ata: sata_mv: Cleanup only the initialized ports

When an error occurs in the port initialization loop, currently the
driver tries to cleanup all the ports. This results in a NULL pointer
dereference if the ports were only partially initialized.

Fix this by updating only the number of initialized ports (either
with failure or successfully), before jumping to the error path
and looping over that number in the cleanup loop.

Cc: Andrew Lunn <andrew@lunn.ch>
Reported-by: Mikael Pettersson <mikpelinux@gmail.com>
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: stable@vger.kernel.org

drivers/ata/sata_mv.c

@@ -4104,7 +4104,6 @@ static int mv_platform_probe(struct platform_device *pdev)
 	if (!hpriv->port_phys)
 		return -ENOMEM;
 	host->private_data = hpriv;
-	hpriv->n_ports = n_ports;
 	hpriv->board_idx = chip_soc;
 
 	host->iomap = NULL;
@@ -4132,11 +4131,17 @@ static int mv_platform_probe(struct platform_device *pdev)
 			hpriv->port_phys[port] = NULL;
 			if ((rc != -EPROBE_DEFER) && (rc != -ENODEV))
 				dev_warn(&pdev->dev, "error getting phy");
+
+			/* Cleanup only the initialized ports */
+			hpriv->n_ports = port;
 			goto err;
 		} else
 			phy_power_on(hpriv->port_phys[port]);
 	}
 
+	/* All the ports have been initialized */
+	hpriv->n_ports = n_ports;
+
 	/*
 	 * (Re-)program MBUS remapping windows if we are asked to.
 	 */
@@ -4174,7 +4179,7 @@ static int mv_platform_probe(struct platform_device *pdev)
 		clk_disable_unprepare(hpriv->clk);
 		clk_put(hpriv->clk);
 	}
-	for (port = 0; port < n_ports; port++) {
+	for (port = 0; port < hpriv->n_ports; port++) {
 		if (!IS_ERR(hpriv->port_clks[port])) {
 			clk_disable_unprepare(hpriv->port_clks[port]);
 			clk_put(hpriv->port_clks[port]);