[mirror_ubuntu-artful-kernel.git] / drivers / video / fb_defio.c

/*
 *  linux/drivers/video/fb_defio.c
 *
 *  Copyright (C) 2006 Jaya Kumar
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License. See the file COPYING in the main directory of this archive
 * for more details.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/fb.h>
#include <linux/list.h>

/* to support deferred IO */
#include <linux/rmap.h>
#include <linux/pagemap.h>

/* this is to find and return the vmalloc-ed fb pages */
static int fb_deferred_io_fault(struct vm_area_struct *vma,
				struct vm_fault *vmf)
{
	unsigned long offset;
	struct page *page;
	struct fb_info *info = vma->vm_private_data;
	/* info->screen_base is virtual memory */
	void *screen_base = (void __force *) info->screen_base;

	offset = vmf->pgoff << PAGE_SHIFT;
	if (offset >= info->fix.smem_len)
		return VM_FAULT_SIGBUS;

	page = vmalloc_to_page(screen_base + offset);
	if (!page)
		return VM_FAULT_SIGBUS;

	get_page(page);

	if (vma->vm_file)
		page->mapping = vma->vm_file->f_mapping;
	else
		printk(KERN_ERR "no mapping available\n");

	BUG_ON(!page->mapping);
	page->index = vmf->pgoff;

	vmf->page = page;
	return 0;
}

int fb_deferred_io_fsync(struct file *file, struct dentry *dentry, int datasync)
{
	struct fb_info *info = file->private_data;

	/* Kill off the delayed work */
	cancel_rearming_delayed_work(&info->deferred_work);

	/* Run it immediately */
	return schedule_delayed_work(&info->deferred_work, 0);
}
EXPORT_SYMBOL_GPL(fb_deferred_io_fsync);

/* vm_ops->page_mkwrite handler */
static int fb_deferred_io_mkwrite(struct vm_area_struct *vma,
				  struct page *page)
{
	struct fb_info *info = vma->vm_private_data;
	struct fb_deferred_io *fbdefio = info->fbdefio;
	struct page *cur;

	/* this is a callback we get when userspace first tries to
	write to the page. we schedule a workqueue. that workqueue
	will eventually mkclean the touched pages and execute the
	deferred framebuffer IO. then if userspace touches a page
	again, we repeat the same scheme */

	/* protect against the workqueue changing the page list */
	mutex_lock(&fbdefio->lock);

	/* we loop through the pagelist before adding in order
	to keep the pagelist sorted */
	list_for_each_entry(cur, &fbdefio->pagelist, lru) {
		/* this check is to catch the case where a new
		process could start writing to the same page
		through a new pte. this new access can cause the
		mkwrite even when the original ps's pte is marked
		writable */
		if (unlikely(cur == page))
			goto page_already_added;
		else if (cur->index > page->index)
			break;
	}

	list_add_tail(&page->lru, &cur->lru);

page_already_added:
	mutex_unlock(&fbdefio->lock);

	/* come back after delay to process the deferred IO */
	schedule_delayed_work(&info->deferred_work, fbdefio->delay);
	return 0;
}

static struct vm_operations_struct fb_deferred_io_vm_ops = {
	.fault		= fb_deferred_io_fault,
	.page_mkwrite	= fb_deferred_io_mkwrite,
};

static int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma)
{
	vma->vm_ops = &fb_deferred_io_vm_ops;
	vma->vm_flags |= ( VM_IO | VM_RESERVED | VM_DONTEXPAND );
	vma->vm_private_data = info;
	return 0;
}

/* workqueue callback */
static void fb_deferred_io_work(struct work_struct *work)
{
	struct fb_info *info = container_of(work, struct fb_info,
						deferred_work.work);
	struct list_head *node, *next;
	struct page *cur;
	struct fb_deferred_io *fbdefio = info->fbdefio;

	/* here we mkclean the pages, then do all deferred IO */
	mutex_lock(&fbdefio->lock);
	list_for_each_entry(cur, &fbdefio->pagelist, lru) {
		lock_page(cur);
		page_mkclean(cur);
		unlock_page(cur);
	}

	/* driver's callback with pagelist */
	fbdefio->deferred_io(info, &fbdefio->pagelist);

	/* clear the list */
	list_for_each_safe(node, next, &fbdefio->pagelist) {
		list_del(node);
	}
	mutex_unlock(&fbdefio->lock);
}

void fb_deferred_io_init(struct fb_info *info)
{
	struct fb_deferred_io *fbdefio = info->fbdefio;

