Commit 5ab41ca4 authored by Nicholas Bellinger's avatar Nicholas Bellinger
Browse files

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: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent d5705c4a

drivers/target/iscsi/iscsi_target_tq.c

+58 −81
Original line number Diff line number Diff line
@@ -105,12 +105,11 @@ int iscsi_allocate_thread_sets(u32 thread_pair_count) 
		ts->status = ISCSI_THREAD_SET_FREE;

		INIT_LIST_HEAD(&ts->ts_list);

		spin_lock_init(&ts->ts_state_lock);

		init_completion(&ts->rx_post_start_comp);

		init_completion(&ts->tx_post_start_comp);

		init_completion(&ts->rx_restart_comp);

		init_completion(&ts->tx_restart_comp);

		init_completion(&ts->rx_start_comp);

		init_completion(&ts->tx_start_comp);

		sema_init(&ts->ts_activate_sem, 0);



		ts->create_threads = 1;

		ts->tx_thread = kthread_run(iscsi_target_tx_thread, ts, "%s",
@@ -139,25 +138,24 @@ int iscsi_allocate_thread_sets(u32 thread_pair_count) 
	return allocated_thread_pair_count;

}



void iscsi_deallocate_thread_sets(void)

static void iscsi_deallocate_thread_one(struct iscsi_thread_set *ts)

{

	u32 released_count = 0;

	struct iscsi_thread_set *ts = NULL;



	while ((ts = iscsi_get_ts_from_inactive_list())) {



	spin_lock_bh(&ts->ts_state_lock);

	ts->status = ISCSI_THREAD_SET_DIE;

		spin_unlock_bh(&ts->ts_state_lock);



	if (ts->rx_thread) {

			send_sig(SIGINT, ts->rx_thread, 1);

		complete(&ts->rx_start_comp);

		spin_unlock_bh(&ts->ts_state_lock);

		kthread_stop(ts->rx_thread);

		spin_lock_bh(&ts->ts_state_lock);

	}

	if (ts->tx_thread) {

			send_sig(SIGINT, ts->tx_thread, 1);

		complete(&ts->tx_start_comp);

		spin_unlock_bh(&ts->ts_state_lock);

		kthread_stop(ts->tx_thread);

		spin_lock_bh(&ts->ts_state_lock);

	}

	spin_unlock_bh(&ts->ts_state_lock);

	/*

	 * Release this thread_id in the thread_set_bitmap

	 */
@@ -166,10 +164,20 @@ void iscsi_deallocate_thread_sets(void) 
			ts->thread_id, get_order(1));

	spin_unlock(&ts_bitmap_lock);



		released_count++;

	kfree(ts);

}



void iscsi_deallocate_thread_sets(void)

{

	struct iscsi_thread_set *ts = NULL;

	u32 released_count = 0;



	while ((ts = iscsi_get_ts_from_inactive_list())) {



		iscsi_deallocate_thread_one(ts);

		released_count++;

	}



	if (released_count)

		pr_debug("Stopped %d thread set(s) (%d total threads)."

			"\n", released_count, released_count * 2);
@@ -187,39 +195,14 @@ static void iscsi_deallocate_extra_thread_sets(void) 
		if (!ts)

			break;



		spin_lock_bh(&ts->ts_state_lock);

		ts->status = ISCSI_THREAD_SET_DIE;



		if (ts->rx_thread) {

			complete(&ts->rx_start_comp);

			spin_unlock_bh(&ts->ts_state_lock);

			kthread_stop(ts->rx_thread);

			spin_lock_bh(&ts->ts_state_lock);

		}

		if (ts->tx_thread) {

			complete(&ts->tx_start_comp);

			spin_unlock_bh(&ts->ts_state_lock);

			kthread_stop(ts->tx_thread);

			spin_lock_bh(&ts->ts_state_lock);

		}

		spin_unlock_bh(&ts->ts_state_lock);

		/*

		 * Release this thread_id in the thread_set_bitmap

		 */

		spin_lock(&ts_bitmap_lock);

		bitmap_release_region(iscsit_global->ts_bitmap,

				ts->thread_id, get_order(1));

		spin_unlock(&ts_bitmap_lock);



		iscsi_deallocate_thread_one(ts);

		released_count++;

		kfree(ts);

	}



	if (released_count) {

	if (released_count)

		pr_debug("Stopped %d thread set(s) (%d total threads)."

