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Commit e8216dee authored by Heiko Carstens's avatar Heiko Carstens Committed by Linus Torvalds
Browse files

[PATCH] s390: fix cmm kernel thread handling 



Convert cmm's usage of kernel_thread to kthread_run.  Also create the
cmmthread at module load time, so it is possible to check if creation of
the thread fails.

In addition the cmmthread now gets terminated when the module gets unloaded
instead of leaving a stale kernel thread.  Also check the return values of
other registration functions at module load and handle their return values
appropriately.

Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent e8df8c33

arch/s390/mm/cmm.c

+35 −19
Original line number Diff line number Diff line
@@ -16,6 +16,7 @@ 
#include <linux/sysctl.h>

#include <linux/ctype.h>

#include <linux/swap.h>

#include <linux/kthread.h>



#include <asm/pgalloc.h>

#include <asm/uaccess.h>
@@ -46,8 +47,7 @@ static struct cmm_page_array *cmm_page_list; 
static struct cmm_page_array *cmm_timed_page_list;

static DEFINE_SPINLOCK(cmm_lock);



static unsigned long cmm_thread_active;

static struct work_struct cmm_thread_starter;

static struct task_struct *cmm_thread_ptr;

static wait_queue_head_t cmm_thread_wait;

static struct timer_list cmm_timer;
@@ -143,14 +143,12 @@ cmm_thread(void *dummy) 
{

	int rc;



	daemonize("cmmthread");

	while (1) {

		rc = wait_event_interruptible(cmm_thread_wait,

			(cmm_pages != cmm_pages_target ||

			 cmm_timed_pages != cmm_timed_pages_target));

		if (rc == -ERESTARTSYS) {

			/* Got kill signal. End thread. */

			clear_bit(0, &cmm_thread_active);

			 cmm_timed_pages != cmm_timed_pages_target ||

			 kthread_should_stop()));

		if (kthread_should_stop() || rc == -ERESTARTSYS) {

			cmm_pages_target = cmm_pages;

			cmm_timed_pages_target = cmm_timed_pages;

			break;
@@ -175,17 +173,9 @@ cmm_thread(void *dummy) 
	return 0;

}



static void

cmm_start_thread(void)

{

	kernel_thread(cmm_thread, NULL, 0);

}



static void

cmm_kick_thread(void)

{

	if (!test_and_set_bit(0, &cmm_thread_active))

		schedule_work(&cmm_thread_starter);

	wake_up(&cmm_thread_wait);

}
@@ -429,22 +419,48 @@ struct ctl_table_header *cmm_sysctl_header; 
static int

cmm_init (void)

{

	int rc = -ENOMEM;



#ifdef CONFIG_CMM_PROC

	cmm_sysctl_header = register_sysctl_table(cmm_dir_table, 1);

	if (!cmm_sysctl_header)

		goto out;

#endif

#ifdef CONFIG_CMM_IUCV

	smsg_register_callback(SMSG_PREFIX, cmm_smsg_target);

	rc = smsg_register_callback(SMSG_PREFIX, cmm_smsg_target);

	if (rc < 0)

		goto out_smsg;

#endif

	register_oom_notifier(&cmm_oom_nb);

	INIT_WORK(&cmm_thread_starter, (void *) cmm_start_thread, NULL);

	rc = register_oom_notifier(&cmm_oom_nb);

	if (rc < 0)

		goto out_oom_notify;

	init_waitqueue_head(&cmm_thread_wait);

	init_timer(&cmm_timer);

	return 0;

	cmm_thread_ptr = kthread_run(cmm_thread, NULL, "cmmthread");

	rc = IS_ERR(cmm_thread_ptr) ? PTR_ERR(cmm_thread_ptr) : 0;

	if (!rc)

		goto out;

	/*

	 * kthread_create failed. undo all the stuff from above again.

	 */

	unregister_oom_notifier(&cmm_oom_nb);



out_oom_notify:

#ifdef CONFIG_CMM_IUCV

	smsg_unregister_callback(SMSG_PREFIX, cmm_smsg_target);

out_smsg:

#endif

#ifdef CONFIG_CMM_PROC

	unregister_sysctl_table(cmm_sysctl_header);

#endif

out:

	return rc;

}



static void

cmm_exit(void)

{

	kthread_stop(cmm_thread_ptr);

	unregister_oom_notifier(&cmm_oom_nb);

	cmm_free_pages(cmm_pages, &cmm_pages, &cmm_page_list);

	cmm_free_pages(cmm_timed_pages, &cmm_timed_pages, &cmm_timed_page_list);