Commit Graph

361079 Commits

Author SHA1 Message Date
Peter Hurley 96433d104a tty: Bracket ldisc release with TTY_DEBUG_HANGUP messages
Expected typical log output:
[    2.437211] tty_open: opening pts1...
[    2.443376] tty_open: opening pts5...
[    2.447830] tty_release: ptm0 (tty count=1)...
[    2.447849] pts0 vhangup...
[    2.447865] tty_release: ptm0: final close
[    2.447876] tty_release: ptm0: freeing structure...
[    2.451634] tty_release: tty1 (tty count=1)...
[    2.451638] tty_release: tty1: final close
[    2.451654] tty_release: tty1: freeing structure...
[    2.452505] tty_release: pts5 (tty count=2)...
[    2.453029] tty_open: opening pts0...

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:46:30 -07:00
Peter Hurley c878524174 tty: Fix 'deferred reopen' ldisc comment
This comment is a victim of code migration from
"tty: Fix the ldisc hangup race"; re-parent it.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:44:02 -07:00
Peter Hurley a2965b7bee tty: Make core responsible for synchronizing its work
The tty core relies on the ldisc layer for synchronizing destruction
of the tty. Instead, the final tty release must wait for any pending tty
work to complete prior to tty destruction.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:44:02 -07:00
Peter Hurley 4f98d46751 tty: Complete ownership transfer of flip buffers
Waiting for buffer work to complete is not required for safely
performing changes to the line discipline, once the line discipline
is halted. The buffer work routine, flush_to_ldisc(), will be
unable to acquire an ldisc ref and all existing references were
waited until released (so it can't already have one).

Ensure running buffer work which may reference the soon-to-be-gone
tty completes and any buffer work running after this point retrieves
a NULL tty.

Also, ensure all buffer work is cancelled on port destruction.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:44:02 -07:00
Peter Hurley d912156605 tty: Don't reenable already enabled ldisc
tty_ldisc_hangup() guarantees the ldisc is enabled (or that there
is no ldisc). Since __tty_hangup() was the only user, re-define
tty_ldisc_enable() in file-scope.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:44:02 -07:00
Peter Hurley b66f4fa509 n_tty: Fully initialize ldisc before restarting buffer work
Buffer work may already be pending when the n_tty ldisc is re-opened,
eg., when setting the ldisc (via TIOCSETD ioctl) and when hanging up
the tty. Since n_tty_set_room() may restart buffer work, first ensure
the ldisc is completely initialized.

Factor n_tty_set_room() out of reset_buffer_flags() (only 2 callers)
and reorganize n_tty_open() to set termios last; buffer work will
be restarted there if necessary, after the char_map is properly
initialized.

Fixes this WARNING:

[  549.561769] ------------[ cut here ]------------
[  549.598755] WARNING: at drivers/tty/n_tty.c:160 n_tty_set_room+0xff/0x130()
[  549.604058] scheduling buffer work for halted ldisc
[  549.607741] Pid: 9417, comm: trinity-child28 Tainted: G      D W 3.7.0-next-20121217-sasha-00023-g8689ef9 #219
[  549.652580] Call Trace:
[  549.662754]  [<ffffffff81c432cf>] ? n_tty_set_room+0xff/0x130
[  549.665458]  [<ffffffff8110cae7>] warn_slowpath_common+0x87/0xb0
[  549.668257]  [<ffffffff8110cb71>] warn_slowpath_fmt+0x41/0x50
[  549.671007]  [<ffffffff81c432cf>] n_tty_set_room+0xff/0x130
[  549.673268]  [<ffffffff81c44597>] reset_buffer_flags+0x137/0x150
[  549.675607]  [<ffffffff81c45b71>] n_tty_open+0x131/0x1c0
[  549.677699]  [<ffffffff81c47824>] tty_ldisc_open.isra.5+0x54/0x70
[  549.680147]  [<ffffffff81c482bf>] tty_ldisc_hangup+0x11f/0x1e0
[  549.682409]  [<ffffffff81c3fa17>] __tty_hangup+0x137/0x440
[  549.684634]  [<ffffffff81c3fd49>] tty_vhangup+0x9/0x10
[  549.686443]  [<ffffffff81c4a42c>] pty_close+0x14c/0x160
[  549.688446]  [<ffffffff81c41225>] tty_release+0xd5/0x490
[  549.690460]  [<ffffffff8127d8a2>] __fput+0x122/0x250
[  549.692577]  [<ffffffff8127d9d9>] ____fput+0x9/0x10
[  549.694534]  [<ffffffff811348c2>] task_work_run+0xb2/0xf0
[  549.696349]  [<ffffffff81113c6d>] do_exit+0x36d/0x580
[  549.698286]  [<ffffffff8107d964>] ? syscall_trace_enter+0x24/0x2e0
[  549.702729]  [<ffffffff81113f4a>] do_group_exit+0x8a/0xc0
[  549.706775]  [<ffffffff81113f92>] sys_exit_group+0x12/0x20
[  549.711088]  [<ffffffff83cfab18>] tracesys+0xe1/0xe6
[  549.728001] ---[ end trace 73eb41728f11f87e ]---

