diff options
| -rw-r--r-- | drivers/serial/serial_core.c | 114 | ||||
| -rw-r--r-- | include/linux/serial_core.h | 1 |
2 files changed, 61 insertions, 54 deletions
diff --git a/drivers/serial/serial_core.c b/drivers/serial/serial_core.c index fcd7744..aeb8153 100644 --- a/drivers/serial/serial_core.c +++ b/drivers/serial/serial_core.c @@ -1500,20 +1500,18 @@ uart_block_til_ready(struct file *filp, struct uart_state *state) static struct uart_state *uart_get(struct uart_driver *drv, int line) { struct uart_state *state; + int ret = 0; - mutex_lock(&port_mutex); state = drv->state + line; if (mutex_lock_interruptible(&state->mutex)) { - state = ERR_PTR(-ERESTARTSYS); - goto out; + ret = -ERESTARTSYS; + goto err; } state->count++; - if (!state->port) { - state->count--; - mutex_unlock(&state->mutex); - state = ERR_PTR(-ENXIO); - goto out; + if (!state->port || state->port->flags & UPF_DEAD) { + ret = -ENXIO; + goto err_unlock; } if (!state->info) { @@ -1531,15 +1529,17 @@ static struct uart_state *uart_get(struct uart_driver *drv, int line) tasklet_init(&state->info->tlet, uart_tasklet_action, (unsigned long)state); } else { - state->count--; - mutex_unlock(&state->mutex); - state = ERR_PTR(-ENOMEM); + ret = -ENOMEM; + goto err_unlock; } } - - out: - mutex_unlock(&port_mutex); return state; + + err_unlock: + state->count--; + mutex_unlock(&state->mutex); + err: + return ERR_PTR(ret); } /* @@ -2085,45 +2085,6 @@ uart_configure_port(struct uart_driver *drv, struct uart_state *state, } } -/* - * This reverses the effects of uart_configure_port, hanging up the - * port before removal. - */ -static void -uart_unconfigure_port(struct uart_driver *drv, struct uart_state *state) -{ - struct uart_port *port = state->port; - struct uart_info *info = state->info; - - if (info && info->tty) - tty_vhangup(info->tty); - - mutex_lock(&state->mutex); - - state->info = NULL; - - /* - * Free the port IO and memory resources, if any. - */ - if (port->type != PORT_UNKNOWN) - port->ops->release_port(port); - - /* - * Indicate that there isn't a port here anymore. - */ - port->type = PORT_UNKNOWN; - - /* - * Kill the tasklet, and free resources. - */ - if (info) { - tasklet_kill(&info->tlet); - kfree(info); - } - - mutex_unlock(&state->mutex); -} - static struct tty_operations uart_ops = { .open = uart_open, .close = uart_close, @@ -2270,6 +2231,7 @@ int uart_add_one_port(struct uart_driver *drv, struct uart_port *port) state = drv->state + port->line; mutex_lock(&port_mutex); + mutex_lock(&state->mutex); if (state->port) { ret = -EINVAL; goto out; @@ -2304,7 +2266,13 @@ int uart_add_one_port(struct uart_driver *drv, struct uart_port *port) port->cons && !(port->cons->flags & CON_ENABLED)) register_console(port->cons); + /* + * Ensure UPF_DEAD is not set. + */ + port->flags &= ~UPF_DEAD; + out: + mutex_unlock(&state->mutex); mutex_unlock(&port_mutex); return ret; @@ -2322,6 +2290,7 @@ int uart_add_one_port(struct uart_driver *drv, struct uart_port *port) int uart_remove_one_port(struct uart_driver *drv, struct uart_port *port) { struct uart_state *state = drv->state + port->line; + struct uart_info *info; BUG_ON(in_interrupt()); @@ -2332,11 +2301,48 @@ int uart_remove_one_port(struct uart_driver *drv, struct uart_port *port) mutex_lock(&port_mutex); /* + * Mark the port "dead" - this prevents any opens from + * succeeding while we shut down the port. + */ + mutex_lock(&state->mutex); + port->flags |= UPF_DEAD; + mutex_unlock(&state->mutex); + + /* * Remove the devices from devfs */ tty_unregister_device(drv->tty_driver, port->line); - uart_unconfigure_port(drv, state); + info = state->info; + if (info && info->tty) + tty_vhangup(info->tty); + + /* + * All users of this port should now be disconnected from + * this driver, and the port shut down. We should be the + * only thread fiddling with this port from now on. + */ + state->info = NULL; + + /* + * Free the port IO and memory resources, if any. + */ + if (port->type != PORT_UNKNOWN) + port->ops->release_port(port); + + /* + * Indicate that there isn't a port here anymore. + */ + port->type = PORT_UNKNOWN; + + /* + * Kill the tasklet, and free resources. + */ + if (info) { + tasklet_kill(&info->tlet); + kfree(info); + } + state->port = NULL; mutex_unlock(&port_mutex); diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index c32e60e..bd14858 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -254,6 +254,7 @@ struct uart_port { #define UPF_CONS_FLOW ((__force upf_t) (1 << 23)) #define UPF_SHARE_IRQ ((__force upf_t) (1 << 24)) #define UPF_BOOT_AUTOCONF ((__force upf_t) (1 << 28)) +#define UPF_DEAD ((__force upf_t) (1 << 30)) #define UPF_IOREMAP ((__force upf_t) (1 << 31)) #define UPF_CHANGE_MASK ((__force upf_t) (0x17fff)) |
