[PATCH] fbdev: update info->cmap when setting cmap from user-/kernelspace.

The fb_info struct, as defined in include/linux/fb.h, contains an element
that is supposed to hold the current color map:
  struct fb_cmap cmap;            /* Current cmap */

This cmap is currently never updated when either fb_set_cmap() or
fb_set_user_cmap() are called.  As a result, info->cmap contains the
default cmap that was set by a device driver/fbcon and a userspace
application using the FBIOGETCMAP ioctl will not always get the *currently*
used color map.

The patch fixes this by making sure the cmap is copied to info->cmap after
it is set correctly.  It moves most of the code that is responsible for
setting the cmap to fb_set_cmap() and out of fb_set_user_cmap() to avoid
code-duplication.

Signed-off-by: Michal Januszewski <spock@gentoo.org>
Cc: <linux-fbdev-devel@lists.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/drivers/video/fbcmap.c b/drivers/video/fbcmap.c
index 4e5ce8f..c32a2a5 100644 (file)
--- a/drivers/video/fbcmap.c
+++ b/drivers/video/fbcmap.c
@@ -212,7 +212,7 @@ int fb_cmap_to_user(struct fb_cmap *from, struct fb_cmap_user *to)
 
 int fb_set_cmap(struct fb_cmap *cmap, struct fb_info *info)
 {
-       int i, start;
+       int i, start, rc = 0;
        u16 *red, *green, *blue, *transp;
        u_int hred, hgreen, hblue, htransp = 0xffff;
 
@@ -225,75 +225,51 @@ int fb_set_cmap(struct fb_cmap *cmap, struct fb_info *info)
        if (start < 0 || (!info->fbops->fb_setcolreg &&
                          !info->fbops->fb_setcmap))
                return -EINVAL;
-       if (info->fbops->fb_setcmap)
-               return info->fbops->fb_setcmap(cmap, info);
-       for (i = 0; i < cmap->len; i++) {
-               hred = *red++;
-               hgreen = *green++;
-               hblue = *blue++;
-               if (transp)
-                       htransp = *transp++;
-               if (info->fbops->fb_setcolreg(start++,
-                                             hred, hgreen, hblue, htransp,
-                                             info))
-                       break;
+       if (info->fbops->fb_setcmap) {
+               rc = info->fbops->fb_setcmap(cmap, info);
+       } else {
+               for (i = 0; i < cmap->len; i++) {
+                       hred = *red++;
+                       hgreen = *green++;
+                       hblue = *blue++;
+                       if (transp)
+                               htransp = *transp++;
+                       if (info->fbops->fb_setcolreg(start++,
+                                                     hred, hgreen, hblue,
+                                                     htransp, info))
+                               break;
+               }
        }
-       return 0;
+       if (rc == 0)
+               fb_copy_cmap(cmap, &info->cmap);
+
+       return rc;
 }
 
 int fb_set_user_cmap(struct fb_cmap_user *cmap, struct fb_info *info)
 {
-       int i, start;
-       u16 __user *red, *green, *blue, *transp;
-       u_int hred, hgreen, hblue, htransp = 0xffff;
-
-       red = cmap->red;
-       green = cmap->green;
-       blue = cmap->blue;
-       transp = cmap->transp;
-       start = cmap->start;
+       int rc, size = cmap->len * sizeof(u16);
+       struct fb_cmap umap;
 
-       if (start < 0 || (!info->fbops->fb_setcolreg &&
-                         !info->fbops->fb_setcmap))
+       if (cmap->start < 0 || (!info->fbops->fb_setcolreg &&
+                               !info->fbops->fb_setcmap))
                return -EINVAL;
 
-       /* If we can batch, do it */
-       if (info->fbops->fb_setcmap && cmap->len > 1) {
-               struct fb_cmap umap;
-               int size = cmap->len * sizeof(u16);
-               int rc;
-
-               memset(&umap, 0, sizeof(struct fb_cmap));
-               rc = fb_alloc_cmap(&umap, cmap->len, transp != NULL);
-               if (rc)
-                       return rc;
-               if (copy_from_user(umap.red, red, size) ||
-                   copy_from_user(umap.green, green, size) ||
-                   copy_from_user(umap.blue, blue, size) ||
-                   (transp && copy_from_user(umap.transp, transp, size))) {
-                       rc = -EFAULT;
-               }
-               umap.start = start;
-               if (rc == 0)
-                       rc = info->fbops->fb_setcmap(&umap, info);
-               fb_dealloc_cmap(&umap);
+       memset(&umap, 0, sizeof(struct fb_cmap));
+       rc = fb_alloc_cmap(&umap, cmap->len, cmap->transp != NULL);
+       if (rc)
                return rc;
+       if (copy_from_user(umap.red, cmap->red, size) ||
+           copy_from_user(umap.green, cmap->green, size) ||
+           copy_from_user(umap.blue, cmap->blue, size) ||
+           (cmap->transp && copy_from_user(umap.transp, cmap->transp, size))) {
+               fb_dealloc_cmap(&umap);
+               return -EFAULT;
        }
-
-       for (i = 0; i < cmap->len; i++, red++, blue++, green++) {
-               if (get_user(hred, red) ||
-                   get_user(hgreen, green) ||
-                   get_user(hblue, blue) ||
-                   (transp && get_user(htransp, transp)))
-                       return -EFAULT;
-               if (info->fbops->fb_setcolreg(start++,
-                                             hred, hgreen, hblue, htransp,
-                                             info))
-                       return 0;
-               if (transp)
-                       transp++;
-       }
-       return 0;
+       umap.start = cmap->start;
+       rc = fb_set_cmap(&umap, info);
+       fb_dealloc_cmap(&umap);
+       return rc;
 }
 
 /**