Reported-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:44:01 -07:00
Peter Hurley 25518c68b3 n_tty: Correct unthrottle-with-buffer-flush comments
The driver is no longer unthrottled on buffer reset, so remove
comments that claim it is.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:38:58 -07:00
Peter Hurley 977066e758 tty: Wait for SAK work before waiting for hangup work
SAK work may schedule hangup work (if TTY_SOFT_SAK is defined), thus
SAK work must be flushed before hangup work.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:38:58 -07:00
Peter Hurley f4cf7a3845 tty: Halt both ldiscs concurrently
The pty driver does not obtain an ldisc reference to the linked
tty when writing. When the ldiscs are sequentially halted, it
is possible for one ldisc to be halted, and before the second
ldisc can be halted, a concurrent write schedules buffer work on
the first ldisc. This can lead to an access-after-free error when
the scheduled buffer work starts on the closed ldisc.

Prevent subsequent use after halt by performing each stage
of the halt on both ttys.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:38:58 -07:00
Peter Hurley cf52847658 tty: Strengthen no-subsequent-use guarantee of tty_ldisc_halt()
In preparation for destructing and freeing the tty, the line discipline
must first be brought to an inactive state before it can be destructed.
This line discipline shutdown must:
 - disallow new users of the ldisc
 - wait for existing ldisc users to finish
 - only then, cancel/flush their pending/running work

Factor tty_ldisc_wait_idle() from tty_set_ldisc() and tty_ldisc_kill()
to ensure this shutdown order.

Failure to provide this guarantee can result in scheduled work
running after the tty has already been freed, as indicated in the
following log message:

[   88.331234] WARNING: at drivers/tty/tty_buffer.c:435 flush_to_ldisc+0x194/0x1d0()
[   88.334505] Hardware name: Bochs
[   88.335618] tty is bad=-1
[   88.335703] Modules linked in: netconsole configfs bnep rfcomm bluetooth ......
[   88.345272] Pid: 39, comm: kworker/1:1 Tainted: G        W    3.7.0-next-20121129+ttydebug-xeon #20121129+ttydebug
[   88.347736] Call Trace:
[   88.349024]  [<ffffffff81058aff>] warn_slowpath_common+0x7f/0xc0
[   88.350383]  [<ffffffff81058bf6>] warn_slowpath_fmt+0x46/0x50
[   88.351745]  [<ffffffff81432bd4>] flush_to_ldisc+0x194/0x1d0
[   88.353047]  [<ffffffff816f7fe1>] ? _raw_spin_unlock_irq+0x21/0x50
[   88.354190]  [<ffffffff8108a809>] ? finish_task_switch+0x49/0xe0
[   88.355436]  [<ffffffff81077ad1>] process_one_work+0x121/0x490
[   88.357674]  [<ffffffff81432a40>] ? __tty_buffer_flush+0x90/0x90
[   88.358954]  [<ffffffff81078c84>] worker_thread+0x164/0x3e0
[   88.360247]  [<ffffffff81078b20>] ? manage_workers+0x120/0x120
[   88.361282]  [<ffffffff8107e230>] kthread+0xc0/0xd0
[   88.362284]  [<ffffffff816f0000>] ? cmos_do_probe+0x2eb/0x3bf
[   88.363391]  [<ffffffff8107e170>] ? flush_kthread_worker+0xb0/0xb0
[   88.364797]  [<ffffffff816fff6c>] ret_from_fork+0x7c/0xb0
[   88.366087]  [<ffffffff8107e170>] ? flush_kthread_worker+0xb0/0xb0
[   88.367266] ---[ end trace 453a7c9f38fbfec0 ]---

