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2016-01-28tty: Remove ASYNC_CLOSINGPeter Hurley7-14/+5
The tty core no longer provides nor uses ASYNC_CLOSING; remove from tty_port_close_start() and tty_port_close_end() as well as tty drivers which open-code these state changes. Unfortunately, even though the bit is masked from userspace, its inclusion in a uapi header precludes removing the macro. Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: linux-s390@vger.kernel.org Cc: Mikael Starvik <starvik@axis.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: linux-cris-kernel@axis.com Cc: Samuel Ortiz <samuel@sortiz.org> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28isdn: Remove ASYNC_CLOSINGPeter Hurley2-6/+7
The tty core no longer provides ASYNC_CLOSING. Use private flag for same purpose, which is to disable AT-emulator output (why this is necessary is not clear). Cc: Karsten Keil <isdn@linux-pingi.de> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28tty: mxser: Remove ASYNC_CLOSINGPeter Hurley1-4/+5
The tty core no longer provides ASYNC_CLOSING. Use private flag for same purpose, which is to clear the fifos at each and every interrupt during driver close(). The driver uses this sledgehammer approach because its close/shutdown sequence is hopelessly borked. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28serial: core: Perform RTS signalling before soft flow ctrlPeter Hurley1-6/+6
When throttling, time is of the essence; try RTS signalling before soft flow control, which will take longer. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28serial: core: Unfold < 80 char linesPeter Hurley1-10/+5
Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28serial: core: Remove cast from void ptr in uart_open()Peter Hurley1-1/+1
void * promotes to any pointer type; remove type cast. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28serial: core: Cleanup uart_open() exitPeter Hurley1-4/+1
If aborting uart_open() unsuccessfully, retval is non-zero, so the existing fall-through exit is equivalent. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28serial: Fix ASYNC_* => UPF_* flags misusePeter Hurley7-17/+17
The UPF_* flags are the correct values to use for struct uart_port and struct old_serial_port/SERIAL_PORT_DFNS. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28serial: core: Use tty->index for port # in debug messagesPeter Hurley1-3/+2
The uart port may have already been removed by uart_remove_one_port(); use equivalent tty->index (which is always valid in these contexts) instead. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28serial: core: Fold do_uart_get_info() into callerPeter Hurley1-11/+7
do_uart_get_info() has a single caller: uart_get_info(). Manually inline do_uart_get_info(). Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28serial: core: Fold __uart_put_char() into callerPeter Hurley1-9/+5
uart_put_char() is the required interface; manually inline __uart_put_char(). Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28tty: Use termios c_*flag macrosPeter Hurley28-161/+113
Expressions of the form "tty->termios.c_*flag & FLAG" are more clearly expressed with the termios flags macros, I_FLAG(), C_FLAG(), O_FLAG(), and L_FLAG(). Convert treewide. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Acked-by: Johan Hovold <johan@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28tty: Allow unreadable mess to be > 80 charsPeter Hurley1-4/+2
Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28tty: Unify receive_buf() code pathsPeter Hurley2-25/+30
Instead of two distinct code branches for receive_buf() handling, use tty_ldisc_receive_buf() as the single code path. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28tty: Fix GPF in flush_to_ldisc(), part 2Peter Hurley1-1/+1
commit 9ce119f318ba ("tty: Fix GPF in flush_to_ldisc()") fixed a GPF caused by a line discipline which does not define a receive_buf() method. However, the vt driver (and speakup driver also) pushes selection data directly to the line discipline receive_buf() method via tty_ldisc_receive_buf(). Fix the same problem in tty_ldisc_receive_buf(). Cc: <stable@vger.kernel.org> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28staging: dgap: Remove redundant write_wait wakeupsPeter Hurley1-6/+0
Waking the write_wait queue is exactly what tty_wakeup() does; remove the open-coded wakeups. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28ia64: Pin controlling tty for unaligned fault messagePeter Hurley1-2/+5
Prevent destruction of the controlling tty before tty_write_message() can determine if the tty is safe to use. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28n_tty: Ignore all read data when closingPeter Hurley1-2/+0
