[PATCH v5 01/11] drivers: PL011: avoid potential unregister_driver call
From: Andre Przywara <andre.przywara@arm.com>
Date: 2015-05-21 16:26:14
Also in:
linux-arm-kernel
Subsystem:
arm primecell uart pl010 and pl011 drivers, the rest, tty layer and serial drivers · Maintainers:
Russell King, Linus Torvalds, Greg Kroah-Hartman, Jiri Slaby
Although we care about not unregistering the driver if there are still ports connected during the .remove callback, we do miss this check in the pl011_probe function. So if the current port allocation fails, but there are other ports already registered, we will kill those. So factor out the port removal into a separate function and use that in the probe function, too. Signed-off-by: Andre Przywara <andre.przywara@arm.com> --- drivers/tty/serial/amba-pl011.c | 36 ++++++++++++++++++++---------------- 1 file changed, 20 insertions(+), 16 deletions(-)
diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c
index f5bd842..b4de23c 100644
--- a/drivers/tty/serial/amba-pl011.c
+++ b/drivers/tty/serial/amba-pl011.c@@ -2135,6 +2135,23 @@ static int pl011_probe_dt_alias(int index, struct device *dev) return ret; } +/* unregisters the driver also if no more ports are left */ +static void pl011_unregister_port(struct uart_amba_port *uap) +{ + int i; + bool busy = false; + + for (i = 0; i < ARRAY_SIZE(amba_ports); i++) { + if (amba_ports[i] == uap) + amba_ports[i] = NULL; + else if (amba_ports[i]) + busy = true; + } + pl011_dma_remove(uap); + if (!busy) + uart_unregister_driver(&amba_reg); +} + static int pl011_probe(struct amba_device *dev, const struct amba_id *id) { struct uart_amba_port *uap;
@@ -2200,10 +2217,8 @@ static int pl011_probe(struct amba_device *dev, const struct amba_id *id) } ret = uart_add_one_port(&amba_reg, &uap->port); - if (ret) { - amba_ports[i] = NULL; - uart_unregister_driver(&amba_reg); - } + if (ret) + pl011_unregister_port(uap); return ret; }
@@ -2211,20 +2226,9 @@ static int pl011_probe(struct amba_device *dev, const struct amba_id *id) static int pl011_remove(struct amba_device *dev) { struct uart_amba_port *uap = amba_get_drvdata(dev); - bool busy = false; - int i; uart_remove_one_port(&amba_reg, &uap->port); - - for (i = 0; i < ARRAY_SIZE(amba_ports); i++) - if (amba_ports[i] == uap) - amba_ports[i] = NULL; - else if (amba_ports[i]) - busy = true; - - pl011_dma_remove(uap); - if (!busy) - uart_unregister_driver(&amba_reg); + pl011_unregister_port(uap); return 0; }
--
2.3.5