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:38:58 -07:00
Peter Hurley 11cf48eab2 tty: Relocate tty_ldisc_halt() to avoid forward declaration
tty_ldisc_halt() will use the file-scoped function, tty_ldisc_wait_idle(),
in the following patch.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:38:58 -07:00
Peter Hurley 76bc35e78f tty: Fix ldisc halt sequence on hangup
Flip buffer work cannot be cancelled until all outstanding ldisc
references have been released. Convert the ldisc ref wait into
a full ldisc halt with buffer work cancellation.

Note that the legacy mutex is not held while cancelling.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:32:46 -07:00
Peter Hurley 2276ad9765 tty: Remove unnecessary re-test of ldisc ref count
Since the tty->ldisc is prevented from being changed by tty_set_ldisc()
when a tty is being hung up, re-testing the ldisc user count is
unnecessary -- ie, it cannot be a different ldisc and the user count
cannot have increased (assuming the caller meets the precondition that
TTY_LDISC flag is cleared)

Removal of the 'early-out' locking optimization is necessary for
the subsequent patch 'tty: Fix ldisc halt sequence on hangup'.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:32:46 -07:00
Peter Hurley 168942c9fa tty: Refactor wait for ldisc refs out of tty_ldisc_hangup()
Refactor tty_ldisc_hangup() to extract standalone function,
tty_ldisc_hangup_wait_idle(), to wait for ldisc references
to be released.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:32:46 -07:00
Peter Hurley 79901317ce n_tty: Don't flush buffer when closing ldisc
A buffer flush is both undesirable and unnecessary when the ldisc
is closing. A buffer flush performs the following:
 1. resets ldisc data fields to their initial state
 2. resets tty->receive_room to indicate more data can be sent
 3. schedules buffer work to receive more data
 4. signals a buffer flush has happened to linked pty in packet mode

Since the ldisc has been halted and the tty may soon be destructed,
buffer work must not be scheduled as that work might access
an invalid tty and ldisc state. Also, the ldisc read buffer is about
to be freed, so that's pointless.

Resetting the ldisc data fields is pointless as well since that
structure is about to be freed.

Resetting tty->receive_room is unnecessary, as it will be properly
reset if a new ldisc is reopened. Besides, resetting the original
receive_room value would be wrong since the read buffer will be
gone.

Since the packet mode flush is observable from userspace, this
behavior has been preserved.

The test jig originally authored by Ilya Zykov <ilya@ilyx.ru> and
signed off by him is included below. The test jig prompts the
following warnings which this patch fixes.

