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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> | |
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, |
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 | |
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; |
66 | return 0; | |
60b59bea JK |
67 | } |
68 | ||
02c24a82 | 69 | int fb_deferred_io_fsync(struct file *file, loff_t start, loff_t end, int datasync) |
5e841b88 PM |
70 | { |
71 | struct fb_info *info = file->private_data; | |
02c24a82 JB |
72 | struct inode *inode = file->f_path.dentry->d_inode; |
73 | int err = filemap_write_and_wait_range(inode->i_mapping, start, end); | |
74 | if (err) | |
75 | return err; | |
5e841b88 | 76 | |
94e2bd68 | 77 | /* Skip if deferred io is compiled-in but disabled on this fbdev */ |
87884bd8 MD |
78 | if (!info->fbdefio) |
79 | return 0; | |
80 | ||
02c24a82 | 81 | mutex_lock(&inode->i_mutex); |
5e841b88 | 82 | /* Kill off the delayed work */ |
afe2c511 | 83 | cancel_delayed_work_sync(&info->deferred_work); |
5e841b88 PM |
84 | |
85 | /* Run it immediately */ | |
02c24a82 JB |
86 | err = schedule_delayed_work(&info->deferred_work, 0); |
87 | mutex_unlock(&inode->i_mutex); | |
88 | return err; | |
5e841b88 PM |
89 | } |
90 | EXPORT_SYMBOL_GPL(fb_deferred_io_fsync); | |
91 | ||
60b59bea | 92 | /* vm_ops->page_mkwrite handler */ |
7bf1ea33 | 93 | static int fb_deferred_io_mkwrite(struct vm_area_struct *vma, |
c2ec175c | 94 | struct vm_fault *vmf) |
60b59bea | 95 | { |
c2ec175c | 96 | struct page *page = vmf->page; |
60b59bea JK |
97 | struct fb_info *info = vma->vm_private_data; |
98 | struct fb_deferred_io *fbdefio = info->fbdefio; | |
f31ad92f | 99 | struct page *cur; |
60b59bea JK |
100 | |
101 | /* this is a callback we get when userspace first tries to | |
102 | write to the page. we schedule a workqueue. that workqueue | |
103 | will eventually mkclean the touched pages and execute the | |
104 | deferred framebuffer IO. then if userspace touches a page | |
105 | again, we repeat the same scheme */ | |
106 | ||
107 | /* protect against the workqueue changing the page list */ | |
108 | mutex_lock(&fbdefio->lock); | |
f31ad92f | 109 | |
d6d03f91 AH |
110 | /* |
111 | * We want the page to remain locked from ->page_mkwrite until | |
112 | * the PTE is marked dirty to avoid page_mkclean() being called | |
113 | * before the PTE is updated, which would leave the page ignored | |
114 | * by defio. | |
115 | * Do this by locking the page here and informing the caller | |
116 | * about it with VM_FAULT_LOCKED. | |
117 | */ | |
118 | lock_page(page); | |
119 | ||
f31ad92f JK |
120 | /* we loop through the pagelist before adding in order |
121 | to keep the pagelist sorted */ | |
122 | list_for_each_entry(cur, &fbdefio->pagelist, lru) { | |
123 | /* this check is to catch the case where a new | |
124 | process could start writing to the same page | |
125 | through a new pte. this new access can cause the | |
126 | mkwrite even when the original ps's pte is marked | |
127 | writable */ | |
128 | if (unlikely(cur == page)) | |
129 | goto page_already_added; | |
130 | else if (cur->index > page->index) | |
131 | break; | |
132 | } | |
133 | ||
134 | list_add_tail(&page->lru, &cur->lru); | |
135 | ||
136 | page_already_added: | |
60b59bea JK |
137 | mutex_unlock(&fbdefio->lock); |
138 | ||
139 | /* come back after delay to process the deferred IO */ | |
140 | schedule_delayed_work(&info->deferred_work, fbdefio->delay); | |
d6d03f91 | 141 | return VM_FAULT_LOCKED; |
60b59bea JK |
142 | } |
143 | ||
