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Subject[PATCH 1/3] fbdev: simplify fb_getput_cmap()
Date
This function is one of the remaining users of compat_alloc_user_space()
and copy_in_user().

Clean it up by copying to a local data structure copy instead,
which also leads to more readable code.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
drivers/video/fbdev/core/fbmem.c | 44 ++++++++++++++------------------
1 file changed, 19 insertions(+), 25 deletions(-)

diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c
index da7c88ffaa6a..4e162e3d3538 100644
--- a/drivers/video/fbdev/core/fbmem.c
+++ b/drivers/video/fbdev/core/fbmem.c
@@ -1211,36 +1211,30 @@ struct fb_cmap32 {
static int fb_getput_cmap(struct fb_info *info, unsigned int cmd,
unsigned long arg)
{
- struct fb_cmap_user __user *cmap;
- struct fb_cmap32 __user *cmap32;
- __u32 data;
- int err;
-
- cmap = compat_alloc_user_space(sizeof(*cmap));
- cmap32 = compat_ptr(arg);
+ struct fb_cmap32 cmap32;
+ struct fb_cmap cmap_from;
+ struct fb_cmap_user cmap;

- if (copy_in_user(&cmap->start, &cmap32->start, 2 * sizeof(__u32)))
+ if (copy_from_user(&cmap32, compat_ptr(arg), sizeof(cmap32)))
return -EFAULT;

- if (get_user(data, &cmap32->red) ||
- put_user(compat_ptr(data), &cmap->red) ||
- get_user(data, &cmap32->green) ||
- put_user(compat_ptr(data), &cmap->green) ||
- get_user(data, &cmap32->blue) ||
- put_user(compat_ptr(data), &cmap->blue) ||
- get_user(data, &cmap32->transp) ||
- put_user(compat_ptr(data), &cmap->transp))
- return -EFAULT;
+ cmap = (struct fb_cmap_user) {
+ .start = cmap32.start,
+ .len = cmap32.len,
+ .red = compat_ptr(cmap32.red),
+ .green = compat_ptr(cmap32.green),
+ .blue = compat_ptr(cmap32.blue),
+ .transp = compat_ptr(cmap32.transp),
+ };

- err = do_fb_ioctl(info, cmd, (unsigned long) cmap);
+ if (cmd == FBIOPUTCMAP)
+ return fb_set_user_cmap(&cmap, info);

- if (!err) {
- if (copy_in_user(&cmap32->start,
- &cmap->start,
- 2 * sizeof(__u32)))
- err = -EFAULT;
- }
- return err;
+ lock_fb_info(info);
+ cmap_from = info->cmap;
+ unlock_fb_info(info);
+
+ return fb_cmap_to_user(&cmap_from, &cmap);
}

static int do_fscreeninfo_to_user(struct fb_fix_screeninfo *fix,
--
2.27.0
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