	BUG_ON(!fbdefio);
	mutex_init(&fbdefio->lock);
	info->fbops->fb_mmap = fb_deferred_io_mmap;
	INIT_DELAYED_WORK(&info->deferred_work, fb_deferred_io_work);
	INIT_LIST_HEAD(&fbdefio->pagelist);
	if (fbdefio->delay == 0) /* set a default of 1 s */
		fbdefio->delay = HZ;
}
EXPORT_SYMBOL_GPL(fb_deferred_io_init);

void fb_deferred_io_cleanup(struct fb_info *info)
{
	void *screen_base = (void __force *) info->screen_base;
	struct fb_deferred_io *fbdefio = info->fbdefio;
	struct page *page;
	int i;

	BUG_ON(!fbdefio);
	cancel_delayed_work(&info->deferred_work);
	flush_scheduled_work();

	/* clear out the mapping that we setup */
	for (i = 0 ; i < info->fix.smem_len; i += PAGE_SIZE) {
		page = vmalloc_to_page(screen_base + i);
		page->mapping = NULL;
	}
}
EXPORT_SYMBOL_GPL(fb_deferred_io_cleanup);

MODULE_LICENSE("GPL");
Commit	Line	Data
60b59bea JK	1	/*
	2	* linux/drivers/video/fb_defio.c
	3	*
	4	* Copyright (C) 2006 Jaya Kumar
	5	*
	6	* This file is subject to the terms and conditions of the GNU General Public
de7c6d15	7	* License. See the file COPYING in the main directory of this archive
60b59bea JK	8	* for more details.
	9	*/
	10
	11	#include <linux/module.h>
	12	#include <linux/kernel.h>
	13	#include <linux/errno.h>
	14	#include <linux/string.h>
	15	#include <linux/mm.h>
	16	#include <linux/slab.h>
	17	#include <linux/vmalloc.h>
	18	#include <linux/delay.h>
	19	#include <linux/interrupt.h>
	20	#include <linux/fb.h>
	21	#include <linux/list.h>
60b59bea JK	22
	23	/* to support deferred IO */
	24	#include <linux/rmap.h>
	25	#include <linux/pagemap.h>
	26
	27	/* this is to find and return the vmalloc-ed fb pages */
529e55b6 NP	28	static int fb_deferred_io_fault(struct vm_area_struct *vma,
529e55b6 NP	29	struct vm_fault *vmf)
60b59bea JK	30	{
	31	unsigned long offset;
	32	struct page *page;
	33	struct fb_info *info = vma->vm_private_data;
de7c6d15	34	/* info->screen_base is virtual memory */
98a1153a	35	void screen_base = (void __force ) info->screen_base;
60b59bea	36
529e55b6	37	offset = vmf->pgoff << PAGE_SHIFT;
60b59bea	38	if (offset >= info->fix.smem_len)
529e55b6	39	return VM_FAULT_SIGBUS;
60b59bea	40
98a1153a	41	page = vmalloc_to_page(screen_base + offset);
60b59bea	42	if (!page)
529e55b6	43	return VM_FAULT_SIGBUS;
60b59bea JK	44
60b59bea JK	45	get_page(page);
de7c6d15 JK	46
	47	if (vma->vm_file)
	48	page->mapping = vma->vm_file->f_mapping;
	49	else
	50	printk(KERN_ERR "no mapping available\n");
	51
	52	BUG_ON(!page->mapping);
	53	page->index = vmf->pgoff;
	54
529e55b6 NP	55	vmf->page = page;
529e55b6 NP	56	return 0;
60b59bea JK	57	}
60b59bea JK	58
5e841b88 PM	59	int fb_deferred_io_fsync(struct file file, struct dentry dentry, int datasync)
	60	{
	61	struct fb_info *info = file->private_data;
	62
	63	/* Kill off the delayed work */
	64	cancel_rearming_delayed_work(&info->deferred_work);
	65
	66	/* Run it immediately */
	67	return schedule_delayed_work(&info->deferred_work, 0);
	68	}
	69	EXPORT_SYMBOL_GPL(fb_deferred_io_fsync);
	70
60b59bea	71	/* vm_ops->page_mkwrite handler */
7bf1ea33 AB	72	static int fb_deferred_io_mkwrite(struct vm_area_struct *vma,
7bf1ea33 AB	73	struct page *page)
60b59bea JK	74	{
	75	struct fb_info *info = vma->vm_private_data;
	76	struct fb_deferred_io *fbdefio = info->fbdefio;
f31ad92f	77	struct page *cur;
60b59bea JK	78
	79	/* this is a callback we get when userspace first tries to
	80	write to the page. we schedule a workqueue. that workqueue