On final port close (and thus final tty close), only output flow control requests in the input data should be processed. Ignore all other input data, including parity errors, overruns and breaks. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28tty: rocket: Remove private close_waitPeter Hurley2-3/+0
This driver's private completion variable, close_wait, is no longer used for wait since "tty: Remove ASYNC_CLOSING checks in open()/hangup"; remove. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28serial: 8250: Unfold < 80 char linesPeter Hurley1-7/+4
Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28serial: 8250: Wait for irq to complete before shutdownPeter Hurley1-0/+4
After masking all interrupts, wait for the irq handler to complete before continuing shutdown. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28serial: 8250: Unlink uart console ptr if console setup failsPeter Hurley1-1/+5
If console setup fails (eg., there is no valid port at that index), unlink the console ptr; otherwise, when the driver unloads, the console will be unregistered (even though setup, and thus registration, failed) and a console disabled message will be printed. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28serial: 8250: Remove low_latency workaroundPeter Hurley1-2/+1
The defunct low_latency input steering executed flush_to_ldisc() directly from interrupt context so dropping the port lock was necessary to avoid deadlock. That steering was removed by commit a9c3f68f3cd8d55f809fbdb0c138ed061ea1bd25 Author: Peter Hurley <peter@hurleysoftware.com> Date: Sat Feb 22 07:31:21 2014 -0500 tty: Fix low_latency BUG Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28serial: 8250: Fix lost rx statePeter Hurley1-3/+4
When max_count is reached, the rx loop exits. However, UART_LSR has already been read so those char flags are lost, and subsequent rx status will be for the wrong byte until the rx fifo drains. Reported-by: George Spelvin <linux@horizon.com> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28serial: 8250: Refactor serial8250_rx_chars() inner loopPeter Hurley1-58/+62
Factor the read/process one char inner loop to a separate helper function serial8250_read_char(). No functional change. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28tty: n_tty: fix SIGIO for outputPeter Hurley1-1/+1
According to fcntl(2), "a SIGIO signal is sent whenever input or output becomes possible on that file descriptor", i.e. after the output buffer was full and now has space for new data. But in fact SIGIO is sent after every write. n_tty_write() should set TTY_DO_WRITE_WAKEUP only when not all data could be written to the buffer. [pjh: Also fixes missed SIGIO if amt written just happens to be [ amount still to write Signed-off-by: Johannes Stezenbach <js@sig21.net> [pjh: minor patch edits and re-submit] Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28n_tty: Remove tty count checks from unthrottlePeter Hurley1-4/+0
Since n_tty_check_unthrottle() is only called from n_tty_read() which only originates from a userspace read(), the tty count cannot be 0; the read() guarantees the file descriptor has not yet been released. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28n_tty: Fix stuck write wakeupPeter Hurley1-2/+2
If signal-driven i/o is disabled while write wakeup is pending (ie., n_tty_write() has set TTY_DO_WRITE_WAKEUP but then signal-driven i/o is disabled), the TTY_DO_WRITE_WAKEUP bit will never be cleared and will cause tty_wakeup() to always call n_tty_write_wakeup. Unconditionally clear the write wakeup, and since kill_fasync() already checks if the fasync ptr is null, call kill_fasync() unconditionally as well. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28tty: Fix ioctl(FIOASYNC) on hungup filePeter Hurley1-2/+3
A small race window exists which allows signal-driven async i/o to be enabled for the tty when the file ptr has already been hungup and signal-driven i/o has been disabled: CPU 0 CPU 1 ----- ------ ioctl_fioasync(on) filp->f_op->fasync(on) __tty_hangup() tty_fasync(on) tty_lock() tty_lock() ... . filp->f_op = &hung_up_tty_fops; (waiting) __tty_fasync(off) . tty_unlock() /* gets tty lock */ /* enables FASYNC */ Check the tty has not been hungup while holding tty_lock. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28tty: Add fasync() hung up file operationPeter Hurley1-0/+6
VFS uses a two-stage check-and-call method for invoking file_operations methods, without explicitly snapshotting either the file_operations ptr or the function ptr. Since the tty core is one of the few VFS users that changes the f_op file_operations ptr of the file descriptor (when the tty has been hung up), and since the likelihood of the compiler generating a reload of either f_op or the function ptr is basically nil, just define a hung up fasync() file operation that returns an error. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28tty, n_tty: Remove fasync() ldisc notificationPeter Hurley3-19/+0
