[linux-block.git] / drivers / video / fbdev / core / 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>

static struct page *fb_deferred_io_get_page(struct fb_info *info, unsigned long offs)
{
	struct fb_deferred_io *fbdefio = info->fbdefio;
	const void *screen_buffer = info->screen_buffer;
	struct page *page = NULL;

	if (fbdefio->get_page)
		return fbdefio->get_page(info, offs);

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

	if (page)
		get_page(page);

	return page;
}

static struct fb_deferred_io_pageref *fb_deferred_io_pageref_lookup(struct fb_info *info,
								    unsigned long offset,
								    struct page *page)
{
	unsigned long pgoff = offset >> PAGE_SHIFT;
	struct fb_deferred_io_pageref *pageref;

	if (fb_WARN_ON_ONCE(info, pgoff >= info->npagerefs))
		return NULL; /* incorrect allocation size */

	/* 1:1 mapping between pageref and page offset */
	pageref = &info->pagerefs[pgoff];

	if (pageref->page)
		goto out;

	pageref->page = page;
	pageref->offset = pgoff << PAGE_SHIFT;
	INIT_LIST_HEAD(&pageref->list);

out:
	if (fb_WARN_ON_ONCE(info, pageref->page != page))
		return NULL; /* inconsistent state */
	return pageref;
}

static void fb_deferred_io_pageref_clear(struct fb_deferred_io_pageref *pageref)
{
	struct page *page = pageref->page;

	if (page)
		page->mapping = NULL;
}

static struct fb_deferred_io_pageref *fb_deferred_io_pageref_get(struct fb_info *info,
								 unsigned long offset,
								 struct page *page)
{
	struct fb_deferred_io *fbdefio = info->fbdefio;
	struct list_head *pos = &fbdefio->pagereflist;
	struct fb_deferred_io_pageref *pageref, *cur;

	pageref = fb_deferred_io_pageref_lookup(info, offset, page);
	if (!pageref)
		return NULL;

	/*
	 * 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 a call to .page_mkwrite even if the original process'
	 * PTE is marked writable.
	 */
	if (!list_empty(&pageref->list))
		goto pageref_already_added;

	if (unlikely(fbdefio->sort_pagereflist)) {
		/*
		 * We loop through the list of pagerefs before adding in
		 * order to keep the pagerefs sorted. This has significant
		 * overhead of O(n^2) with n being the number of written
		 * pages. If possible, drivers should try to work with
		 * unsorted page lists instead.
		 */
		list_for_each_entry(cur, &fbdefio->pagereflist, list) {
			if (cur->offset > pageref->offset)
				break;
		}
		pos = &cur->list;
	}

	list_add_tail(&pageref->list, pos);

pageref_already_added:
	return pageref;
}

static void fb_deferred_io_pageref_put(struct fb_deferred_io_pageref *pageref,
				       struct fb_info *info)
{
	list_del_init(&pageref->list);
}

/* this is to find and return the vmalloc-ed fb pages */
static vm_fault_t fb_deferred_io_fault(struct vm_fault *vmf)
{
	unsigned long offset;
	struct page *page;
	struct fb_info *info = vmf->vma->vm_private_data;

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

	page = fb_deferred_io_get_page(info, offset);
	if (!page)
		return VM_FAULT_SIGBUS;

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

	BUG_ON(!page->mapping);
	page->index = vmf->pgoff; /* for folio_mkclean() */

	vmf->page = page;
	return 0;
}

int fb_deferred_io_fsync(struct file *file, loff_t start, loff_t end, int datasync)
{
	struct fb_info *info = file->private_data;
	struct inode *inode = file_inode(file);
	int err = file_write_and_wait_range(file, start, end);
	if (err)
		return err;

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

	inode_lock(inode);
	flush_delayed_work(&info->deferred_work);
	inode_unlock(inode);

	return 0;
}
EXPORT_SYMBOL_GPL(fb_deferred_io_fsync);

/*
 * Adds a page to the dirty list. Call this from struct
 * vm_operations_struct.page_mkwrite.
 */
static vm_fault_t fb_deferred_io_track_page(struct fb_info *info, unsigned long offset,
					    struct page *page)
{
	struct fb_deferred_io *fbdefio = info->fbdefio;
	struct fb_deferred_io_pageref *pageref;
	vm_fault_t ret;