[   38.051111] ------------[ cut here ]------------
[   38.052113] WARNING: at drivers/tty/n_tty.c:160 n_tty_set_room.part.6+0x8b/0xa0()
[   38.053916] Hardware name: Bochs
[   38.054819] Modules linked in: netconsole configfs bnep rfcomm bluetooth parport_pc ppdev snd_hda_intel snd_hda_codec
snd_hwdep snd_pcm snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq psmouse snd_timer serio_raw mac_hid snd_seq_device
snd microcode lp parport virtio_balloon soundcore i2c_piix4 snd_page_alloc floppy 8139too 8139cp
[   38.059704] Pid: 1564, comm: pty_kill Tainted: G        W    3.7.0-next-20121130+ttydebug-xeon #20121130+ttydebug
[   38.061578] Call Trace:
[   38.062491]  [<ffffffff81058b4f>] warn_slowpath_common+0x7f/0xc0
[   38.063448]  [<ffffffff81058baa>] warn_slowpath_null+0x1a/0x20
[   38.064439]  [<ffffffff8142dc2b>] n_tty_set_room.part.6+0x8b/0xa0
[   38.065381]  [<ffffffff8142dc82>] n_tty_set_room+0x42/0x80
[   38.066323]  [<ffffffff8142e6f2>] reset_buffer_flags+0x102/0x160
[   38.077508]  [<ffffffff8142e76d>] n_tty_flush_buffer+0x1d/0x90
[   38.078782]  [<ffffffff81046569>] ? default_spin_lock_flags+0x9/0x10
[   38.079734]  [<ffffffff8142e804>] n_tty_close+0x24/0x60
[   38.080730]  [<ffffffff81431b61>] tty_ldisc_close.isra.2+0x41/0x60
[   38.081680]  [<ffffffff81431bbb>] tty_ldisc_kill+0x3b/0x80
[   38.082618]  [<ffffffff81432a07>] tty_ldisc_release+0x77/0xe0
[   38.083549]  [<ffffffff8142b781>] tty_release+0x451/0x4d0
[   38.084525]  [<ffffffff811950be>] __fput+0xae/0x230
[   38.085472]  [<ffffffff8119524e>] ____fput+0xe/0x10
[   38.086401]  [<ffffffff8107aa88>] task_work_run+0xc8/0xf0
[   38.087334]  [<ffffffff8105ea56>] do_exit+0x196/0x4b0
[   38.088304]  [<ffffffff8106c77b>] ? __dequeue_signal+0x6b/0xb0
[   38.089240]  [<ffffffff8105ef34>] do_group_exit+0x44/0xa0
[   38.090182]  [<ffffffff8106f43d>] get_signal_to_deliver+0x20d/0x4e0
[   38.091125]  [<ffffffff81016979>] do_signal+0x29/0x130
[   38.092096]  [<ffffffff81431a9e>] ? tty_ldisc_deref+0xe/0x10
[   38.093030]  [<ffffffff8142a317>] ? tty_write+0xb7/0xf0
[   38.093976]  [<ffffffff81193f53>] ? vfs_write+0xb3/0x180
[   38.094904]  [<ffffffff81016b20>] do_notify_resume+0x80/0xc0
[   38.095830]  [<ffffffff81700492>] int_signal+0x12/0x17
[   38.096788] ---[ end trace 5f6f7a9651cd999b ]---

[ 2730.570602] ------------[ cut here ]------------
[ 2730.572130] WARNING: at drivers/tty/n_tty.c:160 n_tty_set_room+0x107/0x140()
[ 2730.574904] scheduling buffer work for halted ldisc
[ 2730.578303] Pid: 9691, comm: trinity-child15 Tainted: G        W 3.7.0-rc8-next-20121205-sasha-00023-g59f0d85 #207
[ 2730.588694] Call Trace:
[ 2730.590486]  [<ffffffff81c41d77>] ? n_tty_set_room+0x107/0x140
[ 2730.592559]  [<ffffffff8110c827>] warn_slowpath_common+0x87/0xb0
[ 2730.595317]  [<ffffffff8110c8b1>] warn_slowpath_fmt+0x41/0x50
[ 2730.599186]  [<ffffffff81c41d77>] n_tty_set_room+0x107/0x140
[ 2730.603141]  [<ffffffff81c42fe7>] reset_buffer_flags+0x137/0x150
[ 2730.607166]  [<ffffffff81c43018>] n_tty_flush_buffer+0x18/0x90
[ 2730.610123]  [<ffffffff81c430af>] n_tty_close+0x1f/0x60
[ 2730.612068]  [<ffffffff81c461f2>] tty_ldisc_close.isra.4+0x52/0x60
[ 2730.614078]  [<ffffffff81c462ab>] tty_ldisc_reinit+0x3b/0x70
[ 2730.615891]  [<ffffffff81c46db2>] tty_ldisc_hangup+0x102/0x1e0
[ 2730.617780]  [<ffffffff81c3e537>] __tty_hangup+0x137/0x440
[ 2730.619547]  [<ffffffff81c3e869>] tty_vhangup+0x9/0x10
[ 2730.621266]  [<ffffffff81c48f1c>] pty_close+0x14c/0x160
[ 2730.622952]  [<ffffffff81c3fd45>] tty_release+0xd5/0x490
[ 2730.624674]  [<ffffffff8127fbe2>] __fput+0x122/0x250
[ 2730.626195]  [<ffffffff8127fd19>] ____fput+0x9/0x10
[ 2730.627758]  [<ffffffff81134602>] task_work_run+0xb2/0xf0
[ 2730.629491]  [<ffffffff811139ad>] do_exit+0x36d/0x580
[ 2730.631159]  [<ffffffff81113c8a>] do_group_exit+0x8a/0xc0
[ 2730.632819]  [<ffffffff81127351>] get_signal_to_deliver+0x501/0x5b0
[ 2730.634758]  [<ffffffff8106de34>] do_signal+0x24/0x100
[ 2730.636412]  [<ffffffff81204865>] ? user_exit+0xa5/0xd0
[ 2730.638078]  [<ffffffff81183cd8>] ? trace_hardirqs_on_caller+0x118/0x140
[ 2730.640279]  [<ffffffff81183d0d>] ? trace_hardirqs_on+0xd/0x10
[ 2730.642164]  [<ffffffff8106df78>] do_notify_resume+0x48/0xa0
[ 2730.643966]  [<ffffffff83cdff6a>] int_signal+0x12/0x17
[ 2730.645672] ---[ end trace a40d53149c07fce0 ]---

