Andreas Platschek [Fri, 26 Jul 2013 04:46:37 +0000 (06:46 +0200)]
tty: Remove dead code
-> The ledptrs[] array is never initialized.
-> There is no place where kbd->ledmode is set to LED_SHOW_MEM therefore the if
statement does not make much sense.
-> Since LED_SHOW_MEM is not used, it can be removed from the header file as well.
Signed-off-by: Andreas Platschek <andi.platschek@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stephen Boyd [Wed, 24 Jul 2013 18:37:31 +0000 (11:37 -0700)]
msm_serial: Send more than 1 character at a time on UARTDM
UARTDM cores have a TX fifo that can accept more than one
character per register write, but the msm_serial driver currently
only supports 1 character mode. Add support for this mode of operation
to speed up the transmit path on DM devices.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: David Brown <davidb@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stephen Boyd [Wed, 24 Jul 2013 18:37:30 +0000 (11:37 -0700)]
msm_serial: Make baud_code detection more dynamic
Currently msm_set_baud_rate() assumes the uart clock rate is
1.8432 MHz. This is not always true, and limits our options to
program the baud rate. Instead of assuming the rate and
hard-coding the baud_code based on it, calculate the divider that
we want and try to find the closest baud_code that matches. This
allows us to support uarts with faster clock speeds.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: David Brown <davidb@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stephen Boyd [Wed, 24 Jul 2013 18:37:29 +0000 (11:37 -0700)]
msm_serial: Fix sparse warnings
drivers/tty/serial/msm_serial.c:302:6: warning: symbol 'msm_set_mctrl' was
not declared. Should it be static?
drivers/tty/serial/msm_serial.c:597:17: warning: incorrect type in argument 2
(different address spaces)
drivers/tty/serial/msm_serial.c:597:17: expected void volatile [noderef] <asn:2>*addr
drivers/tty/serial/msm_serial.c:597:17: got unsigned int *
drivers/tty/serial/msm_serial.c:608:33: warning: incorrect type in argument 1
(different address spaces)
drivers/tty/serial/msm_serial.c:608:33: expected void volatile [noderef] <asn:2>*addr
drivers/tty/serial/msm_serial.c:608:33: got unsigned int *gsbi_base
drivers/tty/serial/msm_serial.c:648:37: warning: incorrect type in assignment
(different address spaces)
drivers/tty/serial/msm_serial.c:648:37: expected unsigned int *gsbi_base
drivers/tty/serial/msm_serial.c:648:37: got void [noderef] <asn:2>*
Mark the ioremapped memory as __iomem and use writel instead of
iowrite because we're not dealing with PCI devices. Also, mark
msm_set_mctrl() static because it isn't used outside this file.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: David Brown <davidb@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stephen Boyd [Wed, 24 Jul 2013 18:37:28 +0000 (11:37 -0700)]
msm_serial: Fix NUL byte output on UARTDM
UARTDM serial devices require us to wait for the entire TX fifo
to drain before we can change the contents of the NCF_TX
register. Furthermore, if we write any characters to the TX fifo
within the same clock cycle of changing the NCF_TX register the
NCF_TX register won't latch properly.
To fix these issues we should read back the NCF_TX register to
delay any TX fifo accesses by a clock cycle and we should wait
for the TX fifo to drain (instead of just waiting for the fifo to
be ready to receive more characters). Failure to do so leads to
random NUL bytes interspersed in the output.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: David Brown <davidb@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Ian Abbott [Tue, 16 Jul 2013 15:14:41 +0000 (16:14 +0100)]
pci_ids.h: remove PCI_VENDOR_ID_ADDIDATA_OLD and PCI_DEVICE_ID_ADDIDATA_APCI7800
These two defines are no longer used. They were only used by the PCI
serial driver "8250_pci" to support the original ADDI-DATA APCI-7800
card. In that driver, PCI_VENDOR_ID_ADDIDATA_OLD has been replaced with
PCI_VENDOR_ID_AMCC which has the same value (0x10e8), and
PCI_DEVICE_ID_ADDIDATA_APCI7800 has been replaced with a local #define
PCI_DEVICE_ID_AMCC_ADDIDATA_APCI7800 with the same value (0x818e).
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Ian Abbott [Tue, 16 Jul 2013 15:14:40 +0000 (16:14 +0100)]
serial: 8250_pci: use local device ID for ADDI-DATA APCI-7800
The quirks and PCI ID table entries for the original ADDI-DATA APCI-7800
(not the newer APCI-7800-3) use PCI_DEVICE_ID_ADDIDATA_APCI7800 from
<linux/pci_ids.h> but the device ID was actually assigned to ADDI-DATA
by Applied Micro Circuits Corporation (PCI_VENDOR_ID_AMCC). Replace it
locally with #define PCI_DEVICE_ID_AMCC_ADDIDATA_APCI7800.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Ian Abbott [Tue, 16 Jul 2013 15:14:39 +0000 (16:14 +0100)]
serial: 8250_pci: replace PCI_VENDOR_ID_ADDIDATA_OLD
PCI_VENDOR_ID_ADDIDATA_OLD has the same value (0x10e8) as
PCI_VENDOR_ID_AMCC in <linux/pci_ids.h>. The vender ID is actually
assigned to Applied Micro Circuits Corporation. The 8250_pci driver
uses PCI_VENDOR_ID_ADDIDATA_OLD in the lists of quirks and PCI IDs for
the ADDI-DATA APCI-7800 card. Change it to use the more accurate
PCI_VENDOR_ID_AMCC.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Ian Abbott [Tue, 16 Jul 2013 15:14:38 +0000 (16:14 +0100)]
pci_ids.h: move PCI_VENDOR_ID_AMCC here
PCI_VENDOR_ID_AMCC is defined locally in
"drivers/staging/comedi/comedidev.h" for a few comedi hardware drivers,
namely "adl_pci9118", "addi_apci_1500" and "addi_apci_3120" (also
"addi_apci_1710" but that is not currently built and will probably be
removed soon). Move the define into "include/linux/pci_ids.h" as it is
shared by several drivers (albeit all comedi drivers currently).