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

	pageref = fb_deferred_io_pageref_get(info, offset, page);
	if (WARN_ON_ONCE(!pageref)) {
		ret = VM_FAULT_OOM;
		goto err_mutex_unlock;
	}

	/*
	 * We want the page to remain locked from ->page_mkwrite until
	 * the PTE is marked dirty to avoid folio_mkclean() being called
	 * before the PTE is updated, which would leave the page ignored
	 * by defio.
	 * Do this by locking the page here and informing the caller
	 * about it with VM_FAULT_LOCKED.
	 */
	lock_page(pageref->page);

	mutex_unlock(&fbdefio->lock);

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

err_mutex_unlock:
	mutex_unlock(&fbdefio->lock);
	return ret;
}

/*
 * fb_deferred_io_page_mkwrite - Mark a page as written for deferred I/O
 * @fb_info: The fbdev info structure
 * @vmf: The VM fault
 *
 * 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.
 *
 * Returns:
 * VM_FAULT_LOCKED on success, or a VM_FAULT error otherwise.
 */
static vm_fault_t fb_deferred_io_page_mkwrite(struct fb_info *info, struct vm_fault *vmf)
{
	unsigned long offset = vmf->pgoff << PAGE_SHIFT;
	struct page *page = vmf->page;

	file_update_time(vmf->vma->vm_file);

	return fb_deferred_io_track_page(info, offset, page);
}

/* vm_ops->page_mkwrite handler */
static vm_fault_t fb_deferred_io_mkwrite(struct vm_fault *vmf)
{
	struct fb_info *info = vmf->vma->vm_private_data;

	return fb_deferred_io_page_mkwrite(info, vmf);
}

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

static const struct address_space_operations fb_deferred_io_aops = {
	.dirty_folio	= noop_dirty_folio,
};

int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma)
{
	vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);

	vma->vm_ops = &fb_deferred_io_vm_ops;
	vm_flags_set(vma, VM_DONTEXPAND | VM_DONTDUMP);
	if (!(info->flags & FBINFO_VIRTFB))
		vm_flags_set(vma, VM_IO);
	vma->vm_private_data = info;
	return 0;
}
EXPORT_SYMBOL_GPL(fb_deferred_io_mmap);

/* 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_pageref *pageref, *next;
	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(pageref, &fbdefio->pagereflist, list) {
		struct folio *folio = page_folio(pageref->page);

		folio_lock(folio);
		folio_mkclean(folio);
		folio_unlock(folio);
	}

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

	/* clear the list */
	list_for_each_entry_safe(pageref, next, &fbdefio->pagereflist, list)
		fb_deferred_io_pageref_put(pageref, info);

	mutex_unlock(&fbdefio->lock);
}

int fb_deferred_io_init(struct fb_info *info)
{
	struct fb_deferred_io *fbdefio = info->fbdefio;
	struct fb_deferred_io_pageref *pagerefs;
	unsigned long npagerefs;
	int ret;

	BUG_ON(!fbdefio);

	if (WARN_ON(!info->fix.smem_len))
		return -EINVAL;

	mutex_init(&fbdefio->lock);
	INIT_DELAYED_WORK(&info->deferred_work, fb_deferred_io_work);
	INIT_LIST_HEAD(&fbdefio->pagereflist);
	if (fbdefio->delay == 0) /* set a default of 1 s */
		fbdefio->delay = HZ;

	npagerefs = DIV_ROUND_UP(info->fix.smem_len, PAGE_SIZE);

	/* alloc a page ref for each page of the display memory */
	pagerefs = kvcalloc(npagerefs, sizeof(*pagerefs), GFP_KERNEL);
	if (!pagerefs) {
		ret = -ENOMEM;
		goto err;
	}
	info->npagerefs = npagerefs;
	info->pagerefs = pagerefs;

	return 0;

err:
	mutex_destroy(&fbdefio->lock);
	return ret;
}
EXPORT_SYMBOL_GPL(fb_deferred_io_init);

void fb_deferred_io_open(struct fb_info *info,
			 struct inode *inode,
			 struct file *file)
{
	struct fb_deferred_io *fbdefio = info->fbdefio;

	file->f_mapping->a_ops = &fb_deferred_io_aops;
	fbdefio->open_count++;
}
EXPORT_SYMBOL_GPL(fb_deferred_io_open);

static void fb_deferred_io_lastclose(struct fb_info *info)
{
	unsigned long i;

	flush_delayed_work(&info->deferred_work);