/*
 * pty_thrash.c
 *
 * Based on original test jig by Ilya Zykov <ilya@ilyx.ru>
 *
 * Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
 * Signed-off-by: Ilya Zykov <ilya@ilyx.ru>
 */

static int fd;

static void error_exit(char *f, ...)
{
        va_list va;

        va_start(va, f);
        vprintf(f, va);
        printf(": %s\n", strerror(errno));
        va_end(va);

        if (fd >= 0)
                close(fd);

        exit(EXIT_FAILURE);
}

int main(int argc, char *argv[]) {
        int parent;
        char pts_name[24];
        int ptn, unlock;

        while (1) {

                fd = open("/dev/ptmx", O_RDWR);
                if (fd < 0)
                        error_exit("opening pty master");
                unlock = 0;
                if (ioctl(fd, TIOCSPTLCK, &unlock) < 0)
                        error_exit("unlocking pty pair");
                if (ioctl(fd, TIOCGPTN, &ptn) < 0)
                        error_exit("getting pty #");
                snprintf(pts_name, sizeof(pts_name), "/dev/pts/%d", ptn);

                child_id = fork();
                if (child_id == -1)
                        error_exit("forking child");

                if (parent) {
                        int err, id, status;
                        char buf[128];
                        int n;

                        n = read(fd, buf, sizeof(buf));
                        if (n < 0)
                                error_exit("master reading");
                        printf("%.*s\n", n-1, buf);

                        close(fd);

                        err = kill(child_id, SIGKILL);
                        if (err < 0)
                                error_exit("killing child");
                        id = waitpid(child_id, &status, 0);
                        if (id < 0 || id != child_id)
                                error_exit("waiting for child");

                } else { /* Child */

                        close(fd);
                        printf("Test cycle on slave pty %s\n", pts_name);
                        fd = open(pts_name, O_RDWR);
                        if (fd < 0)
                                error_exit("opening pty slave");

                        while (1) {
                                char pattern[] = "test\n";
                                if (write(fd, pattern, strlen(pattern)) < 0)
                                        error_exit("slave writing");
                        }

                }
        }

        /* never gets here */
        return 0;
}

Reported-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:32:46 -07:00
Peter Hurley a30737ab7d n_tty: Factor packet mode status change for reuse
Factor the packet mode status change from n_tty_flush_buffer
for use by follow-on patch.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:32:46 -07:00
Peter Hurley 21622939fc tty: Add diagnostic for halted line discipline
Flip buffer work must not be scheduled by the line discipline
after the line discipline has been halted; issue warning.

