From mboxrd@z Thu Jan 1 00:00:00 1970 From: andre.przywara@arm.com (Andre Przywara) Date: Wed, 4 Mar 2015 17:59:45 +0000 Subject: [PATCH v2 01/10] drivers: PL011: avoid potential unregister_driver call In-Reply-To: <1425491994-23913-1-git-send-email-andre.przywara@arm.com> References: <1425491994-23913-1-git-send-email-andre.przywara@arm.com> Message-ID: <1425491994-23913-2-git-send-email-andre.przywara@arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 --- drivers/tty/serial/amba-pl011.c | 38 +++++++++++++++++++++----------------- 1 file changed, 21 insertions(+), 17 deletions(-) diff --git a/drivers/tty/serial/amba-pl011.c b/drivers/tty/serial/amba-pl011.c index 92783fc..961f9b0 100644 --- a/drivers/tty/serial/amba-pl011.c +++ b/drivers/tty/serial/amba-pl011.c @@ -2235,6 +2235,24 @@ 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; @@ -2301,11 +2319,8 @@ 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); - pl011_dma_remove(uap); - } + if (ret) + pl011_unregister_port(uap); return ret; } @@ -2313,20 +2328,9 @@ 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; } -- 1.7.9.5