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