PCI_VENDOR_ID_AMCC happens to have the same value (0x10e8) as
PCI_VENDOR_ID_ADDIDATA_OLD. The vendor ID is actually assigned to
Applied Micro Circuits Corporation and Addi-Data were using device IDs
assigned by AMCC on some of their earlier PCI boards. The
PCI_VENDOR_ID_ADDIDATA_OLD define is still being used by the "8250_pci"
PCI serial board driver.
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Srinivas Kandagatla [Mon, 15 Jul 2013 11:39:23 +0000 (12:39 +0100)]
serial:st-asc: Add ST ASC driver.
This patch adds support to ASC (asynchronous serial controller)
driver, which is basically a standard serial driver. This IP is common
across all the ST parts for settop box platforms.
ASC is embedded in ST COMMS IP block. It supports Rx & Tx functionality.
It support all industry standard baud rates.
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@st.com>
CC: Stephen Gallimore <stephen.gallimore@st.com>
CC: Stuart Menefy <stuart.menefy@st.com>
CC: Arnd Bergmann <arnd@arndb.de>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Uwe Kleine-König [Thu, 18 Jul 2013 12:51:04 +0000 (14:51 +0200)]
serial/efm32-uart: make of_device_id array const
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Uwe Kleine-König [Wed, 17 Jul 2013 06:48:41 +0000 (08:48 +0200)]
serial/efm32-uart: use COMPILE_TEST symbol to extend compile test coverage
The driver fails to build on x86 because writel_relaxed isn't available
there. That function exists on arm, arm64, avr32, hexagon, mips and sh,
but adding all these is overkill so stick to arm only.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Wei Yongjun [Wed, 17 Jul 2013 05:34:09 +0000 (13:34 +0800)]
msm_serial: add missing iounmap() on error in msm_request_port()
Add the missing iounmap() before return from msm_request_port()
in the error handling case.
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Reviewed-by: Ivan T. Ivanov <iivanov@mm-sol.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Axel Lin [Mon, 15 Jul 2013 05:36:03 +0000 (13:36 +0800)]
serial: bfin_uart: Remove redundant testing for ifdef CONFIG_SERIAL_BFIN_MODULE
No idea why we have redundant testing for ifdef CONFIG_SERIAL_BFIN_MODULE,
check it once is enough.
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Darren Hart [Sat, 13 Jul 2013 00:58:05 +0000 (17:58 -0700)]
pch_uart: Use DMI interface for board detection
Use the DMI interface rather than manually matching DMI strings.
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
Cc: Michael Brunner <mibru@gmx.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Kees Cook [Fri, 12 Jul 2013 20:07:39 +0000 (13:07 -0700)]
serial: report base_baud after initialization
Some serial ports will not use the standard base baud rate. Report
this after initialization so it might be discovered and used for early
console configuration.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Grygorii Strashko [Mon, 22 Jul 2013 10:01:15 +0000 (15:31 +0530)]
serial: omap: enable PM runtime only when its fully configured
If earlyprintk is enabled and current UART is console port the platform
code can mark it as RPM_ACTIVE to sync real IP state with PM Runtime and
avoid resuming of already active device, but now, driver initialization
will be performed in the wrong way:
pm_runtime_enable(&pdev->dev);
<-- PM runtime alowed (device state RPM_ACTIVE)
if (omap_up_info->autosuspend_timeout == 0)
omap_up_info->autosuspend_timeout = -1;
device_init_wakeup(up->dev, true);
pm_runtime_use_autosuspend(&pdev->dev);
<-- update_autosuspend() will be called and it will disable device
(device state RPM_SUSPENDED)
pm_runtime_set_autosuspend_delay(&pdev->dev,
omap_up_info->autosuspend_timeout);
<-- update_autosuspend() will be called which will re-enable device
(device state RPM_ACTIVE), because autosuspend_timeout < 0
pm_runtime_irq_safe(&pdev->dev);
pm_runtime_get_sync(&pdev->dev);
<-- will do nothing
Such behavior isn't expected by OMAP serial drivers and causes
unpredictable calls of serial_omap_runtime_suspend() and
serial_omap_runtime_resume().
Hence, fix it by allowing PM runtime only after all its parameters are
configured.
CC: Tony Lindgren <tony@atomide.com>
CC: Rajendra Nayak <rnayak@ti.com>
CC: Felipe Balbi <balbi@ti.com>
CC: Kevin Hilman <khilman@linaro.org>
Tested-by: Mark Jackson <mpfj-list@newflow.co.uk>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Axel Lin [Mon, 22 Jul 2013 01:12:36 +0000 (09:12 +0800)]
serial: fsl_lpuart: Return proper error on lpuart_serial_init error path
Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Shawn Guo [Mon, 8 Jul 2013 07:53:38 +0000 (15:53 +0800)]
serial: fsl_lpuart: restore UARTCR2 after watermark setup is done
Function lpuart_setup_watermark() clears some bits in register UARTCR2
before writing FIFO configuration registers as required by hardware.
