[net-next-2.6.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/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>

struct page *fb_deferred_io_page(struct fb_info *info, unsigned long offs)
{
	void *screen_base = (void __force *) info->screen_base;
	struct page *page;

	if (is_vmalloc_addr(screen_base + offs))
		page = vmalloc_to_page(screen_base + offs);
	else
		page = pfn_to_page((info->fix.smem_start + offs) >> PAGE_SHIFT);

	return page;
}

/* 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;

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

	page = fb_deferred_io_page(info, 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;

	/* Skip if deferred io is compiled-in but disabled on this fbdev */
	if (!info->fbdefio)
		return 0;

	/* 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 vm_fault *vmf)
{
	struct page *page = vmf->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 const 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_set_page_dirty(struct page *page)
{
	if (!PageDirty(page))
		SetPageDirty(page);
	return 0;
}

static const struct address_space_operations fb_deferred_io_aops = {
	.set_page_dirty = fb_deferred_io_set_page_dirty,
};

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_RESERVED | VM_DONTEXPAND );
	if (!(info->flags & FBINFO_VIRTFB))
		vma->vm_flags |= VM_IO;
	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 fb_deferred_io *fbdefio = info->fbdefio;
	struct page *page, *tmp_page;
	struct list_head *node, *tmp_node;
	struct list_head non_dirty;

	INIT_LIST_HEAD(&non_dirty);

	/* here we mkclean the pages, then do all deferred IO */
	mutex_lock(&fbdefio->lock);
	list_for_each_entry_safe(page, tmp_page, &fbdefio->pagelist, lru) {
		lock_page(page);
		/*
		 * The workqueue callback can be triggered after a
		 * ->page_mkwrite() call but before the PTE has been marked
		 * dirty. In this case page_mkclean() won't "rearm" the page.
		 *
		 * To avoid this, remove those "non-dirty" pages from the
		 * pagelist before calling the driver's callback, then add
		 * them back to get processed on the next work iteration.
		 * At that time, their PTEs will hopefully be dirty for real.
		 */
		if (!page_mkclean(page))
			list_move_tail(&page->lru, &non_dirty);
		unlock_page(page);
	}

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

	/* clear the list... */
	list_for_each_safe(node, tmp_node, &fbdefio->pagelist) {
		list_del(node);
	}
	/* ... and add back the "non-dirty" pages to the list */
	list_splice_tail(&non_dirty, &fbdefio->pagelist);
	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_open(struct fb_info *info,
			 struct inode *inode,
			 struct file *file)
{
	file->f_mapping->a_ops = &fb_deferred_io_aops;
}
EXPORT_SYMBOL_GPL(fb_deferred_io_open);

void fb_deferred_io_cleanup(struct fb_info *info)
{
	struct fb_deferred_io *fbdefio = info->fbdefio;
	struct list_head *node, *tmp_node;
	struct page *page;
	int i;

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

	/*  the list may have still some non-dirty pages at this point */
	mutex_lock(&fbdefio->lock);
	list_for_each_safe(node, tmp_node, &fbdefio->pagelist) {
		list_del(node);
	}
	mutex_unlock(&fbdefio->lock);

