1 files changed, 128 insertions, 77 deletions

diff --git a/arch/s390/mm/cmm.c b/arch/s390/mm/cmm.c
index 786a44dba5b..607f50ead1f 100644
--- a/arch/s390/mm/cmm.c
+++ b/arch/s390/mm/cmm.c
@@ -15,6 +15,8 @@
 #include <linux/sched.h>
 #include <linux/sysctl.h>
 #include <linux/ctype.h>
+#include <linux/swap.h>
+#include <linux/kthread.h>
 
 #include <asm/pgalloc.h>
 #include <asm/uaccess.h>
@@ -34,18 +36,18 @@ struct cmm_page_array {
 	unsigned long pages[CMM_NR_PAGES];
 };
 
-static long cmm_pages = 0;
-static long cmm_timed_pages = 0;
-static volatile long cmm_pages_target = 0;
-static volatile long cmm_timed_pages_target = 0;
-static long cmm_timeout_pages = 0;
-static long cmm_timeout_seconds = 0;
+static long cmm_pages;
+static long cmm_timed_pages;
+static volatile long cmm_pages_target;
+static volatile long cmm_timed_pages_target;
+static long cmm_timeout_pages;
+static long cmm_timeout_seconds;
 
-static struct cmm_page_array *cmm_page_list = NULL;
-static struct cmm_page_array *cmm_timed_page_list = NULL;
+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 = 0;
-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;
 
@@ -53,71 +55,100 @@ static void cmm_timer_fn(unsigned long);
 static void cmm_set_timer(void);
 
 static long
-cmm_alloc_pages(long pages, long *counter, struct cmm_page_array **list)
+cmm_alloc_pages(long nr, long *counter, struct cmm_page_array **list)
 {
-	struct cmm_page_array *pa;
-	unsigned long page;
+	struct cmm_page_array *pa, *npa;
+	unsigned long addr;
 
-	pa = *list;
-	while (pages) {
-		page = __get_free_page(GFP_NOIO);
-		if (!page)
+	while (nr) {
+		addr = __get_free_page(GFP_NOIO);
+		if (!addr)
 			break;
+		spin_lock(&cmm_lock);
+		pa = *list;
 		if (!pa || pa->index >= CMM_NR_PAGES) {
 			/* Need a new page for the page list. */
-			pa = (struct cmm_page_array *)
+			spin_unlock(&cmm_lock);
+			npa = (struct cmm_page_array *)
 				__get_free_page(GFP_NOIO);
-			if (!pa) {
-				free_page(page);
+			if (!npa) {
+				free_page(addr);
 				break;
 			}
-			pa->next = *list;
-			pa->index = 0;
-			*list = pa;
+			spin_lock(&cmm_lock);
+			pa = *list;
+			if (!pa || pa->index >= CMM_NR_PAGES) {
+				npa->next = pa;
+				npa->index = 0;
+				pa = npa;
+				*list = pa;
+			} else
+				free_page((unsigned long) npa);
 		}
-		diag10(page);
-		pa->pages[pa->index++] = page;
+		diag10(addr);
+		pa->pages[pa->index++] = addr;
 		(*counter)++;
-		pages--;
+		spin_unlock(&cmm_lock);
+		nr--;
 	}
-	return pages;
+	return nr;
 }
 
-static void
-cmm_free_pages(long pages, long *counter, struct cmm_page_array **list)
+static long
+cmm_free_pages(long nr, long *counter, struct cmm_page_array **list)
 {
 	struct cmm_page_array *pa;
-	unsigned long page;
+	unsigned long addr;
 
+	spin_lock(&cmm_lock);
 	pa = *list;
-	while (pages) {
+	while (nr) {
 		if (!pa || pa->index <= 0)
 			break;
-		page = pa->pages[--pa->index];
+		addr = pa->pages[--pa->index];
 		if (pa->index == 0) {
 			pa = pa->next;
 			free_page((unsigned long) *list);
 			*list = pa;
 		}
-		free_page(page);
+		free_page(addr);
 		(*counter)--;
-		pages--;
+		nr--;
 	}
+	spin_unlock(&cmm_lock);
+	return nr;
 }
 
+static int cmm_oom_notify(struct notifier_block *self,
+			  unsigned long dummy, void *parm)
+{
+	unsigned long *freed = parm;
+	long nr = 256;
+
+	nr = cmm_free_pages(nr, &cmm_timed_pages, &cmm_timed_page_list);
+	if (nr > 0)
+		nr = cmm_free_pages(nr, &cmm_pages, &cmm_page_list);
+	cmm_pages_target = cmm_pages;
+	cmm_timed_pages_target = cmm_timed_pages;
+	*freed += 256 - nr;
+	return NOTIFY_OK;
+}
+
+static struct notifier_block cmm_oom_nb = {
+	.notifier_call = cmm_oom_notify
+};
+
 static int
 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;
@@ -143,16 +174,8 @@ cmm_thread(void *dummy)
 }
 
 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);
 }
 
@@ -177,21 +200,21 @@ cmm_set_timer(void)
 static void
 cmm_timer_fn(unsigned long ignored)
 {
-	long pages;
+	long nr;
 
-	pages = cmm_timed_pages_target - cmm_timeout_pages;
-	if (pages < 0)
+	nr = cmm_timed_pages_target - cmm_timeout_pages;
+	if (nr < 0)
 		cmm_timed_pages_target = 0;
 	else
-		cmm_timed_pages_target = pages;
+		cmm_timed_pages_target = nr;
 	cmm_kick_thread();
 	cmm_set_timer();
 }
 
 void
-cmm_set_pages(long pages)
+cmm_set_pages(long nr)
 {
-	cmm_pages_target = pages;
+	cmm_pages_target = nr;
 	cmm_kick_thread();
 }
 