But it should restore UARTCR2 after that. Otherwise, we end up changing
UARTCR2 register when setting up watermark, and that is not really
desirable. At least, when low-level debug and earlyprint is enabled,
serial console is broken due to it.
Fix the problem by restoring UARTCR2 register at the end of function
lpuart_setup_watermark().
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Ruchika Kharwar [Wed, 17 Jul 2013 13:29:13 +0000 (16:29 +0300)]
serial: omap: Fix IRQ handling return value
Ensure the Interrupt handling routine return IRQ_HANDLED vs
IRQ_NONE.
Signed-off-by: Ruchika Kharwar <ruchika@ti.com>
Signed-off-by: Alexander Savchenko <oleksandr.savchenko@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Vikram Pandita [Mon, 8 Jul 2013 07:25:43 +0000 (10:25 +0300)]
serial: omap: Initialize platform_data
Otherwise serial driver would crash accessing platform_data that was
not initialized in functions like:
serial_omap_pm(...)
...
if (!state && pdata->enable_wakeup)
^^^^^^^
...
Signed-off-by: Vikram Pandita <vikram.pandita@ti.com>
Signed-off-by: Alexander Savchenko <oleksandr.savchenko@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Ruchika Kharwar [Mon, 8 Jul 2013 07:28:57 +0000 (10:28 +0300)]
OMAP: UART: Fix the revision register read.
The revision register is a 32 bit register. The serial_in() function reads
only the lower 16 bits of the register. This leads to an incorrect computation
of the Module revision.
Signed-off-by: Ruchika Kharwar <ruchika@ti.com>
[oleksandr.savchenko@ti.com: add some whitespaces]
Signed-off-by: Alexander Savchenko <oleksandr.savchenko@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Dmitry Fink [Mon, 8 Jul 2013 10:04:44 +0000 (13:04 +0300)]
OMAP: UART: Keep the TX fifo full when possible
Current logic results in interrupt storm since the fifo
is constantly below the threshold level. Change the logic
to fill all the available spaces in the fifo as long as
we have data to minimize the possibilty of underflow and
elimiate excessive interrupts.
Signed-off-by: Dmitry Fink <finik@ti.com>
Signed-off-by: Alexander Savchenko <oleksandr.savchenko@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Govindraj.R [Fri, 5 Jul 2013 15:25:59 +0000 (18:25 +0300)]
OMAP2+: UART: enable tx wakeup bit for wer reg
wer has TX wakeup bit available enable the same
by populating the necessary tx wakeup flag for the
applicable module ip blocks and use the same
while configuaring wer reg.
Also wer is not context restored, restore wer when
context is lost.
Cc: Paul Walmsley <paul@pwsan.com>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Kevin Hilman <kevin.hilman@linaro.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(for drivers/tty changes)
Signed-off-by: Govindraj.R <govindraj.raja@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Stefan Seyfried [Mon, 1 Jul 2013 07:14:21 +0000 (09:14 +0200)]
8250_pci: improve code comments and Kconfig help
The recent regression about NetMos 9835 Multi-I/O boards indicates
that comment pointing to the parport_serial driver could be helpful.
Signed-off-by: Stefan Seyfried <seife+kernel@b1-systems.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Alexander Shiyan [Sat, 29 Jun 2013 06:44:19 +0000 (10:44 +0400)]
serial: max310x: Add MAX14830 support
This patch adds support for MAX14830 (advanced quad universal asynchronous
receiver-transmitter) into max310x driver.
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Alexander Shiyan [Sat, 29 Jun 2013 06:44:18 +0000 (10:44 +0400)]
serial: max310x: Add MAX3109 support
This patch adds support for MAX3109 (advanced dual universal asynchronous
receiver-transmitter) into max310x driver.
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Alexander Shiyan [Sat, 29 Jun 2013 06:44:17 +0000 (10:44 +0400)]
serial: max310x: Driver rework
This patch rework max310x driver.
Major changes have been made:
- Prepare driver to support ICs with more than one UART.
- Prepare driver to support work with I2C-bus.
The patch changes almost every function and can not be divided into parts.
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Huang Shijie [Mon, 8 Jul 2013 09:14:18 +0000 (17:14 +0800)]
serial: imx: add DMA support for imx6q
We only enable the DMA support when the following are meet:
[1] The uart port supports the hardware flow control(CTS/RTS).
(Some uart port does not support the CTS/RTS.)
[2] The application enables the CTS/RTS.
[3] The Soc is imx6q.
For the sdma's firmware limit, we do not support the DMA except
the imx6q platform.
[4] The uart is not used as a console.
Signed-off-by: Huang Shijie <b32955@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Hubert Feurstein [Thu, 18 Jul 2013 16:52:49 +0000 (18:52 +0200)]
serial/imx: fix custom-baudrate handling
It was not possible to set custom-baudrates like 62500.
Signed-off-by: Hubert Feurstein <h.feurstein@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Huang Shijie [Mon, 8 Jul 2013 09:14:17 +0000 (17:14 +0800)]
serial: imx: distinguish the imx6q uart from the others
We will add the DMA support for the imx uart. For the firmware's limit,
only the imx6 serial chips (including the imx6q, imx6dl, imx6sl) can
support the DMA.
This patch adds the necessary macro and helper to distinguish the
imx6q uart from the other imx uart. Other chips can use the "fsl,imx6q-uart"
to enable the DMA support.
