Branch data Line data Source code
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 : : 26 : : static 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 */ 40 : 0 : static vm_fault_t fb_deferred_io_fault(struct vm_fault *vmf) 41 : : { 42 : 0 : unsigned long offset; 43 : 0 : struct page *page; 44 : 0 : struct fb_info *info = vmf->vma->vm_private_data; 45 : : 46 : 0 : offset = vmf->pgoff << PAGE_SHIFT; 47 [ # # ]: 0 : if (offset >= info->fix.smem_len) 48 : : return VM_FAULT_SIGBUS; 49 : : 50 : 0 : page = fb_deferred_io_page(info, offset); 51 [ # # ]: 0 : if (!page) 52 : : return VM_FAULT_SIGBUS; 53 : : 54 [ # # ]: 0 : get_page(page); 55 : : 56 [ # # ]: 0 : if (vmf->vma->vm_file) 57 : 0 : page->mapping = vmf->vma->vm_file->f_mapping; 58 : : else 59 : 0 : printk(KERN_ERR "no mapping available\n"); 60 : : 61 [ # # ]: 0 : BUG_ON(!page->mapping); 62 : 0 : page->index = vmf->pgoff; 63 : : 64 : 0 : vmf->page = page; 65 : 0 : return 0; 66 : : } 67 : : 68 : 0 : int fb_deferred_io_fsync(struct file *file, loff_t start, loff_t end, int datasync) 69 : : { 70 : 0 : struct fb_info *info = file->private_data; 71 : 0 : struct inode *inode = file_inode(file); 72 : 0 : int err = file_write_and_wait_range(file, start, end); 73 [ # # ]: 0 : if (err) 74 : : return err; 75 : : 76 : : /* Skip if deferred io is compiled-in but disabled on this fbdev */ 77 [ # # ]: 0 : if (!info->fbdefio) 78 : : return 0; 79 : : 80 : 0 : inode_lock(inode); 81 : : /* Kill off the delayed work */ 82 : 0 : cancel_delayed_work_sync(&info->deferred_work); 83 : : 84 : : /* Run it immediately */ 85 : 0 : schedule_delayed_work(&info->deferred_work, 0); 86 : 0 : inode_unlock(inode); 87 : : 88 : 0 : return 0; 89 : : } 90 : : EXPORT_SYMBOL_GPL(fb_deferred_io_fsync); 91 : : 92 : : /* vm_ops->page_mkwrite handler */ 93 : 0 : static vm_fault_t fb_deferred_io_mkwrite(struct vm_fault *vmf) 94 : : { 95 : 0 : struct page *page = vmf->page; 96 : 0 : struct fb_info *info = vmf->vma->vm_private_data; 97 : 0 : struct fb_deferred_io *fbdefio = info->fbdefio; 98 : 0 : struct page *cur; 99 : : 100 : : /* this is a callback we get when userspace first tries to 101 : : write to the page. we schedule a workqueue. that workqueue 102 : : will eventually mkclean the touched pages and execute the 103 : : deferred framebuffer IO. then if userspace touches a page 104 : : again, we repeat the same scheme */ 105 : : 106 : 0 : file_update_time(vmf->vma->vm_file); 107 : : 108 : : /* protect against the workqueue changing the page list */ 109 : 0 : mutex_lock(&fbdefio->lock); 110 : : 111 : : /* first write in this cycle, notify the driver */ 112 [ # # # # ]: 0 : if (fbdefio->first_io && list_empty(&fbdefio->pagelist)) 113 : 0 : fbdefio->first_io(info); 114 : : 115 : : /* 116 : : * We want the page to remain locked from ->page_mkwrite until 117 : : * the PTE is marked dirty to avoid page_mkclean() being called 118 : : * before the PTE is updated, which would leave the page ignored 119 : : * by defio. 120 : : * Do this by locking the page here and informing the caller 121 : : * about it with VM_FAULT_LOCKED. 