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path: root/drivers/video/fbdev/fb_defio.c
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Diffstat (limited to 'drivers/video/fbdev/fb_defio.c')
-rw-r--r--drivers/video/fbdev/fb_defio.c245
1 files changed, 245 insertions, 0 deletions
diff --git a/drivers/video/fbdev/fb_defio.c b/drivers/video/fbdev/fb_defio.c
new file mode 100644
index 000000000000..900aa4ecd617
--- /dev/null
+++ b/drivers/video/fbdev/fb_defio.c
@@ -0,0 +1,245 @@
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/vmalloc.h>
17#include <linux/delay.h>
18#include <linux/interrupt.h>
19#include <linux/fb.h>
20#include <linux/list.h>
21
22/* to support deferred IO */
23#include <linux/rmap.h>
24#include <linux/pagemap.h>
25
26static 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
39/* this is to find and return the vmalloc-ed fb pages */
40static int fb_deferred_io_fault(struct vm_area_struct *vma,
41 struct vm_fault *vmf)
42{
43 unsigned long offset;
44 struct page *page;
45 struct fb_info *info = vma->vm_private_data;
46
47 offset = vmf->pgoff << PAGE_SHIFT;
48 if (offset >= info->fix.smem_len)
49 return VM_FAULT_SIGBUS;
50
51 page = fb_deferred_io_page(info, offset);
52 if (!page)
53 return VM_FAULT_SIGBUS;
54
55 get_page(page);
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
65 vmf->page = page;
66 return 0;
67}
68
69int fb_deferred_io_fsync(struct file *file, loff_t start, loff_t end, int datasync)
70{
71 struct fb_info *info = file->private_data;
72 struct inode *inode = file_inode(file);
73 int err = filemap_write_and_wait_range(inode->i_mapping, start, end);
74 if (err)
75 return err;
76
77 /* Skip if deferred io is compiled-in but disabled on this fbdev */
78 if (!info->fbdefio)
79 return 0;
80
81 mutex_lock(&inode->i_mutex);
82 /* Kill off the delayed work */
83 cancel_delayed_work_sync(&info->deferred_work);
84
85 /* Run it immediately */
86 err = schedule_delayed_work(&info->deferred_work, 0);
87 mutex_unlock(&inode->i_mutex);
88 return err;
89}
90EXPORT_SYMBOL_GPL(fb_deferred_io_fsync);
91
92/* vm_ops->page_mkwrite handler */
93static int fb_deferred_io_mkwrite(struct vm_area_struct *vma,
94 struct vm_fault *vmf)
95{
96 struct page *page = vmf->page;
97 struct fb_info *info = vma->vm_private_data;
98 struct fb_deferred_io *fbdefio = info->fbdefio;
99 struct page *cur;
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 file_update_time(vma->vm_file);
108
109 /* protect against the workqueue changing the page list */
110 mutex_lock(&fbdefio->lock);
111
112 /* first write in this cycle, notify the driver */
113 if (fbdefio->first_io && list_empty(&fbdefio->pagelist))
114 fbdefio->first_io(info);
115
116 /*
117 * We want the page to remain locked from ->page_mkwrite until
118 * the PTE is marked dirty to avoid page_mkclean() being called
119 * before the PTE is updated, which would leave the page ignored
120 * by defio.
121 * Do this by locking the page here and informing the caller
122 * about it with VM_FAULT_LOCKED.
123 */
124 lock_page(page);
125
126 /* we loop through the pagelist before adding in order
127 to keep the pagelist sorted */
128 list_for_each_entry(cur, &fbdefio->pagelist, lru) {
129 /* this check is to catch the case where a new
130 process could start writing to the same page
131 through a new pte. this new access can cause the
132 mkwrite even when the original ps's pte is marked
133 writable */
134 if (unlikely(cur == page))
135 goto page_already_added;
136 else if (cur->index > page->index)
137 break;
138 }
139
140 list_add_tail(&page->lru, &cur->lru);
141
142page_already_added:
143 mutex_unlock(&fbdefio->lock);
144
145 /* come back after delay to process the deferred IO */
146 schedule_delayed_work(&info->deferred_work, fbdefio->delay);
147 return VM_FAULT_LOCKED;
148}
149
150static const struct vm_operations_struct fb_deferred_io_vm_ops = {
151 .fault = fb_deferred_io_fault,
152 .page_mkwrite = fb_deferred_io_mkwrite,
153};
154
155static int fb_deferred_io_set_page_dirty(struct page *page)
156{
157 if (!PageDirty(page))
158 SetPageDirty(page);
159 return 0;
160}
161
162static const struct address_space_operations fb_deferred_io_aops = {
163 .set_page_dirty = fb_deferred_io_set_page_dirty,
164};
165
166static int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma)
167{
168 vma->vm_ops = &fb_deferred_io_vm_ops;
169 vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
170 if (!(info->flags & FBINFO_VIRTFB))
171 vma->vm_flags |= VM_IO;
172 vma->vm_private_data = info;
173 return 0;
174}
175
176/* workqueue callback */
177static void fb_deferred_io_work(struct work_struct *work)
178{
179 struct fb_info *info = container_of(work, struct fb_info,
180 deferred_work.work);
181 struct list_head *node, *next;
182 struct page *cur;
183 struct fb_deferred_io *fbdefio = info->fbdefio;
184
185 /* here we mkclean the pages, then do all deferred IO */
186 mutex_lock(&fbdefio->lock);
187 list_for_each_entry(cur, &fbdefio->pagelist, lru) {
188 lock_page(cur);
189 page_mkclean(cur);
190 unlock_page(cur);
191 }
192
193 /* driver's callback with pagelist */
194 fbdefio->deferred_io(info, &fbdefio->pagelist);
195
196 /* clear the list */
197 list_for_each_safe(node, next, &fbdefio->pagelist) {
198 list_del(node);
199 }
200 mutex_unlock(&fbdefio->lock);
201}
202
203void fb_deferred_io_init(struct fb_info *info)
204{
205 struct fb_deferred_io *fbdefio = info->fbdefio;
206
207 BUG_ON(!fbdefio);
208 mutex_init(&fbdefio->lock);
209 info->fbops->fb_mmap = fb_deferred_io_mmap;
210 INIT_DELAYED_WORK(&info->deferred_work, fb_deferred_io_work);
211 INIT_LIST_HEAD(&fbdefio->pagelist);
212 if (fbdefio->delay == 0) /* set a default of 1 s */
213 fbdefio->delay = HZ;
214}
215EXPORT_SYMBOL_GPL(fb_deferred_io_init);
216
217void fb_deferred_io_open(struct fb_info *info,
218 struct inode *inode,
219 struct file *file)
220{
221 file->f_mapping->a_ops = &fb_deferred_io_aops;
222}
223EXPORT_SYMBOL_GPL(fb_deferred_io_open);
224
225void fb_deferred_io_cleanup(struct fb_info *info)
226{
227 struct fb_deferred_io *fbdefio = info->fbdefio;
228 struct page *page;
229 int i;
230
231 BUG_ON(!fbdefio);
232 cancel_delayed_work_sync(&info->deferred_work);
233
234 /* clear out the mapping that we setup */
235 for (i = 0 ; i < info->fix.smem_len; i += PAGE_SIZE) {
236 page = fb_deferred_io_page(info, i);
237 page->mapping = NULL;
238 }
239
240 info->fbops->fb_mmap = NULL;
241 mutex_destroy(&fbdefio->lock);
242}
243EXPORT_SYMBOL_GPL(fb_deferred_io_cleanup);
244
245MODULE_LICENSE("GPL");
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