iscsi-target: Add thread_set->ts_activate_sem + use common deallocate

This patch removes the iscsi_thread_set->[rx,tx]_post_start_comp that
was originally used synchronize startup between rx and tx threads within
a single thread_set.

Instead, use a single ->ts_activate_sem in iscsi_activate_thread_set()
to wait for both processes to awake in the RX/TX pre handlers.

Also, go ahead and refactor thread_set deallocate code into a common
iscsi_deallocate_thread_one(), and update iscsi_deallocate_thread_sets()
and iscsi_deallocate_extra_thread_sets() use this code

v3 changes:
  - Make iscsi_deallocate_thread_one defined as static (Fengguang)

v2 changes:
  - Set ISCSI_THREAD_SET_ACTIVE before calling complete in
    iscsi_activate_thread_set
  - Protect ts->conn sanity checks with ->ts_state_lock in
    RX/TX pre handlers
  - Add ->ts_activate_sem to save extra context switches per
    iscsi_activate_thread_set() call.
  - Refactor thread_set shutdown into iscsi_deallocate_thread_one()

Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 1 insertions, 4 deletions

diff --git a/drivers/target/iscsi/iscsi_target_tq.h b/drivers/target/iscsi/iscsi_target_tq.h
index 547d1183128..cc1eede5ab3 100644
--- a/drivers/target/iscsi/iscsi_target_tq.h
+++ b/drivers/target/iscsi/iscsi_target_tq.h
@@ -64,10 +64,6 @@ struct iscsi_thread_set {
 	struct iscsi_conn	*conn;
 	/* used for controlling ts state accesses */
 	spinlock_t	ts_state_lock;
-	/* Used for rx side post startup */
-	struct completion	rx_post_start_comp;
-	/* Used for tx side post startup */
-	struct completion	tx_post_start_comp;
 	/* used for restarting thread queue */
 	struct completion	rx_restart_comp;
 	/* used for restarting thread queue */
@@ -82,6 +78,7 @@ struct iscsi_thread_set {
 	struct task_struct	*tx_thread;
 	/* struct iscsi_thread_set in list list head*/
 	struct list_head	ts_list;
+	struct semaphore	ts_activate_sem;
 };
 
 #endif   /*** ISCSI_THREAD_QUEUE_H ***/