			"\n", released_count, released_count * 2);

}

}



void iscsi_activate_thread_set(struct iscsi_conn *conn, struct iscsi_thread_set *ts)

{
@@ -228,14 +211,13 @@ void iscsi_activate_thread_set(struct iscsi_conn *conn, struct iscsi_thread_set 
	spin_lock_bh(&ts->ts_state_lock);

	conn->thread_set = ts;

	ts->conn = conn;

	ts->status = ISCSI_THREAD_SET_ACTIVE;

	spin_unlock_bh(&ts->ts_state_lock);

	/*

	 * Start up the RX thread and wait on rx_post_start_comp.  The RX

	 * Thread will then do the same for the TX Thread in

	 * iscsi_rx_thread_pre_handler().

	 */



	complete(&ts->rx_start_comp);

	wait_for_completion(&ts->rx_post_start_comp);

	complete(&ts->tx_start_comp);



	down(&ts->ts_activate_sem);

}



struct iscsi_thread_set *iscsi_get_thread_set(void)
@@ -267,6 +249,7 @@ get_set: 
	ts->thread_count = 2;

	init_completion(&ts->rx_restart_comp);

	init_completion(&ts->tx_restart_comp);

	sema_init(&ts->ts_activate_sem, 0);



	return ts;

}
@@ -452,18 +435,19 @@ sleep: 
	if (iscsi_signal_thread_pre_handler(ts) < 0)

		return NULL;



	iscsi_check_to_add_additional_sets();



	spin_lock_bh(&ts->ts_state_lock);

	if (!ts->conn) {

		pr_err("struct iscsi_thread_set->conn is NULL for"

			" thread_id: %d, going back to sleep\n", ts->thread_id);

		goto sleep;

			" RX thread_id: %s/%d\n", current->comm, current->pid);

		spin_unlock_bh(&ts->ts_state_lock);

		return NULL;

	}

	iscsi_check_to_add_additional_sets();

	/*

	 * The RX Thread starts up the TX Thread and sleeps.

	 */

	ts->thread_clear |= ISCSI_CLEAR_RX_THREAD;

	complete(&ts->tx_start_comp);

	wait_for_completion(&ts->tx_post_start_comp);

	spin_unlock_bh(&ts->ts_state_lock);



	up(&ts->ts_activate_sem);



	return ts->conn;

}
@@ -505,27 +489,20 @@ sleep: 
	if (iscsi_signal_thread_pre_handler(ts) < 0)

		return NULL;



	iscsi_check_to_add_additional_sets();



	spin_lock_bh(&ts->ts_state_lock);

	if (!ts->conn) {

		pr_err("struct iscsi_thread_set->conn is NULL for"

			" thread_id: %d, going back to sleep\n",

			ts->thread_id);

		goto sleep;

			" TX thread_id: %s/%d\n", current->comm, current->pid);

		spin_unlock_bh(&ts->ts_state_lock);

		return NULL;

	}



	iscsi_check_to_add_additional_sets();

	/*

	 * From the TX thread, up the tx_post_start_comp that the RX Thread is

	 * sleeping on in iscsi_rx_thread_pre_handler(), then up the

	 * rx_post_start_comp that iscsi_activate_thread_set() is sleeping on.

	 */

	ts->thread_clear |= ISCSI_CLEAR_TX_THREAD;

	complete(&ts->tx_post_start_comp);

	complete(&ts->rx_post_start_comp);



	spin_lock_bh(&ts->ts_state_lock);

	ts->status = ISCSI_THREAD_SET_ACTIVE;

	spin_unlock_bh(&ts->ts_state_lock);



	up(&ts->ts_activate_sem);



	return ts->conn;

}

drivers/target/iscsi/iscsi_target_tq.h

+1 −4
Original line number Diff line number Diff line
@@ -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 ***/

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