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240 lines
6.2 KiB
240 lines
6.2 KiB
/* |
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* linux/drivers/video/fb_defio.c |
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* |
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* Copyright (C) 2006 Jaya Kumar |
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* |
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* This file is subject to the terms and conditions of the GNU General Public |
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* License. See the file COPYING in the main directory of this archive |
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* for more details. |
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*/ |
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#include <linux/module.h> |
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#include <linux/kernel.h> |
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#include <linux/errno.h> |
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#include <linux/string.h> |
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#include <linux/mm.h> |
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#include <linux/vmalloc.h> |
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#include <linux/delay.h> |
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#include <linux/interrupt.h> |
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#include <linux/fb.h> |
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#include <linux/list.h> |
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/* to support deferred IO */ |
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#include <linux/rmap.h> |
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#include <linux/pagemap.h> |
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static struct page *fb_deferred_io_page(struct fb_info *info, unsigned long offs) |
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{ |
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void *screen_base = (void __force *) info->screen_base; |
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struct page *page; |
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if (is_vmalloc_addr(screen_base + offs)) |
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page = vmalloc_to_page(screen_base + offs); |
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else |
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page = pfn_to_page((info->fix.smem_start + offs) >> PAGE_SHIFT); |
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return page; |
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} |
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/* this is to find and return the vmalloc-ed fb pages */ |
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static vm_fault_t fb_deferred_io_fault(struct vm_fault *vmf) |
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{ |
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unsigned long offset; |
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struct page *page; |
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struct fb_info *info = vmf->vma->vm_private_data; |
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offset = vmf->pgoff << PAGE_SHIFT; |
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if (offset >= info->fix.smem_len) |
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return VM_FAULT_SIGBUS; |
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page = fb_deferred_io_page(info, offset); |
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if (!page) |
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return VM_FAULT_SIGBUS; |
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get_page(page); |
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if (vmf->vma->vm_file) |
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page->mapping = vmf->vma->vm_file->f_mapping; |
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else |
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printk(KERN_ERR "no mapping available\n"); |
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BUG_ON(!page->mapping); |
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page->index = vmf->pgoff; |
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vmf->page = page; |
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return 0; |
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} |
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int fb_deferred_io_fsync(struct file *file, loff_t start, loff_t end, int datasync) |
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{ |
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struct fb_info *info = file->private_data; |
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struct inode *inode = file_inode(file); |
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int err = file_write_and_wait_range(file, start, end); |
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if (err) |
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return err; |
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/* Skip if deferred io is compiled-in but disabled on this fbdev */ |
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if (!info->fbdefio) |
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return 0; |
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inode_lock(inode); |
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/* Kill off the delayed work */ |
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cancel_delayed_work_sync(&info->deferred_work); |
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/* Run it immediately */ |
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schedule_delayed_work(&info->deferred_work, 0); |
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inode_unlock(inode); |
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return 0; |
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} |
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EXPORT_SYMBOL_GPL(fb_deferred_io_fsync); |
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/* vm_ops->page_mkwrite handler */ |
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static vm_fault_t fb_deferred_io_mkwrite(struct vm_fault *vmf) |
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{ |
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struct page *page = vmf->page; |
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struct fb_info *info = vmf->vma->vm_private_data; |
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struct fb_deferred_io *fbdefio = info->fbdefio; |
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struct page *cur; |
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/* this is a callback we get when userspace first tries to |
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write to the page. we schedule a workqueue. that workqueue |
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will eventually mkclean the touched pages and execute the |
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deferred framebuffer IO. then if userspace touches a page |
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again, we repeat the same scheme */ |
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file_update_time(vmf->vma->vm_file); |
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/* protect against the workqueue changing the page list */ |
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mutex_lock(&fbdefio->lock); |
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/* first write in this cycle, notify the driver */ |
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if (fbdefio->first_io && list_empty(&fbdefio->pagelist)) |
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fbdefio->first_io(info); |
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/* |
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* We want the page to remain locked from ->page_mkwrite until |
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* the PTE is marked dirty to avoid page_mkclean() being called |
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* before the PTE is updated, which would leave the page ignored |
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* by defio. |
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* Do this by locking the page here and informing the caller |
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* about it with VM_FAULT_LOCKED. |
