[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>

1 files changed, 36 insertions, 60 deletions

diff --git a/drivers/video/fbcmap.c b/drivers/video/fbcmap.c
index 4e5ce8f7d65e..c32a2a50bfa2 100644
--- 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;
 }
 
 /**