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path: root/drivers/tty/tty_ldisc.c
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2010-11-29TTY: ldisc, fix open flag handlingJiri Slaby
When a concrete ldisc open fails in tty_ldisc_open, we forget to clear TTY_LDISC_OPEN. This causes a false warning on the next ldisc open: WARNING: at drivers/char/tty_ldisc.c:445 tty_ldisc_open+0x26/0x38() Hardware name: System Product Name Modules linked in: ... Pid: 5251, comm: a.out Tainted: G W 2.6.32-5-686 #1 Call Trace: [<c1030321>] ? warn_slowpath_common+0x5e/0x8a [<c1030357>] ? warn_slowpath_null+0xa/0xc [<c119311c>] ? tty_ldisc_open+0x26/0x38 [<c11936c5>] ? tty_set_ldisc+0x218/0x304 ... So clear the bit when failing... Introduced in c65c9bc3efa (tty: rewrite the ldisc locking) back in 2.6.31-rc1. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: Alan Cox <alan@linux.intel.com> Reported-by: Sergey Lapin <slapin@ossfans.org> Tested-by: Sergey Lapin <slapin@ossfans.org> Cc: stable <stable@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-11-09tty_ldisc: Fix BUG() on hangupPhilippe Rétornaz
A kernel BUG when bluetooth rfcomm connection drop while the associated serial port is open is sometime triggered. It seems that the line discipline can disappear between the tty_ldisc_put and tty_ldisc_get. This patch fall back to the N_TTY line discipline if the previous discipline is not available anymore. Signed-off-by: Philippe Retornaz <philippe.retornaz@epfl.ch> Acked-by: Alan Cox <alan@linux.intel.com> Cc: stable <stable@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-11-09TTY: restore tty_ldisc_wait_idleJiri Slaby
It was removed in 65b770468e98 (tty-ldisc: turn ldisc user count into a proper refcount), but we need to wait for last user to quit the ldisc before we close it in tty_set_ldisc. Otherwise weird things start to happen. There might be processes waiting in tty_read->n_tty_read on tty->read_wait for input to appear and at that moment, a change of ldisc is fatal. n_tty_close is called, it frees read_buf and the waiting process is still in the middle of reading and goes nuts after it is woken. Previously we prevented close to happen when others are in ldisc ops by tty_ldisc_wait_idle in tty_set_ldisc. But the commit above removed that. So revoke the change and test whether there is 1 user (=we), and allow the close then. We can do that without ldisc/tty locks, because nobody else can open the device due to TTY_LDISC_CHANGING bit set, so we in fact wait for everybody to leave. I don't understand why tty_ldisc_lock would be needed either when the counter is an atomic variable, so this is a lockless tty_ldisc_wait_idle. On the other hand, if we fail to wait (timeout or signal), we have to reenable the halted ldiscs, so we take ldisc lock and reuse the setup path at the end of tty_set_ldisc. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Tested-by: Sebastian Andrzej Siewior <bigeasy@breakpoint.cc> LKML-Reference: <20101031104136.GA511@Chamillionaire.breakpoint.cc> LKML-Reference: <1287669539-22644-1-git-send-email-jslaby@suse.cz> Cc: Alan Cox <alan@linux.intel.com> Cc: stable@kernel.org [32, 33, 36] Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-11-05TTY: create drivers/tty and move the tty core files thereGreg Kroah-Hartman
The tty code should be in its own subdirectory and not in the char driver with all of the cruft that is currently there. Based on work done by Arnd Bergmann <arnd@arndb.de> Acked-by: Arnd Bergmann <arnd@arndb.de> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>