Note: drivers can still schedule flip buffer work.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:32:46 -07:00
Lars-Peter Clausen 91debb0383 tty: ifx6x60: Remove unused suspend/resume callbacks
The ifx6x60 driver implements both legacy suspend/resume callbacks and
dev_pm_ops. The SPI core is going to ignore legacy suspend/resume
callbacks if a driver implements dev_pm_ops. Since the legacy suspend/resume
callbacks are empty in this case it is safe to just remove them.

Cc: Bi Chao <chao.bi@intel.com>
Cc: Chen Jun <jun.d.chen@intel.com>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:29:29 -07:00
Lars-Peter Clausen c2ee91bd66 tty: mrst_max3110: Use dev_pm_ops
Use dev_pm_ops instead of the deprecated legacy suspend/resume for the
mrst_max3110 driver.

Cc: Alan Cox <alan@linux.intel.com>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:29:29 -07:00
Lars-Peter Clausen b7df719db7 tty: max310x: Use dev_pm_ops
Use dev_pm_ops instead of the deprecated legacy suspend/resume for the
max310x driver.

Cc: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:29:29 -07:00
Lars-Peter Clausen c47ddc26db tty: max3100: Use dev_pm_ops
Use dev_pm_ops instead of the deprecated legacy suspend/resume for the
max3100 driver.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:29:29 -07:00
Johan Hovold 0b2588cadf TTY: fix close of uninitialised ports
Make sure we do not make tty-driver callbacks or wait for port to drain
on uninitialised ports (e.g. when open failed) in
tty_port_close_start().

No callback, such as flush_buffer or wait_until_sent, needs to be made
on a port that has never been opened. Neither does it make much sense to
add drain delay for an uninitialised port.

Currently a drain delay of up to two seconds could be added when a tty
fails to open.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:27:54 -07:00
Johan Hovold b74414f5f3 TTY: clean up port drain-delay handling
Move port drain-delay handling to a separate function.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:27:54 -07:00
Johan Hovold 957dacaee5 TTY: fix DTR not being dropped on hang up
Move HUPCL handling to port shutdown so that DTR is dropped also on hang
up (tty_port_close is a noop for hung-up ports).

Also do not try to drop DTR for uninitialised ports where it has never
been raised (e.g. after a failed open).

Note that this is also the current behaviour of serial-core.

Nine drivers currently call tty_port_close_start directly (rather than
through tty_port_close) and seven of them lower DTR as part of their
close (if the port has been initialised). Fixup the remaining two
drivers so that it continues to be lowered also on normal (non-HUP)
close. [ Note that most of those other seven drivers did not expect DTR
to have been dropped by tty_port_close_start in the first place. ]

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:27:53 -07:00
Johan Hovold e584a02cf5 TTY: fix DTR being raised on hang up
Make sure to check ASYNC_INITIALISED before raising DTR when waking up
from blocked open in tty_port_block_til_ready.

Currently DTR could get raised at hang up as a blocked process would
raise DTR unconditionally before checking for hang up and returning.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:27:53 -07:00
Johan Hovold 31ca020b57 TTY: wake up processes last at hangup
Move wake up of processes on blocked-open and modem-status wait queues
to after port shutdown at hangup.

This way the woken up processes can use the ASYNC_INITIALIZED flag to
detect port shutdown.

Note that this is the order currently used by serial-core.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:27:53 -07:00
Johan Hovold 8bde9658a0 TTY: clean up port shutdown
Untangle port-shutdown logic and make sure the initialised flag is
always cleared for non-console ports.