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

	info->fbops->fb_mmap = NULL;
	mutex_destroy(&fbdefio->lock);
}
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>
60b59bea JK	16	#include <linux/vmalloc.h>
	17	#include <linux/delay.h>
	18	#include <linux/interrupt.h>
	19	#include <linux/fb.h>
	20	#include <linux/list.h>
60b59bea JK	21
	22	/* to support deferred IO */
	23	#include <linux/rmap.h>
	24	#include <linux/pagemap.h>
	25
37b48379 MD	26	struct page fb_deferred_io_page(struct fb_info info, unsigned long offs)
	27	{
	28	void screen_base = (void __force ) info->screen_base;
	29	struct page *page;
	30
	31	if (is_vmalloc_addr(screen_base + offs))
	32	page = vmalloc_to_page(screen_base + offs);
	33	else
	34	page = pfn_to_page((info->fix.smem_start + offs) >> PAGE_SHIFT);
	35
	36	return page;
	37	}
	38
60b59bea	39	/* this is to find and return the vmalloc-ed fb pages */
529e55b6 NP	40	static int fb_deferred_io_fault(struct vm_area_struct *vma,
529e55b6 NP	41	struct vm_fault *vmf)
60b59bea JK	42	{
	43	unsigned long offset;
	44	struct page *page;
	45	struct fb_info *info = vma->vm_private_data;
	46
529e55b6	47	offset = vmf->pgoff << PAGE_SHIFT;
60b59bea	48	if (offset >= info->fix.smem_len)
529e55b6	49	return VM_FAULT_SIGBUS;
60b59bea	50
37b48379	51	page = fb_deferred_io_page(info, offset);
60b59bea	52	if (!page)
529e55b6	53	return VM_FAULT_SIGBUS;
60b59bea JK	54
60b59bea JK	55	get_page(page);
de7c6d15 JK	56
	57	if (vma->vm_file)
	58	page->mapping = vma->vm_file->f_mapping;
	59	else
	60	printk(KERN_ERR "no mapping available\n");
	61
	62	BUG_ON(!page->mapping);
	63	page->index = vmf->pgoff;
	64
529e55b6 NP	65	vmf->page = page;
529e55b6 NP	66	return 0;
60b59bea JK	67	}
60b59bea JK	68
5e841b88 PM	69	int fb_deferred_io_fsync(struct file file, struct dentry dentry, int datasync)
	70	{
	71	struct fb_info *info = file->private_data;
	72
94e2bd68	73	/* Skip if deferred io is compiled-in but disabled on this fbdev */
87884bd8 MD	74	if (!info->fbdefio)
	75	return 0;
	76
5e841b88 PM	77	/* Kill off the delayed work */
	78	cancel_rearming_delayed_work(&info->deferred_work);
	79
	80	/* Run it immediately */
	81	return schedule_delayed_work(&info->deferred_work, 0);
	82	}
	83	EXPORT_SYMBOL_GPL(fb_deferred_io_fsync);
	84
60b59bea	85	/* vm_ops->page_mkwrite handler */
7bf1ea33	86	static int fb_deferred_io_mkwrite(struct vm_area_struct *vma,
c2ec175c	87	struct vm_fault *vmf)
60b59bea	88	{
c2ec175c	89	struct page *page = vmf->page;
60b59bea JK	90	struct fb_info *info = vma->vm_private_data;
60b59bea JK	91	struct fb_deferred_io *fbdefio = info->fbdefio;
f31ad92f	92	struct page *cur;
60b59bea JK	93
	94	/* this is a callback we get when userspace first tries to
	95	write to the page. we schedule a workqueue. that workqueue
	96	will eventually mkclean the touched pages and execute the
	97	deferred framebuffer IO. then if userspace touches a page
	98	again, we repeat the same scheme */
	99
	100	/* protect against the workqueue changing the page list */
	101	mutex_lock(&fbdefio->lock);
f31ad92f JK	102
	103	/* we loop through the pagelist before adding in order
	104	to keep the pagelist sorted */
	105	list_for_each_entry(cur, &fbdefio->pagelist, lru) {
	106	/* this check is to catch the case where a new
	107	process could start writing to the same page
	108	through a new pte. this new access can cause the
	109	mkwrite even when the original ps's pte is marked
	110	writable */
	111	if (unlikely(cur == page))
	112	goto page_already_added;
	113	else if (cur->index > page->index)
	114	break;
	115	}
	116
	117	list_add_tail(&page->lru, &cur->lru);
	118
	119	page_already_added:
60b59bea JK	120	mutex_unlock(&fbdefio->lock);
	121
	122	/* come back after delay to process the deferred IO */
	123	schedule_delayed_work(&info->deferred_work, fbdefio->delay);
	124	return 0;
	125	}
	126
f0f37e2f	127	static const struct vm_operations_struct fb_deferred_io_vm_ops = {
529e55b6	128	.fault = fb_deferred_io_fault,
60b59bea JK	129	.page_mkwrite = fb_deferred_io_mkwrite,
	130	};
	131