	/* clear out the mapping that we setup */
	for (i = 0; i < info->npagerefs; ++i)
		fb_deferred_io_pageref_clear(&info->pagerefs[i]);
}

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

	if (!--fbdefio->open_count)
		fb_deferred_io_lastclose(info);
}
EXPORT_SYMBOL_GPL(fb_deferred_io_release);

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

	fb_deferred_io_lastclose(info);

	kvfree(info->pagerefs);
	mutex_destroy(&fbdefio->lock);
}
EXPORT_SYMBOL_GPL(fb_deferred_io_cleanup);
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
1ecbc7dd	26	static struct page fb_deferred_io_get_page(struct fb_info info, unsigned long offs)
37b48379	27	{
747bda7b	28	struct fb_deferred_io *fbdefio = info->fbdefio;
abc79a0e	29	const void *screen_buffer = info->screen_buffer;
dcaefc82	30	struct page *page = NULL;
37b48379	31
747bda7b TZ	32	if (fbdefio->get_page)
	33	return fbdefio->get_page(info, offs);
	34
abc79a0e TZ	35	if (is_vmalloc_addr(screen_buffer + offs))
abc79a0e TZ	36	page = vmalloc_to_page(screen_buffer + offs);
dcaefc82	37	else if (info->fix.smem_start)
37b48379 MD	38	page = pfn_to_page((info->fix.smem_start + offs) >> PAGE_SHIFT);
37b48379 MD	39
1ecbc7dd TZ	40	if (page)
	41	get_page(page);
	42
37b48379 MD	43	return page;
	44	}
	45
757a2713 TZ	46	static struct fb_deferred_io_pageref fb_deferred_io_pageref_lookup(struct fb_info info,
	47	unsigned long offset,
	48	struct page *page)
	49	{
	50	unsigned long pgoff = offset >> PAGE_SHIFT;
	51	struct fb_deferred_io_pageref *pageref;
	52
	53	if (fb_WARN_ON_ONCE(info, pgoff >= info->npagerefs))
	54	return NULL; /* incorrect allocation size */
	55
	56	/* 1:1 mapping between pageref and page offset */
	57	pageref = &info->pagerefs[pgoff];
	58
	59	if (pageref->page)
	60	goto out;
	61
	62	pageref->page = page;
	63	pageref->offset = pgoff << PAGE_SHIFT;
	64	INIT_LIST_HEAD(&pageref->list);
	65
	66	out:
	67	if (fb_WARN_ON_ONCE(info, pageref->page != page))
	68	return NULL; /* inconsistent state */
	69	return pageref;
	70	}
	71
28aea43c TZ	72	static void fb_deferred_io_pageref_clear(struct fb_deferred_io_pageref *pageref)
	73	{
	74	struct page *page = pageref->page;
	75
	76	if (page)
	77	page->mapping = NULL;
	78	}
	79
56c134f7 TZ	80	static struct fb_deferred_io_pageref fb_deferred_io_pageref_get(struct fb_info info,
	81	unsigned long offset,
	82	struct page *page)
	83	{
	84	struct fb_deferred_io *fbdefio = info->fbdefio;
e80eec1b	85	struct list_head *pos = &fbdefio->pagereflist;
56c134f7 TZ	86	struct fb_deferred_io_pageref pageref, cur;
56c134f7 TZ	87
757a2713 TZ	88	pageref = fb_deferred_io_pageref_lookup(info, offset, page);
	89	if (!pageref)
	90	return NULL;
56c134f7 TZ	91
	92	/*
	93	* This check is to catch the case where a new process could start
	94	* writing to the same page through a new PTE. This new access
	95	* can cause a call to .page_mkwrite even if the original process'
	96	* PTE is marked writable.
	97	*/
	98	if (!list_empty(&pageref->list))
	99	goto pageref_already_added;
	100
e80eec1b	101	if (unlikely(fbdefio->sort_pagereflist)) {
56c134f7 TZ	102	/*
	103	* We loop through the list of pagerefs before adding in