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:27:53 -07:00
Jiri Slaby b12d8dc2db crisv10: use counts from tty_port
The same as flags, convert to using open/close counts from tty_port.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:26:33 -07:00
Jiri Slaby 4aeaeb0c39 crisv10: use *_wait from tty_port
The same as flags, convert to using *_wait queues from tty_port.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:26:32 -07:00
Jiri Slaby 892c7cfc16 crisv10: use close delays from tty_port
The same as flags, convert to using close delays from tty_port.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:26:32 -07:00
Jiri Slaby 82c3b87b7e crisv10: remove unused members
Well, all those are unused. They were perhaps copied from generic
serial structure ages ago. Remove them for good.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:26:25 -07:00
Jiri Slaby 12aad550f0 crisv10: stop returning info from handle_ser_rx_interrupt
The return value is not used anywhere, so no need to return anything.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:26:01 -07:00
Jiri Slaby b1d984cf7d crisv10: use flags from tty_port
First, remove STD_FLAGS as the value, or its subvalues
(ASYNC_BOOT_AUTOCONF | ASYNC_SKIP_TEST) is not tested anywhere --
there is no point to initialize flags to that. Second, use flags
member from tty_port when we have it now. So that we do not waste
space.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:25:29 -07:00
Jiri Slaby ee79706905 TTY: cleanup tty->hw_stopped uses
tty->hw_stopped is set only by drivers to remember HW state. If it is
never set to 1 in a particular driver, there is no need to check it in
the driver at all. Remove such checks.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:24:30 -07:00
Jiri Slaby 4d29994ddb TTY: serial/msm_serial_hs, remove unused tty
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:24:30 -07:00
Jiri Slaby e99c33b9d3 TTY: serial/bfin_uart, unbreak build with KGDB enabled
There are no (and never were any) kgdb fields in uart_ops. Setting
them produces a build error:
drivers/tty/serial/bfin_uart.c:1054:2: error: unknown field 'kgdboc_port_startup' specified in initializer
drivers/tty/serial/bfin_uart.c:1054:2: warning: initialization from incompatible pointer type [enabled by default]
drivers/tty/serial/bfin_uart.c:1054:2: warning: (near initialization for 'bfin_serial_pops.ioctl') [enabled by default]
drivers/tty/serial/bfin_uart.c:1055:2: error: unknown field 'kgdboc_port_shutdown' specified in initializer
drivers/tty/serial/bfin_uart.c:1055:2: warning: initialization from incompatible pointer type [enabled by default]
drivers/tty/serial/bfin_uart.c:1055:2: warning: (near initialization for 'bfin_serial_pops.poll_init') [enabled by default]

Remove them.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:24:30 -07:00
Jiri Slaby aa27a094e2 TTY: add tty_port_tty_hangup helper
It allows for cleaning up on a considerable amount of places. They did
port_get, hangup, kref_put. Now the only thing needed is to call
tty_port_tty_hangup which does exactly that. And they can also decide
whether to consider CLOCAL or completely ignore that.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:24:29 -07:00
Jiri Slaby e4408ce3c2 TTY: quatech2, remove unneeded is_open
tty->ops->break_ctl cannot be called outside the gap between open and
close. So there is no need to check whether the port is open in
break_ctl in quatech2. Remove the check and also that member
completely.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Bill Pemberton <wfp5p@virginia.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:21:26 -07:00
Jiri Slaby 6aad04f213 TTY: add tty_port_tty_wakeup helper
It allows for cleaning up on a considerable amount of places. They did
port_get, wakeup, kref_put. Now the only thing needed is to call
tty_port_tty_wakeup which does exactly that.

One exception is ifx6x60 where tty_wakeup was open-coded. We now call
tty_wakeup properly there.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:19:45 -07:00
Jiri Slaby 6982a39842 TTY: msm_smd_tty, clean up activate/shutdown
Do not dig struct smd_tty_info out of tty_struct using
tty_port_tty_get. It is unnecessarily too complicated, use simple
container_of instead.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:19:44 -07:00
Jiri Slaby 6865ff222c TTY: do not warn about setting speed via SPD_*
The warning is there since 2.1.69 and we have not seen anybody
reporting it in the past decade. Remove the warning now.