122 : : */ 123 : 0 : lock_page(page); 124 : : 125 : : /* we loop through the pagelist before adding in order 126 : : to keep the pagelist sorted */ 127 [ # # ]: 0 : list_for_each_entry(cur, &fbdefio->pagelist, lru) { 128 : : /* this check is to catch the case where a new 129 : : process could start writing to the same page 130 : : through a new pte. this new access can cause the 131 : : mkwrite even when the original ps's pte is marked 132 : : writable */ 133 [ # # ]: 0 : if (unlikely(cur == page)) 134 : 0 : goto page_already_added; 135 [ # # ]: 0 : else if (cur->index > page->index) 136 : : break; 137 : : } 138 : : 139 : 0 : list_add_tail(&page->lru, &cur->lru); 140 : : 141 : 0 : page_already_added: 142 : 0 : mutex_unlock(&fbdefio->lock); 143 : : 144 : : /* come back after delay to process the deferred IO */ 145 : 0 : schedule_delayed_work(&info->deferred_work, fbdefio->delay); 146 : 0 : return VM_FAULT_LOCKED; 147 : : } 148 : : 149 : : static const struct vm_operations_struct fb_deferred_io_vm_ops = { 150 : : .fault = fb_deferred_io_fault, 151 : : .page_mkwrite = fb_deferred_io_mkwrite, 152 : : }; 153 : : 154 : 0 : static int fb_deferred_io_set_page_dirty(struct page *page) 155 : : { 156 [ # # ]: 0 : if (!PageDirty(page)) 157 : 0 : SetPageDirty(page); 158 : 0 : return 0; 159 : : } 160 : : 161 : : static const struct address_space_operations fb_deferred_io_aops = { 162 : : .set_page_dirty = fb_deferred_io_set_page_dirty, 163 : : }; 164 : : 165 : 0 : int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma) 166 : : { 167 : 0 : vma->vm_ops = &fb_deferred_io_vm_ops; 168 : 0 : vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; 169 [ # # ]: 0 : if (!(info->flags & FBINFO_VIRTFB)) 170 : 0 : vma->vm_flags |= VM_IO; 171 : 0 : vma->vm_private_data = info; 172 : 0 : return 0; 173 : : } 174 : : 175 : : /* workqueue callback */ 176 : 0 : static void fb_deferred_io_work(struct work_struct *work) 177 : : { 178 : 0 : struct fb_info *info = container_of(work, struct fb_info, 179 : : deferred_work.work); 180 : 0 : struct list_head *node, *next; 181 : 0 : struct page *cur; 182 : 0 : struct fb_deferred_io *fbdefio = info->fbdefio; 183 : : 184 : : /* here we mkclean the pages, then do all deferred IO */ 185 : 0 : mutex_lock(&fbdefio->lock); 186 [ # # ]: 0 : list_for_each_entry(cur, &fbdefio->pagelist, lru) { 187 : 0 : lock_page(cur); 188 : 0 : page_mkclean(cur); 189 : 0 : unlock_page(cur); 190 : : } 191 : : 192 : : /* driver's callback with pagelist */ 193 : 0 : fbdefio->deferred_io(info, &fbdefio->pagelist); 194 : : 195 : : /* clear the list */ 196 [ # # ]: 0 : list_for_each_safe(node, next, &fbdefio->pagelist) { 197 : 0 : list_del(node); 198 : : } 199 : 0 : mutex_unlock(&fbdefio->lock); 200 : 0 : } 201 : : 202 : 0 : void fb_deferred_io_init(struct fb_info *info) 203 : : { 204 : 0 : struct fb_deferred_io *fbdefio = info->fbdefio; 205 : : 206 [ # # ]: 0 : BUG_ON(!fbdefio); 207 : 0 : mutex_init(&fbdefio->lock); 208 : 0 : INIT_DELAYED_WORK(&info->deferred_work, fb_deferred_io_work); 209 [ # # ]: 0 : INIT_LIST_HEAD(&fbdefio->pagelist); 210 [ # # ]: 0 : if (fbdefio->delay == 0) /* set a default of 1 s */ 211 : 0 : fbdefio->delay = HZ; 212 : 0 : } 213 : : EXPORT_SYMBOL_GPL(fb_deferred_io_init); 214 : : 215 : 0 : void fb_deferred_io_open(struct fb_info *info, 216 : : struct inode *inode, 217 : : struct file *file) 218 : : { 219 : 0 : file->f_mapping->a_ops = &fb_deferred_io_aops; 220 : 0 : } 221 : : EXPORT_SYMBOL_GPL(fb_deferred_io_open); 222 : : 223 : 0 : void fb_deferred_io_cleanup(struct fb_info *info) 224 : : { 225 : 0 : struct fb_deferred_io *fbdefio = info->fbdefio; 226 : 0 : struct page *page; 227 : 0 : int i; 228 : : 229 [ # # ]: 0 : BUG_ON(!fbdefio); 230 : 0 : cancel_delayed_work_sync(&info->deferred_work); 231 : : 232 : : /* clear out the mapping that we setup */ 233 [ # # ]: 0 : for (i = 0 ; i < info->fix.smem_len; i += PAGE_SIZE) { 234 : 0 : page = fb_deferred_io_page(info, i); 235 : 0 : page->mapping = NULL; 236 : : } 237 : : 238 : 0 : mutex_destroy(&fbdefio->lock); 239 : 0 : } 240 : : EXPORT_SYMBOL_GPL(fb_deferred_io_cleanup);