@@ -202,9 +225,9 @@ cmm_get_pages(void)
 }
 
 void
-cmm_add_timed_pages(long pages)
+cmm_add_timed_pages(long nr)
 {
-	cmm_timed_pages_target += pages;
+	cmm_timed_pages_target += nr;
 	cmm_kick_thread();
 }
 
@@ -215,9 +238,9 @@ cmm_get_timed_pages(void)
 }
 
 void
-cmm_set_timeout(long pages, long seconds)
+cmm_set_timeout(long nr, long seconds)
 {
-	cmm_timeout_pages = pages;
+	cmm_timeout_pages = nr;
 	cmm_timeout_seconds = seconds;
 	cmm_set_timer();
 }
@@ -245,7 +268,7 @@ cmm_pages_handler(ctl_table *ctl, int write, struct file *filp,
 		  void __user *buffer, size_t *lenp, loff_t *ppos)
 {
 	char buf[16], *p;
-	long pages;
+	long nr;
 	int len;
 
 	if (!*lenp || (*ppos && !write)) {
@@ -260,17 +283,17 @@ cmm_pages_handler(ctl_table *ctl, int write, struct file *filp,
 			return -EFAULT;
 		buf[sizeof(buf) - 1] = '\0';
 		cmm_skip_blanks(buf, &p);
-		pages = simple_strtoul(p, &p, 0);
+		nr = simple_strtoul(p, &p, 0);
 		if (ctl == &cmm_table[0])
-			cmm_set_pages(pages);
+			cmm_set_pages(nr);
 		else
-			cmm_add_timed_pages(pages);
+			cmm_add_timed_pages(nr);
 	} else {
 		if (ctl == &cmm_table[0])
-			pages = cmm_get_pages();
+			nr = cmm_get_pages();
 		else
-			pages = cmm_get_timed_pages();
-		len = sprintf(buf, "%ld\n", pages);
+			nr = cmm_get_timed_pages();
+		len = sprintf(buf, "%ld\n", nr);
 		if (len > *lenp)
 			len = *lenp;
 		if (copy_to_user(buffer, buf, len))
@@ -286,7 +309,7 @@ cmm_timeout_handler(ctl_table *ctl, int write, struct file *filp,
 		    void __user *buffer, size_t *lenp, loff_t *ppos)
 {
 	char buf[64], *p;
-	long pages, seconds;
+	long nr, seconds;
 	int len;
 
 	if (!*lenp || (*ppos && !write)) {
@@ -301,10 +324,10 @@ cmm_timeout_handler(ctl_table *ctl, int write, struct file *filp,
 			return -EFAULT;
 		buf[sizeof(buf) - 1] = '\0';
 		cmm_skip_blanks(buf, &p);
-		pages = simple_strtoul(p, &p, 0);
+		nr = simple_strtoul(p, &p, 0);
 		cmm_skip_blanks(p, &p);
 		seconds = simple_strtoul(p, &p, 0);
-		cmm_set_timeout(pages, seconds);
+		cmm_set_timeout(nr, seconds);
 	} else {
 		len = sprintf(buf, "%ld %ld\n",
 			      cmm_timeout_pages, cmm_timeout_seconds);
@@ -357,7 +380,7 @@ static struct ctl_table cmm_dir_table[] = {
 static void
 cmm_smsg_target(char *from, char *msg)
 {
-	long pages, seconds;
+	long nr, seconds;
 
 	if (strlen(sender) > 0 && strcmp(from, sender) != 0)
 		return;
@@ -366,27 +389,27 @@ cmm_smsg_target(char *from, char *msg)
 	if (strncmp(msg, "SHRINK", 6) == 0) {
 		if (!cmm_skip_blanks(msg + 6, &msg))
 			return;
-		pages = simple_strtoul(msg, &msg, 0);
+		nr = simple_strtoul(msg, &msg, 0);
 		cmm_skip_blanks(msg, &msg);
 		if (*msg == '\0')
-			cmm_set_pages(pages);
+			cmm_set_pages(nr);
 	} else if (strncmp(msg, "RELEASE", 7) == 0) {
 		if (!cmm_skip_blanks(msg + 7, &msg))
 			return;
-		pages = simple_strtoul(msg, &msg, 0);
+		nr = simple_strtoul(msg, &msg, 0);
 		cmm_skip_blanks(msg, &msg);
 		if (*msg == '\0')
-			cmm_add_timed_pages(pages);
+			cmm_add_timed_pages(nr);
 	} else if (strncmp(msg, "REUSE", 5) == 0) {
 		if (!cmm_skip_blanks(msg + 5, &msg))
 			return;
-		pages = simple_strtoul(msg, &msg, 0);
+		nr = simple_strtoul(msg, &msg, 0);
 		if (!cmm_skip_blanks(msg, &msg))
 			return;
 		seconds = simple_strtoul(msg, &msg, 0);
 		cmm_skip_blanks(msg, &msg);
 		if (*msg == '\0')
-			cmm_set_timeout(pages, seconds);
+			cmm_set_timeout(nr, seconds);
 	}
 }
 #endif
@@ -396,21 +419,49 @@ 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
-	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);
 #ifdef CONFIG_CMM_PROC