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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 | ||
7ea80859 | 69 | int fb_deferred_io_fsync(struct file *file, int datasync) |
5e841b88 PM |
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; |
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... */ |
188 | list_for_each_safe(node, tmp_node, &fbdefio->pagelist) { | |
60b59bea JK |
189 | list_del(node); |
190 | } | |
49bbd815 AH |
191 | /* ... and add back the "non-dirty" pages to the list */ |
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; |
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 */ |
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; |
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"); |