	81	will eventually mkclean the touched pages and execute the
	82	deferred framebuffer IO. then if userspace touches a page
	83	again, we repeat the same scheme */
	84
	85	/* protect against the workqueue changing the page list */
	86	mutex_lock(&fbdefio->lock);
f31ad92f JK	87
	88	/* we loop through the pagelist before adding in order
	89	to keep the pagelist sorted */
	90	list_for_each_entry(cur, &fbdefio->pagelist, lru) {
	91	/* this check is to catch the case where a new
	92	process could start writing to the same page
	93	through a new pte. this new access can cause the
	94	mkwrite even when the original ps's pte is marked
	95	writable */
	96	if (unlikely(cur == page))
	97	goto page_already_added;
	98	else if (cur->index > page->index)
	99	break;
	100	}
	101
	102	list_add_tail(&page->lru, &cur->lru);
	103
	104	page_already_added:
60b59bea JK	105	mutex_unlock(&fbdefio->lock);
	106
	107	/* come back after delay to process the deferred IO */
	108	schedule_delayed_work(&info->deferred_work, fbdefio->delay);
	109	return 0;
	110	}
	111
	112	static struct vm_operations_struct fb_deferred_io_vm_ops = {
529e55b6	113	.fault = fb_deferred_io_fault,
60b59bea JK	114	.page_mkwrite = fb_deferred_io_mkwrite,
	115	};
	116
	117	static int fb_deferred_io_mmap(struct fb_info info, struct vm_area_struct vma)
	118	{
	119	vma->vm_ops = &fb_deferred_io_vm_ops;
	120	vma->vm_flags \|= ( VM_IO \| VM_RESERVED \| VM_DONTEXPAND );
	121	vma->vm_private_data = info;
	122	return 0;
	123	}
	124
	125	/* workqueue callback */
	126	static void fb_deferred_io_work(struct work_struct *work)
	127	{
	128	struct fb_info *info = container_of(work, struct fb_info,
	129	deferred_work.work);
	130	struct list_head node, next;
	131	struct page *cur;
	132	struct fb_deferred_io *fbdefio = info->fbdefio;
	133
	134	/* here we mkclean the pages, then do all deferred IO */
	135	mutex_lock(&fbdefio->lock);
	136	list_for_each_entry(cur, &fbdefio->pagelist, lru) {
	137	lock_page(cur);
	138	page_mkclean(cur);
	139	unlock_page(cur);
	140	}
	141
	142	/* driver's callback with pagelist */
	143	fbdefio->deferred_io(info, &fbdefio->pagelist);
	144
	145	/* clear the list */
	146	list_for_each_safe(node, next, &fbdefio->pagelist) {
	147	list_del(node);
	148	}
	149	mutex_unlock(&fbdefio->lock);
	150	}
	151
	152	void fb_deferred_io_init(struct fb_info *info)
	153	{
	154	struct fb_deferred_io *fbdefio = info->fbdefio;
	155
	156	BUG_ON(!fbdefio);
	157	mutex_init(&fbdefio->lock);
	158	info->fbops->fb_mmap = fb_deferred_io_mmap;
	159	INIT_DELAYED_WORK(&info->deferred_work, fb_deferred_io_work);
	160	INIT_LIST_HEAD(&fbdefio->pagelist);
	161	if (fbdefio->delay == 0) /* set a default of 1 s */
	162	fbdefio->delay = HZ;
	163	}
	164	EXPORT_SYMBOL_GPL(fb_deferred_io_init);
	165
	166	void fb_deferred_io_cleanup(struct fb_info *info)
	167	{
de7c6d15	168	void screen_base = (void __force ) info->screen_base;
60b59bea	169	struct fb_deferred_io *fbdefio = info->fbdefio;
de7c6d15 JK	170	struct page *page;
de7c6d15 JK	171	int i;
60b59bea JK	172
	173	BUG_ON(!fbdefio);
	174	cancel_delayed_work(&info->deferred_work);
	175	flush_scheduled_work();
de7c6d15 JK	176
	177	/* clear out the mapping that we setup */
	178	for (i = 0 ; i < info->fix.smem_len; i += PAGE_SIZE) {
	179	page = vmalloc_to_page(screen_base + i);
	180	page->mapping = NULL;
	181	}
60b59bea JK	182	}
	183	EXPORT_SYMBOL_GPL(fb_deferred_io_cleanup);
	184
	185	MODULE_LICENSE("GPL");