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Commit 2ad8099b authored by Andy Grover's avatar Andy Grover
Browse files

RDS: rds_send_xmit() locking/irq fixes 



rds_message_put() cannot be called with irqs off, so move it after
irqs are re-enabled.

Spinlocks throughout the function do not to use _irqsave because
the lock of c_send_lock at top already disabled irqs.

Signed-off-by: default avatarAndy Grover <andy.grover@oracle.com>
parent 049ee3f5

net/rds/send.c

+12 −9
Original line number Diff line number Diff line
@@ -168,7 +168,7 @@ int rds_send_xmit(struct rds_connection *conn) 
		if (!rm) {

			unsigned int len;



			spin_lock_irqsave(&conn->c_lock, flags);

			spin_lock(&conn->c_lock);



			if (!list_empty(&conn->c_send_queue)) {

				rm = list_entry(conn->c_send_queue.next,
@@ -183,7 +183,7 @@ int rds_send_xmit(struct rds_connection *conn) 
				list_move_tail(&rm->m_conn_item, &conn->c_retrans);

			}



			spin_unlock_irqrestore(&conn->c_lock, flags);

			spin_unlock(&conn->c_lock);



			if (!rm) {

				was_empty = 1;
@@ -199,11 +199,10 @@ int rds_send_xmit(struct rds_connection *conn) 
			 */

			if (rm->rdma.op_active &&

			    test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) {

				spin_lock_irqsave(&conn->c_lock, flags);

				spin_lock(&conn->c_lock);

				if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags))

					list_move(&rm->m_conn_item, &to_be_dropped);

				spin_unlock_irqrestore(&conn->c_lock, flags);

				rds_message_put(rm);

				spin_unlock(&conn->c_lock);

				continue;

			}
@@ -326,10 +325,6 @@ int rds_send_xmit(struct rds_connection *conn) 
		}

	}



	/* Nuke any messages we decided not to retransmit. */

	if (!list_empty(&to_be_dropped))

		rds_send_remove_from_sock(&to_be_dropped, RDS_RDMA_DROPPED);



	if (conn->c_trans->xmit_complete)

		conn->c_trans->xmit_complete(conn);
@@ -347,6 +342,14 @@ int rds_send_xmit(struct rds_connection *conn) 
	 */

	spin_unlock_irqrestore(&conn->c_send_lock, flags);



	/* Nuke any messages we decided not to retransmit. */

	if (!list_empty(&to_be_dropped)) {

		/* irqs on here, so we can put(), unlike above */

		list_for_each_entry(rm, &to_be_dropped, m_conn_item)

			rds_message_put(rm);

		rds_send_remove_from_sock(&to_be_dropped, RDS_RDMA_DROPPED);

	}



	if (send_quota == 0 && !was_empty) {

		/* We exhausted the send quota, but there's work left to

		 * do. Return and (re-)schedule the send worker.