This patch also replaces the check "is_imx21_uart()" with "!is_imx1_uart()".
Signed-off-by: Huang Shijie <b32955@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Huang Shijie [Fri, 28 Jun 2013 05:39:42 +0000 (13:39 +0800)]
serial: imx: remove the uart_console() check
The uart_console() check makes the clocks(clk_per and clk_ipg) opened
even when we close the console uart.
This patch enable/disable the clocks in imx_console_write(),
so we can keep the clocks closed when the console uart is closed.
Also remove the clock enable/disable oprations in the probe, we do not
need them any more.
Signed-off-by: Huang Shijie <b32955@freescale.com>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Jingoo Han [Tue, 25 Jun 2013 01:08:49 +0000 (10:08 +0900)]
serial: remove unnecessary platform_set_drvdata()
The driver core clears the driver data to NULL after device_release
or on probe failure, since commit
0998d0631001288a5974afc0b2a5f568bcdecb4d
(device-core: Ensure drvdata = NULL when no driver is bound).
Thus, it is not needed to manually clear the device driver data to NULL.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Acked-by: Barry Song <baohua.song@csr.com>
Acked-by: Tony Prisk <linux@prisktech.co.nz>
Acked-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Hendrik Brueckner [Tue, 2 Jul 2013 15:07:15 +0000 (17:07 +0200)]
tty/hvc_iucv: Disconnect IUCV connection when lowering DTR
Implement the dtr_rts() hvc console callback to improve control when to
disconnect the IUCV connection. Previously, the IUCV connection was
disconnected during the notifier_del() callback, i.e., when the last file
descriptor to the hvc terminal device was closed.
Recent changes in login programs caused undesired disconnects during the
login phase. To prevent these kind of disconnects, implement the dtr_rts
callback to implicitly handle the HUPCL termios control via the hvc_console
driver.
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Hendrik Brueckner [Tue, 2 Jul 2013 15:07:14 +0000 (17:07 +0200)]
tty/hvc_console: Add DTR/RTS callback to handle HUPCL control
Introduce a new callback to explicitly handle the HUPCL termios control flag.
This prepares for a follow-up commit for the hvc_iucv device driver to
improve handling when to drop an established network connection.
The callback naming is based on the recently added tty_port interface to
facilitate a potential refactoring of the hvc_console to use tty_port
functions.
Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Wolfram Sang [Wed, 10 Jul 2013 15:57:46 +0000 (16:57 +0100)]
drivers/tty/serial: don't use devm_pinctrl_get_select_default() in probe
Since commit ab78029 (drivers/pinctrl: grab default handles from device core),
we can rely on device core for setting the default pins. Compile tested only.
Acked-by: Linus Walleij <linus.walleij@linaro.org> (personally at LCE13)
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Aldo Iljazi [Mon, 8 Jul 2013 19:28:00 +0000 (22:28 +0300)]
Drivers: tty: n_gsm.c: fixed 7 errors & 6 warnings that checkpatch complained
Specifically:
n_gsm.c:810: ERROR: space required before the open parenthesis '('
n_gsm.c:830: WARNING: line over 80 characters
n_gsm.c:971: ERROR: trailing whitespace
n_gsm.c:984: ERROR: code indent should use tabs where possible
n_gsm.c:984: WARNING: please, no space before tabs
n_gsm.c:984: WARNING: please, no spaces at the start of a line
n_gsm.c:1141: WARNING: space prohibited before semicolon
n_gsm.c:1743: ERROR: space required before the open brace '{'
n_gsm.c:1744: WARNING: line over 80 characters
n_gsm.c:1745: ERROR: code indent should use tabs where possible
n_gsm.c:1746: ERROR: code indent should use tabs where possible
n_gsm.c:2908: WARNING: line over 80 characters
n_gsm.c:2912: ERROR: trailing whitespace
Signed-off-by: Aldo Iljazi <neonsync1@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Wed, 24 Jul 2013 20:43:51 +0000 (16:43 -0400)]
tty: Fix lock order in tty_do_resize()
Commits
6a1c0680cf3ba94356ecd58833e1540c93472a57 and
9356b535fcb71db494fc434acceb79f56d15bda2, respectively
'tty: Convert termios_mutex to termios_rwsem' and
'n_tty: Access termios values safely'
introduced a circular lock dependency with console_lock and
termios_rwsem.
The lockdep report [1] shows that n_tty_write() will attempt
to claim console_lock while holding the termios_rwsem, whereas
tty_do_resize() may already hold the console_lock while
claiming the termios_rwsem.
Since n_tty_write() and tty_do_resize() do not contend
over the same data -- the tty->winsize structure -- correct
the lock dependency by introducing a new lock which
specifically serializes access to tty->winsize only.
