Messages in this thread Patch in this message | | | From | Peter Hurley <> | Subject | [PATCH] n_tty: Fix poll() when TIME_CHAR and MIN_CHAR == 0 | Date | Tue, 11 Feb 2014 11:49:58 -0500 |
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On 02/11/2014 07:14 AM, Arnaldo Carvalho de Melo wrote: > Em Mon, Feb 10, 2014 at 09:15:42PM -0500, Peter Hurley escreveu: >>> Bisected it down to: > >>> eb3e4668bd9e0bbda592e830e889f137e44ec9e4 is the first bad commit >>> Author: Peter Hurley <peter@hurleysoftware.com> >>> Date: Mon Dec 2 14:24:42 2013 -0500 > >>> n_tty: Un-inline slow-path n_tty_receive_char() > >>> In a hurry now, will continue later, trying to understand what is the problem >>> introduced by the above cset... > >>> Need to revert just this one to confirm that it is the culprit, etc. > >> Thanks for the report and bisect. Seems unlikely this commit is the >> cause, but very likely to be some change I made since 3.13, since >> I can repro on 3.14-rc1 but not on 3.13.2 -stable. I can also repro >> this on 3.12 + the patch stack from me for 3.13 and 3.14. > >> I'm looking into this now. > > I just reverted just this cset and the problem persisted, so I'll wait > for you on this one :-)
My bisection pointed to:
eafbe67f84761d787802e5113d895a316b6292fe is the first bad commit commit eafbe67f84761d787802e5113d895a316b6292fe Author: Peter Hurley <peter@hurleysoftware.com> Date: Mon Dec 2 14:24:45 2013 -0500
n_tty: Refactor input_available_p() by call site
Apologies for the breakage; the patch below should fix it.
Regards, Peter Hurley
--- >% --- From: Peter Hurley <peter@hurleysoftware.com> Date: Tue, 11 Feb 2014 10:10:07 -0500 Subject: [PATCH] n_tty: Fix poll() when TIME_CHAR and MIN_CHAR == 0
Commit eafbe67f84761d787802e5113d895a316b6292fe, n_tty: Refactor input_available_p() by call site broke poll() when TIME_CHAR(tty) and MIN_CHAR(tty) are both 0.
When TIME_CHAR and MIN_CHAR are both 0, input is available if the read_cnt is 1 (not 0).
Reported-by: Stephane Eranian <eranian@google.com> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> --- drivers/tty/n_tty.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c index cb8017a..2747a3b 100644 --- a/drivers/tty/n_tty.c +++ b/drivers/tty/n_tty.c @@ -1896,7 +1896,7 @@ err: static inline int input_available_p(struct tty_struct *tty, int poll) { struct n_tty_data *ldata = tty->disc_data; - int amt = poll && !TIME_CHAR(tty) ? MIN_CHAR(tty) : 1; + int amt = poll && !TIME_CHAR(tty) && MIN_CHAR(tty) ? MIN_CHAR(tty) : 1; if (ldata->icanon && !L_EXTPROC(tty)) { if (ldata->canon_head != ldata->read_tail) -- 1.8.1.2
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