tty_get_baud_rate can now be inline. This gives us one less
EXPORT_SYMBOL.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:19:05 -07:00
Jiri Slaby 049b539b39 TTY: synclink, remove superfluous check
info is obtained by container_of. It can never be NULL. So do not test
that.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:17:20 -07:00
Jiri Slaby b1622e0ac1 TTY: jsm, remove superfluous check
data_len in jsm_input cannot be zero as we would jump out early in the
function. It also cannot be negative because it is an int and we do
bitwise and with 8192. So remove the check.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Lucas Tavares <lucaskt@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:17:20 -07:00
Peter Hurley 6be06e7273 tty: Fix checkpatch errors in tty_ldisc.h
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:14:55 -07:00
Peter Hurley 01a5e440c9 n_tty: Lock access to tty->pgrp for POSIX job control
Concurrent access to tty->pgrp must be protected with tty->ctrl_lock.
Also, as noted in the comments, reading current->signal->tty is
safe because either,
  1) current->signal->tty is assigned by current, or
  2) current->signal->tty is set to NULL.

NB: for reference, tty_check_change() implements a similar POSIX
check for the ioctls corresponding to tcflush(), tcdrain(),
tcsetattr(), tcsetpgrp(), tcflow() and tcsendbreak().

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:13:59 -07:00
Peter Hurley 8c985d18b1 n_tty: Fix unsafe driver-side signals
An ldisc reference is insufficient guarantee the foreground process
group is not in the process of being signalled from a hangup.

1) Reads of tty->pgrp must be locked with ctrl_lock
2) The group pid must be referenced for the duration of signalling.
   Because the driver-side is not process-context, a pid reference
   must be acquired.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:13:59 -07:00
Peter Hurley e91e52e428 n_tty: Fix stuck throttled driver
As noted in the following comment:

  /* FIXME: there is a tiny race here if the receive room check runs
     before the other work executes and empties the buffer (upping
     the receiving room and unthrottling. We then throttle and get
     stuck. This has been observed and traced down by Vincent Pillet/
     We need to address this when we sort out out the rx path locking */

Use new safe throttle/unthrottle functions to re-evaluate conditions
if interrupted by the complement flow control function.

Reported-by: Vincent Pillet <vincentx.pillet@intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:11:59 -07:00
Peter Hurley 70bc126471 tty: Add safe tty throttle/unthrottle functions
The tty driver can become stuck throttled due to race conditions
between throttle and unthrottle, when the decision to throttle
or unthrottle is conditional. The following example helps to
illustrate the race:

  CPU 0                        |  CPU 1
                               |
if (condition A)               |
                               | <processing such that A not true>
                               | if (!condition A)
                               |     unthrottle()
    throttle()                 |
                               |

Note the converse is also possible; ie.,

  CPU 0                        |  CPU 1
                               |
                               | if (!condition A)
<processing such that A true>  |
if (condition A)               |
    throttle()                 |
                               |     unthrottle()
                               |

Add new throttle/unthrottle functions based on the familiar model
of task state and schedule/wake. For example,

    while (1) {
        tty_set_flow_change(tty, TTY_THROTTLE_SAFE);
        if (!condition)
            break;
        if (!tty_throttle_safe(tty))
            break;
    }
    __tty_set_flow_change(tty, 0);

In this example, if an unthrottle occurs after the condition is
evaluated but before tty_throttle_safe(), then tty_throttle_safe()
will return non-zero, looping and forcing the re-evaluation of
condition.

Reported-by: Vincent Pillet <vincentx.pillet@intel.com>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:11:59 -07:00
Peter Hurley c828f679ee n_tty: Inline check_unthrottle() at lone call site
2-line function check_unthrottle() is now only called from
n_tty_read(); merge into caller.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-18 16:11:59 -07:00
zhangwei(Jovi) afa80ccb4c sysrq: fix inconstistent help message of sysrq key
Currently help message of /proc/sysrq-trigger highlight its
upper-case characters, like below:

      SysRq : HELP : loglevel(0-9) reBoot Crash terminate-all-tasks(E)
      memory-full-oom-kill(F) kill-all-tasks(I) ...

this would confuse user trigger sysrq by upper-case character, which is
inconsistent with the real lower-case character registed key.

This inconsistent help message will also lead more confused when
26 upper-case letters put into use in future.

This patch fix it.

Thanks the comments from Andrew and Randy.

Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@huawei.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-03-15 14:06:45 -07:00