f0f37e2f | 144 | static const struct vm_operations_struct fb_deferred_io_vm_ops = { |
529e55b6 | 145 | .fault = fb_deferred_io_fault, |
60b59bea JK |
146 | .page_mkwrite = fb_deferred_io_mkwrite, |
147 | }; | |
148 | ||
d847471d IC |
149 | static int fb_deferred_io_set_page_dirty(struct page *page) |
150 | { | |
151 | if (!PageDirty(page)) | |
152 | SetPageDirty(page); | |
153 | return 0; | |
154 | } | |
155 | ||
156 | static const struct address_space_operations fb_deferred_io_aops = { | |
157 | .set_page_dirty = fb_deferred_io_set_page_dirty, | |
158 | }; | |
159 | ||
60b59bea JK |
160 | static int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma) |
161 | { | |
162 | vma->vm_ops = &fb_deferred_io_vm_ops; | |
7164bb43 KRW |
163 | vma->vm_flags |= ( VM_RESERVED | VM_DONTEXPAND ); |
164 | if (!(info->flags & FBINFO_VIRTFB)) | |
165 | vma->vm_flags |= VM_IO; | |
60b59bea JK |
166 | vma->vm_private_data = info; |
167 | return 0; | |
168 | } | |
169 | ||
170 | /* workqueue callback */ | |
171 | static void fb_deferred_io_work(struct work_struct *work) | |
172 | { | |
173 | struct fb_info *info = container_of(work, struct fb_info, | |
174 | deferred_work.work); | |
3f505ca4 AH |
175 | struct list_head *node, *next; |
176 | struct page *cur; | |
60b59bea JK |
177 | struct fb_deferred_io *fbdefio = info->fbdefio; |
178 | ||
179 | /* here we mkclean the pages, then do all deferred IO */ | |
180 | mutex_lock(&fbdefio->lock); | |
3f505ca4 AH |
181 | list_for_each_entry(cur, &fbdefio->pagelist, lru) { |
182 | lock_page(cur); | |
183 | page_mkclean(cur); | |
184 | unlock_page(cur); | |
60b59bea JK |
185 | } |
186 | ||
187 | /* driver's callback with pagelist */ | |
188 | fbdefio->deferred_io(info, &fbdefio->pagelist); | |
189 | ||
3f505ca4 AH |
190 | /* clear the list */ |
191 | list_for_each_safe(node, next, &fbdefio->pagelist) { | |
60b59bea JK |
192 | list_del(node); |
193 | } | |
194 | mutex_unlock(&fbdefio->lock); | |
195 | } | |
196 | ||
197 | void fb_deferred_io_init(struct fb_info *info) | |
198 | { | |
199 | struct fb_deferred_io *fbdefio = info->fbdefio; | |
200 | ||
201 | BUG_ON(!fbdefio); | |
202 | mutex_init(&fbdefio->lock); | |
203 | info->fbops->fb_mmap = fb_deferred_io_mmap; | |
204 | INIT_DELAYED_WORK(&info->deferred_work, fb_deferred_io_work); | |
205 | INIT_LIST_HEAD(&fbdefio->pagelist); | |
206 | if (fbdefio->delay == 0) /* set a default of 1 s */ | |
207 | fbdefio->delay = HZ; | |
208 | } | |
209 | EXPORT_SYMBOL_GPL(fb_deferred_io_init); | |
210 | ||
d847471d IC |
211 | void fb_deferred_io_open(struct fb_info *info, |
212 | struct inode *inode, | |
213 | struct file *file) | |
214 | { | |
215 | file->f_mapping->a_ops = &fb_deferred_io_aops; | |
216 | } | |
217 | EXPORT_SYMBOL_GPL(fb_deferred_io_open); | |
218 | ||
60b59bea JK |
219 | void fb_deferred_io_cleanup(struct fb_info *info) |
220 | { | |
221 | struct fb_deferred_io *fbdefio = info->fbdefio; | |
de7c6d15 JK |
222 | struct page *page; |
223 | int i; | |
60b59bea JK |
224 | |
225 | BUG_ON(!fbdefio); | |
181b74ef | 226 | cancel_delayed_work_sync(&info->deferred_work); |
de7c6d15 JK |
227 | |
228 | /* clear out the mapping that we setup */ | |
229 | for (i = 0 ; i < info->fix.smem_len; i += PAGE_SIZE) { | |
37b48379 | 230 | page = fb_deferred_io_page(info, i); |
de7c6d15 JK |
231 | page->mapping = NULL; |
232 | } | |
6e1038a9 MD |
233 | |
234 | info->fbops->fb_mmap = NULL; | |
235 | mutex_destroy(&fbdefio->lock); | |
60b59bea JK |
236 | } |
237 | EXPORT_SYMBOL_GPL(fb_deferred_io_cleanup); | |
238 | ||
239 | MODULE_LICENSE("GPL"); |