usr/iscsi/iscsid.h
+++ b/usr/iscsi/iscsid.h
@@ -246,6 +246,7 @@ struct iscsi_target {
 	struct list_head isns_list;
 
 	int efd;
+	pthread_mutex_t event_lock;
 	struct list_head events_list;
 
 	struct bs_finish bsfin;
diff --git a/usr/iscsi/target.c b/usr/iscsi/target.c
index cd45fb0..b547626 100644
--- a/usr/iscsi/target.c
+++ b/usr/iscsi/target.c
@@ -256,6 +256,8 @@ void iscsi_target_destroy(int tid)
 
 	list_del(&target->tlist);
 
+	pthread_mutex_init(&target->event_lock, NULL);
+
 	if (target->bsfin.thread) {
 		target->stop_pthread = 1;
 		pthread_kill(target->bsfin.thread, SIGUSR2);
@@ -283,9 +285,13 @@ static void *iscsi_thread_fn(void *arg)
 	sigaddset(&mask, SIGUSR2);
 	pthread_sigmask(SIG_BLOCK, &mask, NULL);
 
+	pthread_mutex_lock(&t->event_lock);
+
 	do_tgt_event_add(t->efd, &t->events_list, sig_fd, EPOLLIN,
 			 bs_sig_request_done, &t->bsfin);
 
+	pthread_mutex_unlock(&t->event_lock);
+
 retry:
 	nevent = epoll_wait(t->efd, events, ARRAY_SIZE(events), 1000);
 	if (nevent < 0) {
-- 
1.6.5

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