tree 6ffcd907c45b10c88d71d372bde9d437e68b7e6b
parent 979990c6284814617d8f2179d197f72ff62b5d85
author Arnd Bergmann <arnd@arndb.de> 1497993042 +0200
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1501426339 -0700

tty: improve tty_insert_flip_char() slow path

While working on improving the fast path of tty_insert_flip_char(),
I noticed that by calling tty_buffer_request_room(), we needlessly
move to the separate flag buffer mode for the tty, even when all
characters use TTY_NORMAL as the flag.

This changes the code to call __tty_buffer_request_room() with the
correct flag, which will then allocate a regular buffer when it rounds
out of space but no special flags have been used. I'm guessing that
this is the behavior that Peter Hurley intended when he introduced
the compacted flip buffers.

Fixes: acc0f67f307f ("tty: Halve flip buffer GFP_ATOMIC memory consumption")
Cc: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>