The patch titled
Delay creation of khcvd thread
has been added to the -mm tree. Its filename is
delay-creation-of-khcvd-thread.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: Delay creation of khcvd thread
From: Rusty Russell <rusty@xxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
diff -puN drivers/char/Kconfig~delay-creation-of-khcvd-thread drivers/char/Kconfig
--- a/drivers/char/Kconfig~delay-creation-of-khcvd-thread
+++ a/drivers/char/Kconfig
@@ -599,8 +599,8 @@ 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.
diff -puN drivers/char/hvc_console.c~delay-creation-of-khcvd-thread drivers/char/hvc_console.c
--- a/drivers/char/hvc_console.c~delay-creation-of-khcvd-thread
+++ a/drivers/char/hvc_console.c
@@ -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(u
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_stru
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);
_
Patches currently in -mm which might be from rusty@xxxxxxxxxxxxxxx are
fix-modules-oopsing-in-lguest-guests.patch
lguest-example-launcher-truncates-block-device-file-to-0.patch
git-kbuild.patch
git-kvm.patch
readahead-compacting-file_ra_state.patch
readahead-mmap-read-around-simplification.patch
readahead-combine-file_ra_stateprev_index-prev_offset-into-prev_pos.patch
readahead-combine-file_ra_stateprev_index-prev_offset-into-prev_pos-fix.patch
readahead-combine-file_ra_stateprev_index-prev_offset-into-prev_pos-fix-2.patch
radixtree-introduce-radix_tree_next_hole.patch
readahead-basic-support-of-interleaved-reads.patch
readahead-remove-the-local-copy-of-ra-in-do_generic_mapping_read.patch
readahead-remove-several-readahead-macros.patch
readahead-remove-the-limit-max_sectors_kb-imposed-on-max_readahead_kb.patch
filemap-trivial-code-cleanups.patch
filemap-convert-some-unsigned-long-to-pgoff_t.patch
mmaps2-vma-out-of-mem_size_stats.patch
maps2-make-proc-pid-smaps-optional-under-config_embeddedpatch.patch
maps2-make-proc-pid-smaps-optional-under-config_embeddedpatch-fix.patch
remove-unsafe-from-module-struct.patch
move-kasprintfo-to-obj-y.patch
delay-creation-of-khcvd-thread.patch
cpu-hotplug-cpu-deliver-cpu_up_canceled-only-to-notify_oked-callbacks-with-cpu_up_prepare.patch
mm-clean-up-and-kernelify-shrinker-registration-reiser4.patch
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