fbcon: Include font geometry in the rotated font cache

fbcon_rotate_font() caches a rotated copy of the console font and
skips the rebuild when the fontdata pointer and the rotation match.
Raw font data carries no geometry, though: width, height and
charcount live in vc->vc_font. fbcon_set_font() deduplicates uploads
by byte equality, so the same bytes re-uploaded with different
dimensions keep the fontdata pointer while the geometry changes, and
the early-out skips the rebuild.

The rotated cell size depends on the geometry (rotation swaps width
and height), so the stale buffer is indexed with the new cell size.
Re-uploading a 4x16 font as 16x8 on a CW-rotated console, for
example, doubles the rotated cell size and reads past the end of the
old buffer.

Record the geometry the buffer was built from and compare it in the
early-out. The pointer-only key used to be backed by an explicit
width check in the deduplication, which commit 1e3c49aa03fb
("lib/fonts: Compare font data for equality with font_data_is_equal()")
dropped.

Fixes: 6cc50e1c5b57 ("[PATCH] fbcon: Console Rotation - Add support to rotate font bitmap")
Cc: stable@vger.kernel.org
Signed-off-by: Yao Yiqi <yaoyiqi3@huawei.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Helge Deller <deller@gmx.de>

0 files changed, 0 insertions, 0 deletions