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Message-ID: <20241211074933.92973-2-jirislaby@kernel.org>
Date: Wed, 11 Dec 2024 08:49:31 +0100
From: "Jiri Slaby (SUSE)" <jirislaby@...nel.org>
To: gregkh@...uxfoundation.org
Cc: linux-serial@...r.kernel.org,
linux-kernel@...r.kernel.org,
"Jiri Slaby (SUSE)" <jirislaby@...nel.org>
Subject: [PATCH 1/3] tty: serial_core: use more guard(mutex)
Simplify 4 more functions using guard(mutex): uart_get_info(),
console_store(), serial_core_add_one_port(), and
serial_core_register_port(). Especially console_store() is now much less
convoluted. In the others, we save some goto-s and even local variables
are dropped in some.
Signed-off-by: Jiri Slaby (SUSE) <jirislaby@...nel.org>
---
drivers/tty/serial/serial_core.c | 83 ++++++++++++--------------------
1 file changed, 31 insertions(+), 52 deletions(-)
diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c
index 74fa02b23772..f595f2336fc0 100644
--- a/drivers/tty/serial/serial_core.c
+++ b/drivers/tty/serial/serial_core.c
@@ -790,7 +790,6 @@ static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)
{
struct uart_state *state = container_of(port, struct uart_state, port);
struct uart_port *uport;
- int ret = -ENODEV;
/* Initialize structure in case we error out later to prevent any stack info leakage. */
*retinfo = (struct serial_struct){};
@@ -799,10 +798,10 @@ static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)
* Ensure the state we copy is consistent and no hardware changes
* occur as we go
*/
- mutex_lock(&port->mutex);
+ guard(mutex)(&port->mutex);
uport = uart_port_check(state);
if (!uport)
- goto out;
+ return -ENODEV;
retinfo->type = uport->type;
retinfo->line = uport->line;
@@ -823,10 +822,7 @@ static int uart_get_info(struct tty_port *port, struct serial_struct *retinfo)
retinfo->iomem_reg_shift = uport->regshift;
retinfo->iomem_base = (void *)(unsigned long)uport->mapbase;
- ret = 0;
-out:
- mutex_unlock(&port->mutex);
- return ret;
+ return 0;
}
static int uart_get_info_user(struct tty_struct *tty,
@@ -3061,26 +3057,25 @@ static ssize_t console_store(struct device *dev,
if (ret)
return ret;
- mutex_lock(&port->mutex);
+ guard(mutex)(&port->mutex);
uport = uart_port_check(state);
- if (uport) {
- oldconsole = uart_console_registered(uport);
- if (oldconsole && !newconsole) {
- ret = unregister_console(uport->cons);
- } else if (!oldconsole && newconsole) {
- if (uart_console(uport)) {
- uport->console_reinit = 1;
- register_console(uport->cons);
- } else {
- ret = -ENOENT;
- }
- }
- } else {
- ret = -ENXIO;
+ if (!uport)
+ return -ENXIO;
+
+ oldconsole = uart_console_registered(uport);
+ if (oldconsole && !newconsole) {
+ ret = unregister_console(uport->cons);
+ if (ret < 0)
+ return ret;
+ } else if (!oldconsole && newconsole) {
+ if (!uart_console(uport))
+ return -ENOENT;
+
+ uport->console_reinit = 1;
+ register_console(uport->cons);
}
- mutex_unlock(&port->mutex);
- return ret < 0 ? ret : count;
+ return count;
}
static DEVICE_ATTR_RO(uartclk);
@@ -3136,7 +3131,6 @@ static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *u
{
struct uart_state *state;
struct tty_port *port;
- int ret = 0;
struct device *tty_dev;
int num_groups;
@@ -3146,11 +3140,9 @@ static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *u
state = drv->state + uport->line;
port = &state->port;
- mutex_lock(&port->mutex);
- if (state->uart_port) {
- ret = -EINVAL;
- goto out;
- }
+ guard(mutex)(&port->mutex);
+ if (state->uart_port)
+ return -EINVAL;
/* Link the port to the driver state table and vice versa */
atomic_set(&state->refcount, 1);
@@ -3170,10 +3162,8 @@ static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *u
uport->minor = drv->tty_driver->minor_start + uport->line;
uport->name = kasprintf(GFP_KERNEL, "%s%d", drv->dev_name,
drv->tty_driver->name_base + uport->line);
- if (!uport->name) {
- ret = -ENOMEM;
- goto out;
- }
+ if (!uport->name)
+ return -ENOMEM;
if (uport->cons && uport->dev)
of_console_check(uport->dev->of_node, uport->cons->name, uport->line);
@@ -3189,10 +3179,9 @@ static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *u
uport->tty_groups = kcalloc(num_groups, sizeof(*uport->tty_groups),
GFP_KERNEL);
- if (!uport->tty_groups) {
- ret = -ENOMEM;
- goto out;
- }
+ if (!uport->tty_groups)
+ return -ENOMEM;
+
uport->tty_groups[0] = &tty_dev_attr_group;
if (uport->attr_group)
uport->tty_groups[1] = uport->attr_group;
@@ -3215,10 +3204,7 @@ static int serial_core_add_one_port(struct uart_driver *drv, struct uart_port *u
uport->line);
}
- out:
- mutex_unlock(&port->mutex);
-
- return ret;
+ return 0;
}
/**
@@ -3384,7 +3370,7 @@ int serial_core_register_port(struct uart_driver *drv, struct uart_port *port)
struct serial_ctrl_device *ctrl_dev, *new_ctrl_dev = NULL;
int ret;
- mutex_lock(&port_mutex);
+ guard(mutex)(&port_mutex);
/*
* Prevent serial_port_runtime_resume() from trying to use the port
@@ -3396,10 +3382,8 @@ int serial_core_register_port(struct uart_driver *drv, struct uart_port *port)
ctrl_dev = serial_core_ctrl_find(drv, port->dev, port->ctrl_id);
if (!ctrl_dev) {
new_ctrl_dev = serial_core_ctrl_device_add(port);
- if (IS_ERR(new_ctrl_dev)) {
- ret = PTR_ERR(new_ctrl_dev);
- goto err_unlock;
- }
+ if (IS_ERR(new_ctrl_dev))
+ return PTR_ERR(new_ctrl_dev);
ctrl_dev = new_ctrl_dev;
}
@@ -3420,8 +3404,6 @@ int serial_core_register_port(struct uart_driver *drv, struct uart_port *port)
if (ret)
goto err_unregister_port_dev;
- mutex_unlock(&port_mutex);
-
return 0;
err_unregister_port_dev:
@@ -3430,9 +3412,6 @@ int serial_core_register_port(struct uart_driver *drv, struct uart_port *port)
err_unregister_ctrl_dev:
serial_base_ctrl_device_remove(new_ctrl_dev);
-err_unlock:
- mutex_unlock(&port_mutex);
-
return ret;
}
--
2.47.1
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