[34-longterm 198/247] isdn: avoid calling tty_ldisc_flush() in atomic context

Paul Gortmaker
2011-06-23T17:53:14Z

From: Tilman Schmidt <tilman@imap.cc>

-------------------
This is a commit scheduled for the next v2.6.34 longterm release.
If you see a problem with using this for longterm, please comment.
-------------------

commit bc10f96757bd6ab3721510df8defa8f21c32f974 upstream.

Remove the call to tty_ldisc_flush() from the RESULT_NO_CARRIER
branch of isdn_tty_modem_result(), as already proposed in commit
00409bb045887ec5e7b9e351bc080c38ab6bfd33.
This avoids a "sleeping function called from invalid context" BUG
when the hardware driver calls the statcallb() callback with
command==ISDN_STAT_DHUP in atomic context, which in turn calls
isdn_tty_modem_result(RESULT_NO_CARRIER, ~), and from there,
tty_ldisc_flush() which may sleep.

Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
drivers/isdn/i4l/isdn_tty.c | 6 ------
1 files changed, 0 insertions(+), 6 deletions(-)

diff --git a/drivers/isdn/i4l/isdn_tty.c b/drivers/isdn/i4l/isdn_tty.c
index fc8454d..51dc60d 100644
--- a/drivers/isdn/i4l/isdn_tty.c
+++ b/drivers/isdn/i4l/isdn_tty.c
@@ -2636,12 +2636,6 @@ isdn_tty_modem_result(int code, modem_info * info)
if ((info->flags & ISDN_ASYNC_CLOSING) || (!info->tty)) {
return;
}
-#ifdef CONFIG_ISDN_AUDIO
- if ( !info->vonline )
- tty_ldisc_flush(info->tty);
-#else
- tty_ldisc_flush(info->tty);
-#endif
if ((info->flags & ISDN_ASYNC_CHECK_CD) &&
(!((info->flags & ISDN_ASYNC_CALLOUT_ACTIVE) &&
(info->flags & ISDN_ASYNC_CALLOUT_NOHUP)))) {
--
1.7.4.4