fb_defio: redo fix for non-dirty ptes

[safe/jmp/linux-2.6] / drivers / video / fb_defio.c

diff --git a/drivers/video/fb_defio.c b/drivers/video/fb_defio.c
index 59df132..6b93ef9 100644 (file)
--- a/drivers/video/fb_defio.c
+++ b/drivers/video/fb_defio.c
@@ -13,7 +13,6 @@
 #include <linux/errno.h>
 #include <linux/string.h>
 #include <linux/mm.h>
-#include <linux/slab.h>
 #include <linux/vmalloc.h>
 #include <linux/delay.h>
 #include <linux/interrupt.h>
@@ -24,6 +23,19 @@
 #include <linux/rmap.h>
 #include <linux/pagemap.h>
 
+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)
@@ -31,14 +43,12 @@ static int fb_deferred_io_fault(struct vm_area_struct *vma,
        unsigned long offset;
        struct page *page;
        struct fb_info *info = vma->vm_private_data;
-       /* info->screen_base is virtual memory */
-       void *screen_base = (void __force *) info->screen_base;
 
        offset = vmf->pgoff << PAGE_SHIFT;
        if (offset >= info->fix.smem_len)
                return VM_FAULT_SIGBUS;
 
-       page = vmalloc_to_page(screen_base + offset);
+       page = fb_deferred_io_page(info, offset);
        if (!page)
                return VM_FAULT_SIGBUS;
 
@@ -56,10 +66,14 @@ static int fb_deferred_io_fault(struct vm_area_struct *vma,
        return 0;
 }
 
-int fb_deferred_io_fsync(struct file *file, struct dentry *dentry, int datasync)
+int fb_deferred_io_fsync(struct file *file, int datasync)
 {
        struct fb_info *info = file->private_data;
 
+       /* Skip if deferred io is compiled-in but disabled on this fbdev */
+       if (!info->fbdefio)
+               return 0;
+
        /* Kill off the delayed work */
        cancel_rearming_delayed_work(&info->deferred_work);
 
@@ -70,8 +84,9 @@ EXPORT_SYMBOL_GPL(fb_deferred_io_fsync);
 
 /* vm_ops->page_mkwrite handler */
 static int fb_deferred_io_mkwrite(struct vm_area_struct *vma,
-                                 struct page *page)
+                                 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;
@@ -85,6 +100,16 @@ static int fb_deferred_io_mkwrite(struct vm_area_struct *vma,
        /* protect against the workqueue changing the page list */
        mutex_lock(&fbdefio->lock);
 
+       /*
+        * 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) {
@@ -106,18 +131,31 @@ page_already_added:
 
        /* come back after delay to process the deferred IO */
        schedule_delayed_work(&info->deferred_work, fbdefio->delay);
-       return 0;
+       return VM_FAULT_LOCKED;
 }
 
-static struct vm_operations_struct fb_deferred_io_vm_ops = {
+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_IO | VM_RESERVED | VM_DONTEXPAND );
+       vma->vm_flags |= ( VM_RESERVED | VM_DONTEXPAND );
+       if (!(info->flags & FBINFO_VIRTFB))
+               vma->vm_flags |= VM_IO;
        vma->vm_private_data = info;
        return 0;
 }
@@ -163,9 +201,16 @@ void fb_deferred_io_init(struct fb_info *info)
 }
 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)
 {
-       void *screen_base = (void __force *) info->screen_base;
        struct fb_deferred_io *fbdefio = info->fbdefio;
        struct page *page;
        int i;
@@ -176,9 +221,12 @@ void fb_deferred_io_cleanup(struct fb_info *info)
 
        /* clear out the mapping that we setup */
        for (i = 0 ; i < info->fix.smem_len; i += PAGE_SIZE) {
-               page = vmalloc_to_page(screen_base + i);
+               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);