From: Peter Oberparleiter <[email protected]>
Fix a number of sclp_vt220 cleanup problems:
* fix list_empty check after list_del()
* mark init-only flag as __initdata
* remove implicit dependency between slab_available() and num_pages
* straighten multiple init handling (use init count)
Signed-off-by: Peter Oberparleiter <[email protected]>
Signed-off-by: Martin Schwidefsky <[email protected]>
---
drivers/s390/char/sclp_vt220.c | 55 ++++++++++++++++++++---------------------
1 file changed, 28 insertions(+), 27 deletions(-)
Index: quilt-2.6/drivers/s390/char/sclp_vt220.c
===================================================================
--- quilt-2.6.orig/drivers/s390/char/sclp_vt220.c
+++ quilt-2.6/drivers/s390/char/sclp_vt220.c
@@ -82,8 +82,8 @@ static struct sclp_vt220_request *sclp_v
/* Number of characters in current request buffer */
static int sclp_vt220_buffered_chars;
-/* Flag indicating whether this driver has already been initialized */
-static int sclp_vt220_initialized = 0;
+/* Counter controlling core driver initialization. */
+static int __initdata sclp_vt220_init_count;
/* Flag indicating that sclp_vt220_current_request should really
* have been already queued but wasn't because the SCLP was processing
@@ -609,10 +609,8 @@ sclp_vt220_flush_buffer(struct tty_struc
sclp_vt220_emit_current();
}
-/*
- * Initialize all relevant components and register driver with system.
- */
-static void __init __sclp_vt220_cleanup(void)
+/* Release allocated pages. */
+static void __init __sclp_vt220_free_pages(void)
{
struct list_head *page, *p;
@@ -623,21 +621,30 @@ static void __init __sclp_vt220_cleanup(
else
free_bootmem((unsigned long) page, PAGE_SIZE);
}
- if (!list_empty(&sclp_vt220_register.list))
- sclp_unregister(&sclp_vt220_register);
- sclp_vt220_initialized = 0;
}
-static int __init __sclp_vt220_init(void)
+/* Release memory and unregister from sclp core. Controlled by init counting -
+ * only the last invoker will actually perform these actions. */
+static void __init __sclp_vt220_cleanup(void)
+{
+ sclp_vt220_init_count--;
+ if (sclp_vt220_init_count != 0)
+ return;
+ sclp_unregister(&sclp_vt220_register);
+ __sclp_vt220_free_pages();
+}
+
+/* Allocate buffer pages and register with sclp core. Controlled by init
+ * counting - only the first invoker will actually perform these actions. */
+static int __init __sclp_vt220_init(int num_pages)
{
void *page;
int i;
- int num_pages;
int rc;
- if (sclp_vt220_initialized)
+ sclp_vt220_init_count++;
+ if (sclp_vt220_init_count != 1)
return 0;
- sclp_vt220_initialized = 1;
spin_lock_init(&sclp_vt220_lock);
INIT_LIST_HEAD(&sclp_vt220_empty);
INIT_LIST_HEAD(&sclp_vt220_outqueue);
@@ -649,24 +656,22 @@ static int __init __sclp_vt220_init(void
sclp_vt220_flush_later = 0;
/* Allocate pages for output buffering */
- num_pages = slab_is_available() ? MAX_KMEM_PAGES : MAX_CONSOLE_PAGES;
for (i = 0; i < num_pages; i++) {
if (slab_is_available())
page = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
else
page = alloc_bootmem_low_pages(PAGE_SIZE);
if (!page) {
- __sclp_vt220_cleanup();
- return -ENOMEM;
+ rc = -ENOMEM;
+ goto out;
}
list_add_tail((struct list_head *) page, &sclp_vt220_empty);
}
rc = sclp_register(&sclp_vt220_register);
+out:
if (rc) {
- printk(KERN_ERR SCLP_VT220_PRINT_HEADER
- "could not register vt220 - "
- "sclp_register returned %d\n", rc);
- __sclp_vt220_cleanup();
+ __sclp_vt220_free_pages();
+ sclp_vt220_init_count--;
}
return rc;
}
@@ -689,15 +694,13 @@ static int __init sclp_vt220_tty_init(vo
{
struct tty_driver *driver;
int rc;
- int cleanup;
/* Note: we're not testing for CONSOLE_IS_SCLP here to preserve
* symmetry between VM and LPAR systems regarding ttyS1. */
driver = alloc_tty_driver(1);
if (!driver)
return -ENOMEM;
- cleanup = !sclp_vt220_initialized;
- rc = __sclp_vt220_init();
+ rc = __sclp_vt220_init(MAX_KMEM_PAGES);
if (rc)
goto out_driver;
@@ -723,8 +726,7 @@ static int __init sclp_vt220_tty_init(vo
return 0;
out_init:
- if (cleanup)
- __sclp_vt220_cleanup();
+ __sclp_vt220_cleanup();
out_driver:
put_tty_driver(driver);
return rc;
@@ -773,10 +775,9 @@ sclp_vt220_con_init(void)
{
int rc;
- INIT_LIST_HEAD(&sclp_vt220_register.list);
if (!CONSOLE_IS_SCLP)
return 0;
- rc = __sclp_vt220_init();
+ rc = __sclp_vt220_init(MAX_CONSOLE_PAGES);
if (rc)
return rc;
/* Attach linux console */
--
blue skies,
Martin.
"Reality continues to ruin my life." - Calvin.