[1] Lockdep report
======================================================
[ INFO: possible circular locking dependency detected ]
3.10.0-0+tip-xeon+lockdep #0+tip Not tainted
-------------------------------------------------------
modprobe/277 is trying to acquire lock:
(&tty->termios_rwsem){++++..}, at: [<
ffffffff81452656>] tty_do_resize+0x36/0xe0
but task is already holding lock:
((fb_notifier_list).rwsem){.+.+.+}, at: [<
ffffffff8107aac6>] __blocking_notifier_call_chain+0x56/0xc0
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 ((fb_notifier_list).rwsem){.+.+.+}:
[<
ffffffff810b6d62>] lock_acquire+0x92/0x1f0
[<
ffffffff8175b797>] down_read+0x47/0x5c
[<
ffffffff8107aac6>] __blocking_notifier_call_chain+0x56/0xc0
[<
ffffffff8107ab46>] blocking_notifier_call_chain+0x16/0x20
[<
ffffffff813d7c0b>] fb_notifier_call_chain+0x1b/0x20
[<
ffffffff813d95b2>] register_framebuffer+0x1e2/0x320
[<
ffffffffa01043e1>] drm_fb_helper_initial_config+0x371/0x540 [drm_kms_helper]
[<
ffffffffa01bcb05>] nouveau_fbcon_init+0x105/0x140 [nouveau]
[<
ffffffffa01ad0af>] nouveau_drm_load+0x43f/0x610 [nouveau]
[<
ffffffffa008a79e>] drm_get_pci_dev+0x17e/0x2a0 [drm]
[<
ffffffffa01ad4da>] nouveau_drm_probe+0x25a/0x2a0 [nouveau]
[<
ffffffff813b13db>] local_pci_probe+0x4b/0x80
[<
ffffffff813b1701>] pci_device_probe+0x111/0x120
[<
ffffffff814977eb>] driver_probe_device+0x8b/0x3a0
[<
ffffffff81497bab>] __driver_attach+0xab/0xb0
[<
ffffffff814956ad>] bus_for_each_dev+0x5d/0xa0
[<
ffffffff814971fe>] driver_attach+0x1e/0x20
[<
ffffffff81496cc1>] bus_add_driver+0x111/0x290
[<
ffffffff814982b7>] driver_register+0x77/0x170
[<
ffffffff813b0454>] __pci_register_driver+0x64/0x70
[<
ffffffffa008a9da>] drm_pci_init+0x11a/0x130 [drm]
[<
ffffffffa022a04d>] nouveau_drm_init+0x4d/0x1000 [nouveau]
[<
ffffffff810002ea>] do_one_initcall+0xea/0x1a0
[<
ffffffff810c54cb>] load_module+0x123b/0x1bf0
[<
ffffffff810c5f57>] SyS_init_module+0xd7/0x120
[<
ffffffff817677c2>] system_call_fastpath+0x16/0x1b
-> #1 (console_lock){+.+.+.}:
[<
ffffffff810b6d62>] lock_acquire+0x92/0x1f0
[<
ffffffff810430a7>] console_lock+0x77/0x80
[<
ffffffff8146b2a1>] con_flush_chars+0x31/0x50
[<
ffffffff8145780c>] n_tty_write+0x1ec/0x4d0
[<
ffffffff814541b9>] tty_write+0x159/0x2e0
[<
ffffffff814543f5>] redirected_tty_write+0xb5/0xc0
[<
ffffffff811ab9d5>] vfs_write+0xc5/0x1f0
[<
ffffffff811abec5>] SyS_write+0x55/0xa0
[<
ffffffff817677c2>] system_call_fastpath+0x16/0x1b
-> #0 (&tty->termios_rwsem){++++..}:
[<
ffffffff810b65c3>] __lock_acquire+0x1c43/0x1d30
[<
ffffffff810b6d62>] lock_acquire+0x92/0x1f0
[<
ffffffff8175b724>] down_write+0x44/0x70
[<
ffffffff81452656>] tty_do_resize+0x36/0xe0
[<
ffffffff8146c841>] vc_do_resize+0x3e1/0x4c0
[<
ffffffff8146c99f>] vc_resize+0x1f/0x30
[<
ffffffff813e4535>] fbcon_init+0x385/0x5a0
[<
ffffffff8146a4bc>] visual_init+0xbc/0x120
[<
ffffffff8146cd13>] do_bind_con_driver+0x163/0x320
[<
ffffffff8146cfa1>] do_take_over_console+0x61/0x70
[<
ffffffff813e2b93>] do_fbcon_takeover+0x63/0xc0
[<
ffffffff813e67a5>] fbcon_event_notify+0x715/0x820
[<
ffffffff81762f9d>] notifier_call_chain+0x5d/0x110
[<
ffffffff8107aadc>] __blocking_notifier_call_chain+0x6c/0xc0
[<
ffffffff8107ab46>] blocking_notifier_call_chain+0x16/0x20
[<
ffffffff813d7c0b>] fb_notifier_call_chain+0x1b/0x20
[<
ffffffff813d95b2>] register_framebuffer+0x1e2/0x320
[<
ffffffffa01043e1>] drm_fb_helper_initial_config+0x371/0x540 [drm_kms_helper]
[<
ffffffffa01bcb05>] nouveau_fbcon_init+0x105/0x140 [nouveau]
[<
ffffffffa01ad0af>] nouveau_drm_load+0x43f/0x610 [nouveau]
[<
ffffffffa008a79e>] drm_get_pci_dev+0x17e/0x2a0 [drm]
[<
ffffffffa01ad4da>] nouveau_drm_probe+0x25a/0x2a0 [nouveau]
[<
ffffffff813b13db>] local_pci_probe+0x4b/0x80
[<
ffffffff813b1701>] pci_device_probe+0x111/0x120
[<
ffffffff814977eb>] driver_probe_device+0x8b/0x3a0
[<
ffffffff81497bab>] __driver_attach+0xab/0xb0
[<
ffffffff814956ad>] bus_for_each_dev+0x5d/0xa0
[<
ffffffff814971fe>] driver_attach+0x1e/0x20
[<
ffffffff81496cc1>] bus_add_driver+0x111/0x290
[<
ffffffff814982b7>] driver_register+0x77/0x170
[<
ffffffff813b0454>] __pci_register_driver+0x64/0x70
[<
ffffffffa008a9da>] drm_pci_init+0x11a/0x130 [drm]
[<
ffffffffa022a04d>] nouveau_drm_init+0x4d/0x1000 [nouveau]
[<
