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Commit ad211790 authored by Peter Oberparleiter's avatar Peter Oberparleiter Committed by Heiko Carstens
Browse files

[S390] sclp: simplify vt220 cleanup logic 



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: default avatarPeter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: default avatarHeiko Carstens <heiko.carstens@de.ibm.com>
parent 773922e1

drivers/s390/char/sclp_vt220.c

+28 −27
Original line number Diff line number Diff line
@@ -82,8 +82,8 @@ static struct sclp_vt220_request *sclp_vt220_current_request; 
/* 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_struct *tty) 
	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(void) 
		else

			free_bootmem((unsigned long) page, PAGE_SIZE);

	}

	if (!list_empty(&sclp_vt220_register.list))

}



/* 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_initialized = 0;

	__sclp_vt220_free_pages();

}



static int __init __sclp_vt220_init(void)

/* 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(void) 
{

	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;
@@ -723,7 +726,6 @@ static int __init sclp_vt220_tty_init(void) 
	return 0;



out_init:

	if (cleanup)

	__sclp_vt220_cleanup();

out_driver:

	put_tty_driver(driver);
@@ -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 */