Only the N_TTY line discipline implements the signal-driven i/o notification enabled/disabled by fcntl(F_SETFL, O_ASYNC). The ldisc fasync() notification is sent to the ldisc when the enable state has changed (the tty core is notified via the fasync() VFS file operation). The N_TTY line discipline used the enable state to change the wakeup condition (minimum_to_wake = 1) for notifying the signal handler i/o is available. However, just the presence of data is sufficient and necessary to signal i/o is available, so changing minimum_to_wake is unnecessary (and creates a race condition with read() and poll() which may be concurrently updating minimum_to_wake). Furthermore, since the kill_fasync() VFS helper performs no action if the fasync list is empty, calling unconditionally is preferred; if signal driven i/o just has been disabled, no signal will be sent by kill_fasync() anyway so notification of the change via the ldisc fasync() method is superfluous. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-28n_tty: Always wake up read()/poll() if new inputPeter Hurley1-32/+2
A read() in non-canonical mode when VMIN > 0 and VTIME == 0 does not complete until at least VMIN chars have been read (or the user buffer is full). In this infrequent read mode, n_tty_read() attempts to reduce wakeups by computing the amount of data still necessary to complete the read (minimum_to_wake) and only waking the read()/poll() when that much unread data has been processed. This is the only read mode for which new data does not necessarily generate a wakeup. However, this optimization is broken and commonly leads to hung reads even though the necessary amount of data has been received. Since the optimization is of marginal value anyway, just remove the whole thing. This also remedies a race between a concurrent poll() and read() in this mode, where the poll() can reset the minimum_to_wake of the read() (and vice versa). Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-27tty: audit: Poison tty_audit_buf while process exitsPeter Hurley1-8/+17
Warn if tty_audit_buf use is attempted after tty_audit_exit() has already freed it. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-27tty: audit: Always push audit buffer before TIOCSTIPeter Hurley1-9/+3
The data read from another tty may be relevant to the action of the TIOCSTI ioctl; log the audit buffer immediately. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-27tty: audit: Check audit enable firstPeter Hurley1-3/+4
Audit is unlikely to be enabled; check first to exit asap. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-27tty: audit: Simplify first-use allocationPeter Hurley1-15/+7
The first-use tty audit buffer allocation is a potential race amongst multiple attempts at 'first-use'; only one 'winner' is acceptable. The successful buffer assignment occurs if tty_audit_buf == NULL (which will also be the return from cmpxchg()); otherwise, another racer 'won' and this buffer allocation is freed. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-27tty: audit: Remove tty_audit_buf reference countingPeter Hurley1-40/+7
When tty_audit_exit() is called from do_exit(), the process is single-threaded. Since the tty_audit_buf is only shared by threads of a process, no other thread can be concurrently accessing the tty_audit_buf during or after tty_audit_exit(). Thus, no other thread can be holding an extra tty_audit_buf reference which would prevent tty_audit_exit() from freeing the tty_audit_buf. As that is the only purpose of the ref counting, remove the reference counting and free the tty_audit_buf directly. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-27tty: audit: Remove false memory optimizationPeter Hurley1-5/+1
The tty audit buffer is allocated at first use and not freed until the process exits. If tty audit is turned off after the audit buffer has been allocated, no effort is made to release the buffer. So re-checking if tty audit has just been turned off when tty audit was just on is false optimization; the likelihood of triggering this condition is exceedingly small. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-27tty: audit: Handle tty audit enable atomicallyPeter Hurley4-45/+38
The audit_tty and audit_tty_log_passwd fields are actually bool values, so merge into single memory location to access atomically. NB: audit log operations may still occur after tty audit is disabled which is consistent with the existing functionality Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-27tty: audit: Track tty association with dev_tPeter Hurley1-18/+14
