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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 | |
7 | * License. See the file COPYING in the main directory of this archive | |
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> | |
22 | #include <asm/uaccess.h> | |
23 | ||
24 | /* to support deferred IO */ | |
25 | #include <linux/rmap.h> | |
26 | #include <linux/pagemap.h> | |
27 | ||
28 | /* this is to find and return the vmalloc-ed fb pages */ | |
29 | static struct page* fb_deferred_io_nopage(struct vm_area_struct *vma, | |
30 | unsigned long vaddr, int *type) | |
31 | { | |
32 | unsigned long offset; | |
33 | struct page *page; | |
34 | struct fb_info *info = vma->vm_private_data; | |
35 | ||
36 | offset = (vaddr - vma->vm_start) + (vma->vm_pgoff << PAGE_SHIFT); | |
37 | if (offset >= info->fix.smem_len) | |
38 | return NOPAGE_SIGBUS; | |
39 | ||
40 | page = vmalloc_to_page(info->screen_base + offset); | |
41 | if (!page) | |
42 | return NOPAGE_OOM; | |
43 | ||
44 | get_page(page); | |
45 | if (type) | |
46 | *type = VM_FAULT_MINOR; | |
47 | return page; | |
48 | } | |
49 | ||
5e841b88 PM |
50 | int fb_deferred_io_fsync(struct file *file, struct dentry *dentry, int datasync) |
51 | { | |
52 | struct fb_info *info = file->private_data; | |
53 | ||
54 | /* Kill off the delayed work */ | |
55 | cancel_rearming_delayed_work(&info->deferred_work); | |
56 | ||
57 | /* Run it immediately */ | |
58 | return schedule_delayed_work(&info->deferred_work, 0); | |
59 | } | |
60 | EXPORT_SYMBOL_GPL(fb_deferred_io_fsync); | |
61 | ||
60b59bea | 62 | /* vm_ops->page_mkwrite handler */ |
7bf1ea33 AB |
63 | static int fb_deferred_io_mkwrite(struct vm_area_struct *vma, |
64 | struct page *page) | |
60b59bea JK |
65 | { |
66 | struct fb_info *info = vma->vm_private_data; | |
67 | struct fb_deferred_io *fbdefio = info->fbdefio; | |
68 | ||
69 | /* this is a callback we get when userspace first tries to | |
70 | write to the page. we schedule a workqueue. that workqueue | |
71 | will eventually mkclean the touched pages and execute the | |
72 | deferred framebuffer IO. then if userspace touches a page | |
73 | again, we repeat the same scheme */ | |
74 | ||
75 | /* protect against the workqueue changing the page list */ | |
76 | mutex_lock(&fbdefio->lock); | |
77 | list_add(&page->lru, &fbdefio->pagelist); | |
78 | mutex_unlock(&fbdefio->lock); | |
79 | ||
80 | /* come back after delay to process the deferred IO */ | |
81 | schedule_delayed_work(&info->deferred_work, fbdefio->delay); | |
82 | return 0; | |
83 | } | |
84 | ||
85 | static struct vm_operations_struct fb_deferred_io_vm_ops = { | |
86 | .nopage = fb_deferred_io_nopage, | |
87 | .page_mkwrite = fb_deferred_io_mkwrite, | |
88 | }; | |
89 | ||
90 | static int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma) | |
91 | { | |
92 | vma->vm_ops = &fb_deferred_io_vm_ops; | |
93 | vma->vm_flags |= ( VM_IO | VM_RESERVED | VM_DONTEXPAND ); | |
94 | vma->vm_private_data = info; | |
95 | return 0; | |
96 | } | |
97 | ||
98 | /* workqueue callback */ | |
99 | static void fb_deferred_io_work(struct work_struct *work) | |
100 | { | |
101 | struct fb_info *info = container_of(work, struct fb_info, | |
102 | deferred_work.work); | |
103 | struct list_head *node, *next; | |
104 | struct page *cur; | |
105 | struct fb_deferred_io *fbdefio = info->fbdefio; | |
106 | ||
107 | /* here we mkclean the pages, then do all deferred IO */ | |
108 | mutex_lock(&fbdefio->lock); | |
109 | list_for_each_entry(cur, &fbdefio->pagelist, lru) { | |
110 | lock_page(cur); | |
111 | page_mkclean(cur); | |
112 | unlock_page(cur); | |
113 | } | |
114 | ||
115 | /* driver's callback with pagelist */ | |
116 | fbdefio->deferred_io(info, &fbdefio->pagelist); | |
117 | ||
118 | /* clear the list */ | |
119 | list_for_each_safe(node, next, &fbdefio->pagelist) { | |
120 | list_del(node); | |
121 | } | |
122 | mutex_unlock(&fbdefio->lock); | |
123 | } | |
124 | ||
125 | void fb_deferred_io_init(struct fb_info *info) | |
126 | { | |
127 | struct fb_deferred_io *fbdefio = info->fbdefio; | |
128 | ||
129 | BUG_ON(!fbdefio); | |
130 | mutex_init(&fbdefio->lock); | |
131 | info->fbops->fb_mmap = fb_deferred_io_mmap; | |
132 | INIT_DELAYED_WORK(&info->deferred_work, fb_deferred_io_work); | |
133 | INIT_LIST_HEAD(&fbdefio->pagelist); | |
134 | if (fbdefio->delay == 0) /* set a default of 1 s */ | |
135 | fbdefio->delay = HZ; | |
136 | } | |
137 | EXPORT_SYMBOL_GPL(fb_deferred_io_init); | |
138 | ||
139 | void fb_deferred_io_cleanup(struct fb_info *info) | |
140 | { | |
141 | struct fb_deferred_io *fbdefio = info->fbdefio; | |
142 | ||
143 | BUG_ON(!fbdefio); | |
144 | cancel_delayed_work(&info->deferred_work); | |
145 | flush_scheduled_work(); | |
146 | } | |
147 | EXPORT_SYMBOL_GPL(fb_deferred_io_cleanup); | |
148 | ||
149 | MODULE_LICENSE("GPL"); |