Delay creation of khcvd thread
This changes hvc_init() to be called only when someone actually uses the hvc_console driver. Dave Jones complained when profiling bootup. hvc_console used to only be for Power aka pSeries: now lguest and Xen both want it built-in in case the kernel is a guest under one of those, even though usually it will be a native boot. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
parent
fd5eea4214
commit
3e6c6f630a
|
@ -585,8 +585,8 @@ config TIPAR
|
|||
config HVC_DRIVER
|
||||
bool
|
||||
help
|
||||
Users of pSeries machines that want to utilize the hvc console front-end
|
||||
module for their backend console driver should select this option.
|
||||
Generic "hypervisor virtual console" infrastructure for various
|
||||
hypervisors (pSeries, Xen, lguest).
|
||||
It will automatically be selected if one of the back-end console drivers
|
||||
is selected.
|
||||
|
||||
|
|
|
@ -69,6 +69,8 @@ static struct task_struct *hvc_task;
|
|||
/* Picks up late kicks after list walk but before schedule() */
|
||||
static int hvc_kicked;
|
||||
|
||||
static int hvc_init(void);
|
||||
|
||||
#ifdef CONFIG_MAGIC_SYSRQ
|
||||
static int sysrq_pressed;
|
||||
#endif
|
||||
|
@ -754,6 +756,13 @@ struct hvc_struct __devinit *hvc_alloc(uint32_t vtermno, int irq,
|
|||
struct hvc_struct *hp;
|
||||
int i;
|
||||
|
||||
/* We wait until a driver actually comes along */
|
||||
if (!hvc_driver) {
|
||||
int err = hvc_init();
|
||||
if (err)
|
||||
return ERR_PTR(err);
|
||||
}
|
||||
|
||||
hp = kmalloc(ALIGN(sizeof(*hp), sizeof(long)) + outbuf_size,
|
||||
GFP_KERNEL);
|
||||
if (!hp)
|
||||
|
@ -829,16 +838,18 @@ int __devexit hvc_remove(struct hvc_struct *hp)
|
|||
return 0;
|
||||
}
|
||||
|
||||
/* Driver initialization. Follow console initialization. This is where the TTY
|
||||
* interfaces start to become available. */
|
||||
static int __init hvc_init(void)
|
||||
/* Driver initialization: called as soon as someone uses hvc_alloc(). */
|
||||
static int hvc_init(void)
|
||||
{
|
||||
struct tty_driver *drv;
|
||||
int err;
|
||||
|
||||
/* We need more than hvc_count adapters due to hotplug additions. */
|
||||
drv = alloc_tty_driver(HVC_ALLOC_TTY_ADAPTERS);
|
||||
if (!drv)
|
||||
return -ENOMEM;
|
||||
if (!drv) {
|
||||
err = -ENOMEM;
|
||||
goto out;
|
||||
}
|
||||
|
||||
drv->owner = THIS_MODULE;
|
||||
drv->driver_name = "hvc";
|
||||
|
@ -854,30 +865,43 @@ static int __init hvc_init(void)
|
|||
* added later. */
|
||||
hvc_task = kthread_run(khvcd, NULL, "khvcd");
|
||||
if (IS_ERR(hvc_task)) {
|
||||
panic("Couldn't create kthread for console.\n");
|
||||
put_tty_driver(drv);
|
||||
return -EIO;
|
||||
printk(KERN_ERR "Couldn't create kthread for console.\n");
|
||||
err = PTR_ERR(hvc_task);
|
||||
goto put_tty;
|
||||
}
|
||||
|
||||
if (tty_register_driver(drv))
|
||||
panic("Couldn't register hvc console driver\n");
|
||||
err = tty_register_driver(drv);
|
||||
if (err) {
|
||||
printk(KERN_ERR "Couldn't register hvc console driver\n");
|
||||
goto stop_thread;
|
||||
}
|
||||
|
||||
/* FIXME: This mb() seems completely random. Remove it. */
|
||||
mb();
|
||||
hvc_driver = drv;
|
||||
return 0;
|
||||
|
||||
put_tty:
|
||||
put_tty_driver(hvc_driver);
|
||||
stop_thread:
|
||||
kthread_stop(hvc_task);
|
||||
hvc_task = NULL;
|
||||
out:
|
||||
return err;
|
||||
}
|
||||
module_init(hvc_init);
|
||||
|
||||
/* This isn't particularly necessary due to this being a console driver
|
||||
* but it is nice to be thorough.
|
||||
*/
|
||||
static void __exit hvc_exit(void)
|
||||
{
|
||||
kthread_stop(hvc_task);
|
||||
if (hvc_driver) {
|
||||
kthread_stop(hvc_task);
|
||||
|
||||
tty_unregister_driver(hvc_driver);
|
||||
/* return tty_struct instances allocated in hvc_init(). */
|
||||
put_tty_driver(hvc_driver);
|
||||
unregister_console(&hvc_con_driver);
|
||||
tty_unregister_driver(hvc_driver);
|
||||
/* return tty_struct instances allocated in hvc_init(). */
|
||||
put_tty_driver(hvc_driver);
|
||||
unregister_console(&hvc_con_driver);
|
||||
}
|
||||
}
|
||||
module_exit(hvc_exit);
|
||||
|
|
Loading…
Reference in a new issue