ffffffff810002ea>] do_one_initcall+0xea/0x1a0
[<
ffffffff810c54cb>] load_module+0x123b/0x1bf0
[<
ffffffff810c5f57>] SyS_init_module+0xd7/0x120
[<
ffffffff817677c2>] system_call_fastpath+0x16/0x1b
other info that might help us debug this:
Chain exists of:
&tty->termios_rwsem --> console_lock --> (fb_notifier_list).rwsem
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock((fb_notifier_list).rwsem);
lock(console_lock);
lock((fb_notifier_list).rwsem);
lock(&tty->termios_rwsem);
*** DEADLOCK ***
7 locks held by modprobe/277:
#0: (&__lockdep_no_validate__){......}, at: [<
ffffffff81497b5b>] __driver_attach+0x5b/0xb0
#1: (&__lockdep_no_validate__){......}, at: [<
ffffffff81497b69>] __driver_attach+0x69/0xb0
#2: (drm_global_mutex){+.+.+.}, at: [<
ffffffffa008a6dd>] drm_get_pci_dev+0xbd/0x2a0 [drm]
#3: (registration_lock){+.+.+.}, at: [<
ffffffff813d93f5>] register_framebuffer+0x25/0x320
#4: (&fb_info->lock){+.+.+.}, at: [<
ffffffff813d8116>] lock_fb_info+0x26/0x60
#5: (console_lock){+.+.+.}, at: [<
ffffffff813d95a4>] register_framebuffer+0x1d4/0x320
#6: ((fb_notifier_list).rwsem){.+.+.+}, at: [<
ffffffff8107aac6>] __blocking_notifier_call_chain+0x56/0xc0
stack backtrace:
CPU: 0 PID: 277 Comm: modprobe Not tainted 3.10.0-0+tip-xeon+lockdep #0+tip
Hardware name: Dell Inc. Precision WorkStation T5400 /0RW203, BIOS A11 04/30/2012
ffffffff8213e5e0 ffff8802aa2fb298 ffffffff81755f19 ffff8802aa2fb2e8
ffffffff8174f506 ffff8802aa2fa000 ffff8802aa2fb378 ffff8802aa2ea8e8
ffff8802aa2ea910 ffff8802aa2ea8e8 0000000000000006 0000000000000007
Call Trace:
[<
ffffffff81755f19>] dump_stack+0x19/0x1b
[<
ffffffff8174f506>] print_circular_bug+0x1fb/0x20c
[<
ffffffff810b65c3>] __lock_acquire+0x1c43/0x1d30
[<
ffffffff810b775e>] ? mark_held_locks+0xae/0x120
[<
ffffffff810b78d5>] ? trace_hardirqs_on_caller+0x105/0x1d0
[<
ffffffff810b6d62>] lock_acquire+0x92/0x1f0
[<
ffffffff81452656>] ? tty_do_resize+0x36/0xe0
[<
ffffffff8175b724>] down_write+0x44/0x70
[<
ffffffff81452656>] ? tty_do_resize+0x36/0xe0
[<
ffffffff81452656>] tty_do_resize+0x36/0xe0
[<
ffffffff8146c841>] vc_do_resize+0x3e1/0x4c0
[<
ffffffff8146c99f>] vc_resize+0x1f/0x30
[<
ffffffff813e4535>] fbcon_init+0x385/0x5a0
[<
ffffffff8146a4bc>] visual_init+0xbc/0x120
[<
ffffffff8146cd13>] do_bind_con_driver+0x163/0x320
[<
ffffffff8146cfa1>] do_take_over_console+0x61/0x70
[<
ffffffff813e2b93>] do_fbcon_takeover+0x63/0xc0
[<
ffffffff813e67a5>] fbcon_event_notify+0x715/0x820
[<
ffffffff81762f9d>] notifier_call_chain+0x5d/0x110
[<
ffffffff8107aadc>] __blocking_notifier_call_chain+0x6c/0xc0
[<
ffffffff8107ab46>] blocking_notifier_call_chain+0x16/0x20
[<
ffffffff813d7c0b>] fb_notifier_call_chain+0x1b/0x20
[<
ffffffff813d95b2>] register_framebuffer+0x1e2/0x320
[<
ffffffffa01043e1>] drm_fb_helper_initial_config+0x371/0x540 [drm_kms_helper]
[<
ffffffff8173cbcb>] ? kmemleak_alloc+0x5b/0xc0
[<
ffffffff81198874>] ? kmem_cache_alloc_trace+0x104/0x290
[<
ffffffffa01035e1>] ? drm_fb_helper_single_add_all_connectors+0x81/0xf0 [drm_kms_helper]
[<
ffffffffa01bcb05>] nouveau_fbcon_init+0x105/0x140 [nouveau]
[<
ffffffffa01ad0af>] nouveau_drm_load+0x43f/0x610 [nouveau]
[<
ffffffffa008a79e>] drm_get_pci_dev+0x17e/0x2a0 [drm]
[<
ffffffffa01ad4da>] nouveau_drm_probe+0x25a/0x2a0 [nouveau]
[<
ffffffff8175f162>] ? _raw_spin_unlock_irqrestore+0x42/0x80
[<
ffffffff813b13db>] local_pci_probe+0x4b/0x80
[<
ffffffff813b1701>] pci_device_probe+0x111/0x120
[<
ffffffff814977eb>] driver_probe_device+0x8b/0x3a0
[<
ffffffff81497bab>] __driver_attach+0xab/0xb0
[<
ffffffff81497b00>] ? driver_probe_device+0x3a0/0x3a0
[<
ffffffff814956ad>] bus_for_each_dev+0x5d/0xa0
[<
ffffffff814971fe>] driver_attach+0x1e/0x20
[<
ffffffff81496cc1>] bus_add_driver+0x111/0x290
[<
ffffffffa022a000>] ? 0xffffffffa0229fff
[<
ffffffff814982b7>] driver_register+0x77/0x170
[<
ffffffffa022a000>] ? 0xffffffffa0229fff
[<
ffffffff813b0454>] __pci_register_driver+0x64/0x70
[<
ffffffffa008a9da>] drm_pci_init+0x11a/0x130 [drm]
[<
ffffffffa022a000>] ? 0xffffffffa0229fff
[<
ffffffffa022a000>] ? 0xffffffffa0229fff
[<
ffffffffa022a04d>] nouveau_drm_init+0x4d/0x1000 [nouveau]
[<
ffffffff810002ea>] do_one_initcall+0xea/0x1a0
[<
ffffffff810c54cb>] load_module+0x123b/0x1bf0
[<