d847471d IC	132	static int fb_deferred_io_set_page_dirty(struct page *page)
	133	{
	134	if (!PageDirty(page))
	135	SetPageDirty(page);
	136	return 0;
	137	}
	138
	139	static const struct address_space_operations fb_deferred_io_aops = {
	140	.set_page_dirty = fb_deferred_io_set_page_dirty,
	141	};
	142
60b59bea JK	143	static int fb_deferred_io_mmap(struct fb_info info, struct vm_area_struct vma)
	144	{
	145	vma->vm_ops = &fb_deferred_io_vm_ops;
7164bb43 KRW	146	vma->vm_flags \|= ( VM_RESERVED \| VM_DONTEXPAND );
	147	if (!(info->flags & FBINFO_VIRTFB))
	148	vma->vm_flags \|= VM_IO;
60b59bea JK	149	vma->vm_private_data = info;
	150	return 0;
	151	}
	152
	153	/* workqueue callback */
	154	static void fb_deferred_io_work(struct work_struct *work)
	155	{
	156	struct fb_info *info = container_of(work, struct fb_info,
	157	deferred_work.work);
60b59bea	158	struct fb_deferred_io *fbdefio = info->fbdefio;
49bbd815 AH	159	struct page page, tmp_page;
	160	struct list_head node, tmp_node;
	161	struct list_head non_dirty;
	162
	163	INIT_LIST_HEAD(&non_dirty);
60b59bea JK	164
	165	/* here we mkclean the pages, then do all deferred IO */
	166	mutex_lock(&fbdefio->lock);
49bbd815 AH	167	list_for_each_entry_safe(page, tmp_page, &fbdefio->pagelist, lru) {
	168	lock_page(page);
	169	/*
	170	* The workqueue callback can be triggered after a
	171	* ->page_mkwrite() call but before the PTE has been marked
	172	* dirty. In this case page_mkclean() won't "rearm" the page.
	173	*
	174	* To avoid this, remove those "non-dirty" pages from the
	175	* pagelist before calling the driver's callback, then add
	176	* them back to get processed on the next work iteration.
	177	* At that time, their PTEs will hopefully be dirty for real.
	178	*/
	179	if (!page_mkclean(page))
	180	list_move_tail(&page->lru, &non_dirty);
	181	unlock_page(page);
60b59bea JK	182	}
	183
	184	/* driver's callback with pagelist */
	185	fbdefio->deferred_io(info, &fbdefio->pagelist);
	186
49bbd815 AH	187	/* clear the list... */
49bbd815 AH	188	list_for_each_safe(node, tmp_node, &fbdefio->pagelist) {
60b59bea JK	189	list_del(node);
60b59bea JK	190	}
49bbd815 AH	191	/* ... and add back the "non-dirty" pages to the list */
49bbd815 AH	192	list_splice_tail(&non_dirty, &fbdefio->pagelist);
60b59bea JK	193	mutex_unlock(&fbdefio->lock);
	194	}
	195
	196	void fb_deferred_io_init(struct fb_info *info)
	197	{
	198	struct fb_deferred_io *fbdefio = info->fbdefio;
	199
	200	BUG_ON(!fbdefio);
	201	mutex_init(&fbdefio->lock);
	202	info->fbops->fb_mmap = fb_deferred_io_mmap;
	203	INIT_DELAYED_WORK(&info->deferred_work, fb_deferred_io_work);
	204	INIT_LIST_HEAD(&fbdefio->pagelist);
	205	if (fbdefio->delay == 0) /* set a default of 1 s */
	206	fbdefio->delay = HZ;
	207	}
	208	EXPORT_SYMBOL_GPL(fb_deferred_io_init);
	209
d847471d IC	210	void fb_deferred_io_open(struct fb_info *info,
	211	struct inode *inode,
	212	struct file *file)
	213	{
	214	file->f_mapping->a_ops = &fb_deferred_io_aops;
	215	}
	216	EXPORT_SYMBOL_GPL(fb_deferred_io_open);
	217
60b59bea JK	218	void fb_deferred_io_cleanup(struct fb_info *info)
	219	{
	220	struct fb_deferred_io *fbdefio = info->fbdefio;
49bbd815	221	struct list_head node, tmp_node;
de7c6d15 JK	222	struct page *page;
de7c6d15 JK	223	int i;
60b59bea JK	224
	225	BUG_ON(!fbdefio);
	226	cancel_delayed_work(&info->deferred_work);
	227	flush_scheduled_work();
de7c6d15	228
49bbd815 AH	229	/* the list may have still some non-dirty pages at this point */
	230	mutex_lock(&fbdefio->lock);
	231	list_for_each_safe(node, tmp_node, &fbdefio->pagelist) {
	232	list_del(node);
	233	}
	234	mutex_unlock(&fbdefio->lock);
	235
de7c6d15 JK	236	/* clear out the mapping that we setup */
de7c6d15 JK	237	for (i = 0 ; i < info->fix.smem_len; i += PAGE_SIZE) {
37b48379	238	page = fb_deferred_io_page(info, i);
de7c6d15 JK	239	page->mapping = NULL;
de7c6d15 JK	240	}
6e1038a9 MD	241
	242	info->fbops->fb_mmap = NULL;
	243	mutex_destroy(&fbdefio->lock);
60b59bea JK	244	}
	245	EXPORT_SYMBOL_GPL(fb_deferred_io_cleanup);
	246
	247	MODULE_LICENSE("GPL");