	104	* order to keep the pagerefs sorted. This has significant
	105	* overhead of O(n^2) with n being the number of written
	106	* pages. If possible, drivers should try to work with
	107	* unsorted page lists instead.
	108	*/
e80eec1b	109	list_for_each_entry(cur, &fbdefio->pagereflist, list) {
56c134f7 TZ	110	if (cur->offset > pageref->offset)
	111	break;
	112	}
	113	pos = &cur->list;
	114	}
	115
	116	list_add_tail(&pageref->list, pos);
	117
	118	pageref_already_added:
	119	return pageref;
	120	}
	121
	122	static void fb_deferred_io_pageref_put(struct fb_deferred_io_pageref *pageref,
	123	struct fb_info *info)
	124	{
	125	list_del_init(&pageref->list);
	126	}
	127
60b59bea	128	/* this is to find and return the vmalloc-ed fb pages */
c8b54776	129	static vm_fault_t fb_deferred_io_fault(struct vm_fault *vmf)
60b59bea JK	130	{
	131	unsigned long offset;
	132	struct page *page;
11bac800	133	struct fb_info *info = vmf->vma->vm_private_data;
60b59bea	134
529e55b6	135	offset = vmf->pgoff << PAGE_SHIFT;
60b59bea	136	if (offset >= info->fix.smem_len)
529e55b6	137	return VM_FAULT_SIGBUS;
60b59bea	138
1ecbc7dd	139	page = fb_deferred_io_get_page(info, offset);
60b59bea	140	if (!page)
529e55b6	141	return VM_FAULT_SIGBUS;
60b59bea	142
0b78f8bc MW	143	if (vmf->vma->vm_file)
	144	page->mapping = vmf->vma->vm_file->f_mapping;
	145	else
	146	printk(KERN_ERR "no mapping available\n");
	147
	148	BUG_ON(!page->mapping);
a929e0d1	149	page->index = vmf->pgoff; /* for folio_mkclean() */
de7c6d15	150
529e55b6 NP	151	vmf->page = page;
529e55b6 NP	152	return 0;
60b59bea JK	153	}
60b59bea JK	154
02c24a82	155	int fb_deferred_io_fsync(struct file *file, loff_t start, loff_t end, int datasync)
5e841b88 PM	156	{
5e841b88 PM	157	struct fb_info *info = file->private_data;
496ad9aa	158	struct inode *inode = file_inode(file);
3b49c9a1	159	int err = file_write_and_wait_range(file, start, end);
02c24a82 JB	160	if (err)
02c24a82 JB	161	return err;
5e841b88	162
94e2bd68	163	/* Skip if deferred io is compiled-in but disabled on this fbdev */
87884bd8 MD	164	if (!info->fbdefio)
	165	return 0;
	166
5955102c	167	inode_lock(inode);
15e4c1f4	168	flush_delayed_work(&info->deferred_work);
5955102c	169	inode_unlock(inode);
30ea9c52 TV	170
30ea9c52 TV	171	return 0;
5e841b88 PM	172	}
	173	EXPORT_SYMBOL_GPL(fb_deferred_io_fsync);
	174
3ed38112 TZ	175	/*
	176	* Adds a page to the dirty list. Call this from struct
	177	* vm_operations_struct.page_mkwrite.
	178	*/
	179	static vm_fault_t fb_deferred_io_track_page(struct fb_info *info, unsigned long offset,
	180	struct page *page)
60b59bea	181	{
60b59bea	182	struct fb_deferred_io *fbdefio = info->fbdefio;
56c134f7	183	struct fb_deferred_io_pageref *pageref;
56c134f7 TZ	184	vm_fault_t ret;
56c134f7 TZ	185
60b59bea JK	186	/* protect against the workqueue changing the page list */
60b59bea JK	187	mutex_lock(&fbdefio->lock);
f31ad92f	188
56c134f7 TZ	189	pageref = fb_deferred_io_pageref_get(info, offset, page);
	190	if (WARN_ON_ONCE(!pageref)) {
	191	ret = VM_FAULT_OOM;
	192	goto err_mutex_unlock;
	193	}
	194
d6d03f91 AH	195	/*
d6d03f91 AH	196	* We want the page to remain locked from ->page_mkwrite until
