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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-05 21:46:07 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-05 21:46:07 +0200 |
| commit | 37f81fa1f63ad38e16125526bb2769ae0ea8d332 (patch) | |
| tree | 116ee462263777d2cd12b578b60ffe04a8a5b38c /drivers/char | |
| parent | exec: do not sleep in TASK_TRACED under ->cred_guard_mutex (diff) | |
| download | linux-37f81fa1f63ad38e16125526bb2769ae0ea8d332.tar.xz linux-37f81fa1f63ad38e16125526bb2769ae0ea8d332.zip | |
n_tty: do O_ONLCR translation as a single write
When translating CR to CRNL in the n_tty line discipline, we did it as
two tty_put_char() calls. Which works, but is stupid, and has caused
problems before too with bad interactions with the write_room() logic.
The generic USB serial driver had that problem, for example.
Now the pty layer had similar issues after being moved to the generic
tty buffering code (in commit d945cb9cce20ac7143c2de8d88b187f62db99bdc:
"pty: Rework the pty layer to use the normal buffering logic").
So stop doing the silly separate two writes, and do it as a single write
instead. That's what the n_tty layer already does for the space
expansion of tabs (XTABS), and it means that we'll now always have just
a single write for the CRNL to match the single 'tty_write_room()' test,
which hopefully means that the next time somebody screws up buffering,
it won't cause weeks of debugging.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to '')
| -rw-r--r-- | drivers/char/n_tty.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/drivers/char/n_tty.c b/drivers/char/n_tty.c index 973be2f44195..4e28b35024ec 100644 --- a/drivers/char/n_tty.c +++ b/drivers/char/n_tty.c @@ -300,8 +300,7 @@ static int do_output_char(unsigned char c, struct tty_struct *tty, int space) if (space < 2) return -1; tty->canon_column = tty->column = 0; - tty_put_char(tty, '\r'); - tty_put_char(tty, c); + tty->ops->write(tty, "\r\n", 2); return 2; } tty->canon_column = tty->column; |