ffffffff81399a50>] ? ddebug_proc_open+0xb0/0xb0
[<
ffffffff813855ae>] ? trace_hardirqs_on_thunk+0x3a/0x3f
[<
ffffffff810c5f57>] SyS_init_module+0xd7/0x120
[<
ffffffff817677c2>] system_call_fastpath+0x16/0x1b
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Wed, 24 Jul 2013 12:29:57 +0000 (08:29 -0400)]
tty: Remove extra wakeup from pty write() path
Acquiring the write_wait queue spin lock now accounts for the largest
slice of cpu time on the tty write path. Two factors contribute to
this situation; a overly-pessimistic line discipline write loop which
_always_ sets up a wait loop even if i/o will immediately succeed, and
on ptys, a wakeup storm from reads and writes.
Writer wakeup does not need to be performed by the pty driver.
Firstly, since the actual i/o is performed within the write, the
line discipline write loop will continue while space remains in
the flip buffers. Secondly, when space becomes avail in the
line discipline receive buffer (and thus also in the flip buffers),
the pty unthrottle re-wakes the writer (non-flow-controlled line
disciplines unconditionally unthrottle the driver when data is
received). Thus, existing in-kernel i/o is guaranteed to advance.
Finally, writer wakeup occurs at the conclusion of the line discipline
write (in tty_write_unlock()). This guarantees that any user-space write
waiters are woken to continue additional i/o.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Wed, 24 Jul 2013 12:29:56 +0000 (08:29 -0400)]
n_tty: Factor LNEXT processing from per-char i/o path
LNEXT processing accounts for ~15% of total cpu time in end-to-end
tty i/o; factor the lnext test/clear from the per-char i/o path.
Instead, attempt to immediately handle the literal next char if not
at the end of this received buffer; otherwise, handle the first char
of the next received buffer as the literal next char, then continue
with normal i/o.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Wed, 24 Jul 2013 12:29:55 +0000 (08:29 -0400)]
n_tty: Un-inline single-use functions
gcc will likely inline these single-use functions anyway; remove
inline modifier.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Wed, 24 Jul 2013 12:29:54 +0000 (08:29 -0400)]
n_tty: Remove overflow tests from receive_buf() path
Always pre-figure the space available in the read_buf and limit
the inbound receive request to that amount.
For compatibility reasons with the non-flow-controlled interface,
n_tty_receive_buf() will continue filling read_buf until all data
has been received or receive_room() returns 0.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Wed, 24 Jul 2013 12:29:53 +0000 (08:29 -0400)]
n_tty: Factor PARMRK from normal per-char i/o
Handle PARMRK processing on the slow per-char i/o path.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Wed, 24 Jul 2013 12:29:52 +0000 (08:29 -0400)]
n_tty: Factor ISTRIP and IUCLC receive_buf into separate fn
Convert to modal receive_buf processing; factor char receive
processing for unusual termios settings out of normal per-char
i/o path.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Wed, 24 Jul 2013 12:29:51 +0000 (08:29 -0400)]
n_tty: Split n_tty_receive_char()
Factor 'special' per-char processing into standalone fn,
n_tty_receive_char_special(), which handles processing for chars
marked in the char_map.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Wed, 24 Jul 2013 12:29:50 +0000 (08:29 -0400)]
n_tty: Eliminate char tests from IXANY restart test
Relocate the IXANY restart tty test to code paths where the
the received char is not START_CHAR, STOP_CHAR, INTR_CHAR,
QUIT_CHAR or SUSP_CHAR.
Fixes the condition when ISIG if off and one of INTR_CHAR,
QUIT_CHAR or SUSP_CHAR does not restart i/o.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Wed, 24 Jul 2013 12:29:49 +0000 (08:29 -0400)]
n_tty: Factor standard per-char i/o into separate fn
Simplify __receive_buf() into a dispatch function; perform per-char
processing for all other modes not already handled.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Wed, 24 Jul 2013 13:30:05 +0000 (09:30 -0400)]
n_tty: Fix build breakage on ppc64
Commit
20bafb3d23d108bc0a896eb8b7c1501f4f649b77
'n_tty: Move buffers into n_tty_data'
broke the ppc64 build.