a929e0d1	197	* the PTE is marked dirty to avoid folio_mkclean() being called
d6d03f91 AH	198	* before the PTE is updated, which would leave the page ignored
	199	* by defio.
	200	* Do this by locking the page here and informing the caller
	201	* about it with VM_FAULT_LOCKED.
	202	*/
56c134f7	203	lock_page(pageref->page);
f31ad92f	204
60b59bea JK	205	mutex_unlock(&fbdefio->lock);
	206
	207	/* come back after delay to process the deferred IO */
	208	schedule_delayed_work(&info->deferred_work, fbdefio->delay);
d6d03f91	209	return VM_FAULT_LOCKED;
56c134f7 TZ	210
	211	err_mutex_unlock:
	212	mutex_unlock(&fbdefio->lock);
	213	return ret;
60b59bea JK	214	}
60b59bea JK	215
3ed38112 TZ	216	/*
	217	* fb_deferred_io_page_mkwrite - Mark a page as written for deferred I/O
	218	* @fb_info: The fbdev info structure
	219	* @vmf: The VM fault
	220	*
	221	* This is a callback we get when userspace first tries to
	222	* write to the page. We schedule a workqueue. That workqueue
	223	* will eventually mkclean the touched pages and execute the
	224	* deferred framebuffer IO. Then if userspace touches a page
	225	* again, we repeat the same scheme.
	226	*
	227	* Returns:
	228	* VM_FAULT_LOCKED on success, or a VM_FAULT error otherwise.
	229	*/
	230	static vm_fault_t fb_deferred_io_page_mkwrite(struct fb_info info, struct vm_fault vmf)
	231	{
78d9161d	232	unsigned long offset = vmf->pgoff << PAGE_SHIFT;
3ed38112 TZ	233	struct page *page = vmf->page;
	234
	235	file_update_time(vmf->vma->vm_file);
	236
	237	return fb_deferred_io_track_page(info, offset, page);
	238	}
	239
	240	/* vm_ops->page_mkwrite handler */
	241	static vm_fault_t fb_deferred_io_mkwrite(struct vm_fault *vmf)
	242	{
	243	struct fb_info *info = vmf->vma->vm_private_data;
	244
	245	return fb_deferred_io_page_mkwrite(info, vmf);
	246	}
	247
f0f37e2f	248	static const struct vm_operations_struct fb_deferred_io_vm_ops = {
529e55b6	249	.fault = fb_deferred_io_fault,
60b59bea JK	250	.page_mkwrite = fb_deferred_io_mkwrite,
	251	};
	252
0b78f8bc	253	static const struct address_space_operations fb_deferred_io_aops = {
51cdea7a	254	.dirty_folio = noop_dirty_folio,
0b78f8bc MW	255	};
0b78f8bc MW	256
ba026334	257	int fb_deferred_io_mmap(struct fb_info info, struct vm_area_struct vma)
60b59bea	258	{
76f92201 TZ	259	vma->vm_page_prot = pgprot_decrypted(vma->vm_page_prot);
76f92201 TZ	260
60b59bea	261	vma->vm_ops = &fb_deferred_io_vm_ops;
1c71222e	262	vm_flags_set(vma, VM_DONTEXPAND \| VM_DONTDUMP);
7164bb43	263	if (!(info->flags & FBINFO_VIRTFB))
1c71222e	264	vm_flags_set(vma, VM_IO);
60b59bea JK	265	vma->vm_private_data = info;
	266	return 0;
	267	}
59055851	268	EXPORT_SYMBOL_GPL(fb_deferred_io_mmap);
60b59bea JK	269
	270	/* workqueue callback */
	271	static void fb_deferred_io_work(struct work_struct *work)
	272	{
56c134f7 TZ	273	struct fb_info *info = container_of(work, struct fb_info, deferred_work.work);
56c134f7 TZ	274	struct fb_deferred_io_pageref pageref, next;
60b59bea JK	275	struct fb_deferred_io *fbdefio = info->fbdefio;
	276
	277	/* here we mkclean the pages, then do all deferred IO */
	278	mutex_lock(&fbdefio->lock);
e80eec1b	279	list_for_each_entry(pageref, &fbdefio->pagereflist, list) {