Use dev_t instead of separate major/minor fields to track tty audit buffer association. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-27tty: audit: Combine push functionsPeter Hurley3-39/+6
tty_audit_push() and tty_audit_push_current() perform identical tasks; eliminate the tty_audit_push() implementation and the tty_audit_push_current() name. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-27tty: audit: Ignore current association for audit pushPeter Hurley3-11/+6
In canonical read mode, each line read and logged is pushed separately with tty_audit_push(). For all single-threaded processes and multi-threaded processes reading from only one tty, this patch has no effect; the last line read will still be the entry pushed to the audit log because the tty association cannot have changed between tty_audit_add_data() and tty_audit_push(). For multi-threaded processes reading from different ttys concurrently, the audit log will have mixed log entries anyway. Consider two ttys audited concurrently: CPU0 CPU1 ---------- ------------ tty_audit_add_data(ttyA) tty_audit_add_data(ttyB) tty_audit_push() tty_audit_add_data(ttyB) tty_audit_push() This patch will now cause the ttyB output to be split into separate audit log entries. However, this possibility is equally likely without this patch: CPU0 CPU1 ---------- ------------ tty_audit_add_data(ttyB) tty_audit_add_data(ttyA) tty_audit_push() tty_audit_add_data(ttyB) tty_audit_push() Mixed canonical and non-canonical reads have similar races. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-27tty: audit: Take siglock directlyPeter Hurley1-8/+5
lock_task_sighand() is for situations where the struct task_struct* may disappear while trying to deref the sighand; this never applies to 'current'. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-27tty: audit: Defer audit buffer associationPeter Hurley1-8/+8
The tty audit buffer used to audit/record tty input is allocated on the process's first call to tty_audit_add_data(), and not freed until the process exits. On each call to tty_audit_add_data(), the current tty is compared (by major:minor) with the last tty associated with the audit buffer, and if the tty has changed the existing data is logged to the audit log. The audit buffer is then re-associated with the new tty. Currently, the audit buffer is immediately associated with the tty; however, the association must be re-checked when the buffer is locked prior to copying the tty input. This extra step is always necessary, since a concurrent read of a different tty by another thread of the process may have used the buffer in between allocation and buffer lock. Rather than associate the audit buffer with the tty at allocation, leave the buffer initially un-associated (null dev_t); simply let the re-association check also perform the initial association. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-27tty: audit: Remove icanon mode from call chainPeter Hurley3-18/+14
The tty termios bits cannot change while n_tty_read() is in the i/o loop; the termios_rwsem ensures mutual exclusion with termios changes in n_tty_set_termios(). Check L_ICANON() directly and eliminate icanon parameter. NB: tty_audit_add_data() => tty_audit_buf_get() => tty_audit_buf_alloc() is a single path; ie., tty_audit_buf_get() and tty_audit_buf_alloc() have no other callers. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-27tty: audit: Never audit packet modePeter Hurley1-13/+4
tty audit never logs pty master reads, but packet mode only works for pty masters, so tty_audit_add_data() was never logging packet mode anyway. Don't audit packet mode data. As those are the lone call sites, remove tty_put_user(). Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-27tty: audit: Early-out pty master reads earlierPeter Hurley1-4/+4
Reads from pty masters are not logged; early-out before taking locks. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-27tty: Make tty_files_lock per-ttyPeter Hurley3-16/+15
Access to tty->tty_files list is always per-tty, never for all ttys simultaneously. Replace global tty_files_lock spinlock with per-tty ->files_lock. Initialize when the ->tty_files list is inited, in alloc_tty_struct(). Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-27tty: Remove unreferenced tty flags macro TTY_DEBUGPeter Hurley1-1/+0
The TTY_DEBUG macro is not used; remove. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-01-27tty: Move tty_check_change() helperPeter Hurley3-7/+6
Move is_ignored() to drivers/tty/tty_io.c and re-declare in file scope. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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