libiscsi: Fix host busy blocking during connection teardown (660d0831) · Commits · 戴 / test

In case of hw iscsi offload, an host can have N-number of active connections. There can be IO's running on some connections which make host->host_busy always TRUE. Now if logout from a connection is tried then the code gets into an infinite loop as host->host_busy is always TRUE. iscsi_conn_teardown(....) { ......... /* * Block until all in-progress commands for this connection * time out or fail. */ for (;;) { spin_lock_irqsave(session->host->host_lock, flags); if (!atomic_read(&session->host->host_busy)) { /* OK for ERL == 0 */ spin_unlock_irqrestore(session->host->host_lock, flags); break; } spin_unlock_irqrestore(session->host->host_lock, flags); msleep_interruptible(500); iscsi_conn_printk(KERN_INFO, conn, "iscsi conn_destroy(): " "host_busy %d host_failed %d\n", atomic_read(&session->host->host_busy), session->host->host_failed); ................ ............... } } This is not an issue with software-iscsi/iser as each cxn is a separate host. Fix: Acquiring eh_mutex in iscsi_conn_teardown() before setting session->state = ISCSI_STATE_TERMINATE. Signed-off-by:

John Soni Jose <sony.john@avagotech.com> Reviewed-by:

Mike Christie <michaelc@cs.wisc.edu> Reviewed-by:

Chris Leech <cleech@redhat.com> Cc: stable@vger.kernel.org Signed-off-by:

James Bottomley <JBottomley@Odin.com>

drivers/scsi/libiscsi.c

+2 −23

Original line number	Diff line number	Diff line
		@@ -2941,10 +2941,10 @@ void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn)
		{
		struct iscsi_conn *conn = cls_conn->dd_data;
		struct iscsi_session *session = conn->session;
		unsigned long flags;

		del_timer_sync(&conn->transport_timer);

		mutex_lock(&session->eh_mutex);
		spin_lock_bh(&session->frwd_lock);
		conn->c_stage = ISCSI_CONN_CLEANUP_WAIT;
		if (session->leadconn == conn) {
		@@ -2956,28 +2956,6 @@ void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn)
		}
		spin_unlock_bh(&session->frwd_lock);

		/*
		* Block until all in-progress commands for this connection
		* time out or fail.
		*/
		for (;;) {
		spin_lock_irqsave(session->host->host_lock, flags);
		if (!atomic_read(&session->host->host_busy)) { /* OK for ERL == 0 */
		spin_unlock_irqrestore(session->host->host_lock, flags);
		break;
		}
		spin_unlock_irqrestore(session->host->host_lock, flags);
		msleep_interruptible(500);
		iscsi_conn_printk(KERN_INFO, conn, "iscsi conn_destroy(): "
		"host_busy %d host_failed %d\n",
		atomic_read(&session->host->host_busy),
		session->host->host_failed);
		/*
		* force eh_abort() to unblock
		*/
		wake_up(&conn->ehwait);
		}

		/* flush queued up work because we free the connection below */
		iscsi_suspend_tx(conn);

		@@ -2994,6 +2972,7 @@ void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn)
		if (session->leadconn == conn)
		session->leadconn = NULL;
		spin_unlock_bh(&session->frwd_lock);
		mutex_unlock(&session->eh_mutex);

		iscsi_destroy_conn(cls_conn);
		}

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