645b1399 KW	280	struct folio *folio = page_folio(pageref->page);
	281
	282	folio_lock(folio);
	283	folio_mkclean(folio);
	284	folio_unlock(folio);
60b59bea JK	285	}
60b59bea JK	286
e80eec1b TZ	287	/* driver's callback with pagereflist */
e80eec1b TZ	288	fbdefio->deferred_io(info, &fbdefio->pagereflist);
60b59bea	289
3f505ca4	290	/* clear the list */
e80eec1b	291	list_for_each_entry_safe(pageref, next, &fbdefio->pagereflist, list)
56c134f7 TZ	292	fb_deferred_io_pageref_put(pageref, info);
56c134f7 TZ	293
60b59bea JK	294	mutex_unlock(&fbdefio->lock);
	295	}
	296
56c134f7	297	int fb_deferred_io_init(struct fb_info *info)
60b59bea JK	298	{
60b59bea JK	299	struct fb_deferred_io *fbdefio = info->fbdefio;
56c134f7	300	struct fb_deferred_io_pageref *pagerefs;
757a2713	301	unsigned long npagerefs;
56c134f7	302	int ret;
60b59bea JK	303
60b59bea JK	304	BUG_ON(!fbdefio);
56c134f7 TZ	305
	306	if (WARN_ON(!info->fix.smem_len))
	307	return -EINVAL;
	308
60b59bea	309	mutex_init(&fbdefio->lock);
60b59bea	310	INIT_DELAYED_WORK(&info->deferred_work, fb_deferred_io_work);
e80eec1b	311	INIT_LIST_HEAD(&fbdefio->pagereflist);
60b59bea JK	312	if (fbdefio->delay == 0) /* set a default of 1 s */
60b59bea JK	313	fbdefio->delay = HZ;
856082f0	314
56c134f7 TZ	315	npagerefs = DIV_ROUND_UP(info->fix.smem_len, PAGE_SIZE);
	316
	317	/* alloc a page ref for each page of the display memory */
	318	pagerefs = kvcalloc(npagerefs, sizeof(*pagerefs), GFP_KERNEL);
	319	if (!pagerefs) {
	320	ret = -ENOMEM;
	321	goto err;
856082f0	322	}
56c134f7 TZ	323	info->npagerefs = npagerefs;
	324	info->pagerefs = pagerefs;
	325
	326	return 0;
	327
	328	err:
	329	mutex_destroy(&fbdefio->lock);
	330	return ret;
60b59bea JK	331	}
	332	EXPORT_SYMBOL_GPL(fb_deferred_io_init);
	333
0b78f8bc MW	334	void fb_deferred_io_open(struct fb_info *info,
	335	struct inode *inode,
	336	struct file *file)
	337	{
fe9ae05c TI	338	struct fb_deferred_io *fbdefio = info->fbdefio;
fe9ae05c TI	339
0b78f8bc	340	file->f_mapping->a_ops = &fb_deferred_io_aops;
fe9ae05c	341	fbdefio->open_count++;
0b78f8bc MW	342	}
	343	EXPORT_SYMBOL_GPL(fb_deferred_io_open);
	344
fe9ae05c	345	static void fb_deferred_io_lastclose(struct fb_info *info)
60b59bea	346	{
28aea43c	347	unsigned long i;
60b59bea	348
33cd6ea9	349	flush_delayed_work(&info->deferred_work);
0b78f8bc MW	350
0b78f8bc MW	351	/* clear out the mapping that we setup */
28aea43c TZ	352	for (i = 0; i < info->npagerefs; ++i)
28aea43c TZ	353	fb_deferred_io_pageref_clear(&info->pagerefs[i]);
3efc61d9	354	}
fe9ae05c TI	355
	356	void fb_deferred_io_release(struct fb_info *info)
	357	{
	358	struct fb_deferred_io *fbdefio = info->fbdefio;
	359
	360	if (!--fbdefio->open_count)
	361	fb_deferred_io_lastclose(info);
	362	}
3efc61d9 TI	363	EXPORT_SYMBOL_GPL(fb_deferred_io_release);
	364
	365	void fb_deferred_io_cleanup(struct fb_info *info)
	366	{
	367	struct fb_deferred_io *fbdefio = info->fbdefio;
	368
fe9ae05c	369	fb_deferred_io_lastclose(info);
0b78f8bc	370
56c134f7	371	kvfree(info->pagerefs);
6e1038a9	372	mutex_destroy(&fbdefio->lock);
60b59bea JK	373	}
60b59bea JK	374	EXPORT_SYMBOL_GPL(fb_deferred_io_cleanup);