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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 | |
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, |
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 | |
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; |
56 | return 0; | |
60b59bea JK |
57 | } |
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, |
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; |
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"); |