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*/ |
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lock_page(page); |
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/* we loop through the pagelist before adding in order |
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to keep the pagelist sorted */ |
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list_for_each_entry(cur, &fbdefio->pagelist, lru) { |
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/* this check is to catch the case where a new |
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process could start writing to the same page |
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through a new pte. this new access can cause the |
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mkwrite even when the original ps's pte is marked |
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writable */ |
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if (unlikely(cur == page)) |
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goto page_already_added; |
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else if (cur->index > page->index) |
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break; |
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} |
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list_add_tail(&page->lru, &cur->lru); |
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page_already_added: |
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mutex_unlock(&fbdefio->lock); |
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/* come back after delay to process the deferred IO */ |
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schedule_delayed_work(&info->deferred_work, fbdefio->delay); |
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return VM_FAULT_LOCKED; |
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} |
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static const struct vm_operations_struct fb_deferred_io_vm_ops = { |
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.fault = fb_deferred_io_fault, |
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.page_mkwrite = fb_deferred_io_mkwrite, |
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}; |
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static int fb_deferred_io_set_page_dirty(struct page *page) |
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{ |
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if (!PageDirty(page)) |
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SetPageDirty(page); |
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return 0; |
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} |
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static const struct address_space_operations fb_deferred_io_aops = { |
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.set_page_dirty = fb_deferred_io_set_page_dirty, |
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}; |
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int fb_deferred_io_mmap(struct fb_info *info, struct vm_area_struct *vma) |
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{ |
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vma->vm_ops = &fb_deferred_io_vm_ops; |
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vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP; |
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if (!(info->flags & FBINFO_VIRTFB)) |
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vma->vm_flags |= VM_IO; |
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vma->vm_private_data = info; |
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return 0; |
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} |
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/* workqueue callback */ |
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static void fb_deferred_io_work(struct work_struct *work) |
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{ |
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struct fb_info *info = container_of(work, struct fb_info, |
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deferred_work.work); |
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struct list_head *node, *next; |
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struct page *cur; |
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struct fb_deferred_io *fbdefio = info->fbdefio; |
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/* here we mkclean the pages, then do all deferred IO */ |
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mutex_lock(&fbdefio->lock); |
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list_for_each_entry(cur, &fbdefio->pagelist, lru) { |
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lock_page(cur); |
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page_mkclean(cur); |
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unlock_page(cur); |
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} |
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/* driver's callback with pagelist */ |
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fbdefio->deferred_io(info, &fbdefio->pagelist); |
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/* clear the list */ |
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list_for_each_safe(node, next, &fbdefio->pagelist) { |
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list_del(node); |
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} |
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mutex_unlock(&fbdefio->lock); |
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} |
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void fb_deferred_io_init(struct fb_info *info) |
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{ |
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struct fb_deferred_io *fbdefio = info->fbdefio; |
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BUG_ON(!fbdefio); |
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mutex_init(&fbdefio->lock); |
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INIT_DELAYED_WORK(&info->deferred_work, fb_deferred_io_work); |
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INIT_LIST_HEAD(&fbdefio->pagelist); |
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if (fbdefio->delay == 0) /* set a default of 1 s */ |
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fbdefio->delay = HZ; |
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} |
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EXPORT_SYMBOL_GPL(fb_deferred_io_init); |
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void fb_deferred_io_open(struct fb_info *info, |
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struct inode *inode, |
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struct file *file) |
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{ |
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file->f_mapping->a_ops = &fb_deferred_io_aops; |
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} |
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EXPORT_SYMBOL_GPL(fb_deferred_io_open); |
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void fb_deferred_io_cleanup(struct fb_info *info) |
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{ |
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struct fb_deferred_io *fbdefio = info->fbdefio; |
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struct page *page; |
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int i; |
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BUG_ON(!fbdefio); |
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cancel_delayed_work_sync(&info->deferred_work); |
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/* clear out the mapping that we setup */ |
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for (i = 0 ; i < info->fix.smem_len; i += PAGE_SIZE) { |
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page = fb_deferred_io_page(info, i); |
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page->mapping = NULL; |
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} |
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mutex_destroy(&fbdefio->lock); |
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} |
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EXPORT_SYMBOL_GPL(fb_deferred_io_cleanup);
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