Include vmalloc.h for the required function declarations.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 14:21:27 +0000 (10:21 -0400)]
n_tty: Factor tty->closing receive_buf() into separate fn
Convert to modal receive_buf() processing; factor receive char
processing when tty->closing into n_tty_receive_buf_closing().
Note that EXTPROC when ISTRIP or IUCLC is set continues to be
handled by n_tty_receive_char().
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 14:21:26 +0000 (10:21 -0400)]
n_tty: Special case EXTPROC receive_buf() as raw mode
When EXTPROC is set without ISTRIP or IUCLC, processing is
identical to raw mode; handle this receiving mode as a special-case
of raw mode.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 14:21:25 +0000 (10:21 -0400)]
n_tty: Factor raw mode receive_buf() into separate fn
Convert to modal receive_buf() processing; factor raw mode
per-char i/o into n_tty_receive_buf_raw().
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 14:21:24 +0000 (10:21 -0400)]
n_tty: Factor flagged char handling into separate fn
Prepare for modal receive_buf() handling; factor handling for
TTY_BREAK, TTY_PARITY, TTY_FRAME and TTY_OVERRUN into
n_tty_receive_char_flagged().
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 14:21:23 +0000 (10:21 -0400)]
n_tty: Factor signal char handling into separate fn
Reduce the monolithic n_tty_receive_char() complexity; factor the
handling of INTR_CHAR, QUIT_CHAR and SUSP_CHAR into
n_tty_receive_signal_char().
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 14:21:22 +0000 (10:21 -0400)]
n_tty: Factor 'real raw' receive_buf into standalone fn
Convert to modal receive_buf() processing; factor real_raw
receive_buf() into n_tty_receive_buf_real_raw().
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 14:21:21 +0000 (10:21 -0400)]
n_tty: Simplify __receive_buf loop count
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 14:21:20 +0000 (10:21 -0400)]
n_tty: Rename process_char_map to char_map
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 14:21:19 +0000 (10:21 -0400)]
n_tty: Move buffers into n_tty_data
Reduce pointer reloading and improve locality-of-reference;
allocate read_buf and echo_buf within struct n_tty_data.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 14:21:18 +0000 (10:21 -0400)]
n_tty: Remove alias ptrs in __receive_buf()
The char and flag buffer local alias pointers, p and f, are
unnecessary; remove them.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 14:21:17 +0000 (10:21 -0400)]
n_tty: Fix EOF push handling
In canonical mode, an EOF which is not the first character of the line
causes read() to complete and return the number of characters read so
far (commonly referred to as EOF push). However, if the previous read()
returned because the user buffer was full _and_ the next character
is an EOF not at the beginning of the line, read() must not return 0,
thus mistakenly indicating the end-of-file condition.
The TTY_PUSH flag is used to indicate an EOF was received which is not
at the beginning of the line. Because the EOF push condition is
evaluated by a thread other than the read(), multiple EOF pushes can
cause a premature end-of-file to be indicated.
Instead, discover the 'EOF push as first read character' condition
from the read() thread itself, and restart the i/o loop if detected.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 14:04:29 +0000 (10:04 -0400)]
n_tty: Avoid false-sharing echo buffer indices
Separate the head & commit indices from the tail index to avoid
cache-line contention (so called 'false-sharing') between concurrent
threads.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 14:04:28 +0000 (10:04 -0400)]
n_tty: Eliminate counter in __process_echoes
Since neither echo_commit nor echo_tail can change for the duration
of __process_echoes loop, substitute index comparison for the
snapshot counter.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 14:04:27 +0000 (10:04 -0400)]
n_tty: Only flush echo output if actually output
Don't have the driver flush received echoes if no echoes were
actually output.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 14:04:26 +0000 (10:04 -0400)]
n_tty: Process echoes in blocks
Byte-by-byte echo output is painfully slow, requiring a lock/unlock
cycle for every input byte.
Instead, perform the echo output in blocks of 256 characters, and
at least once per flip buffer receive. Enough space is reserved in
the echo buffer to guarantee a full block can be saved without
overrunning the echo output. Overrun is prevented by discarding
the oldest echoes until enough space exists in the echo buffer
to receive at least a full block of new echoes.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 14:04:25 +0000 (10:04 -0400)]
n_tty: Eliminate echo_commit memory barrier
Use output_lock mutex as a memory barrier when storing echo_commit.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 14:04:24 +0000 (10:04 -0400)]
n_tty: Remove echo_lock
Adding data to echo_buf (via add_echo_byte()) is guaranteed to be
single-threaded, since all callers are from the n_tty_receive_buf()
path. Processing the echo_buf can be called from either the
n_tty_receive_buf() path or the n_tty_write() path; however, these
callers are already serialized by output_lock.
Publish cumulative echo_head changes to echo_commit; process echo_buf
from echo_tail to echo_commit; remove echo_lock.
On echo_buf overrun, claim output_lock to serialize changes to
echo_tail.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 14:04:23 +0000 (10:04 -0400)]
n_tty: Replace echo_cnt with computed value
Prepare for lockless echo_buf handling; compute current byte count
of echo_buf from head and tail indices.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 14:04:22 +0000 (10:04 -0400)]
n_tty: Use separate head and tail indices for echo_buf
Instead of using a single index to track the current echo_buf position,
use a head index when adding to the buffer and a tail index when
consuming from the buffer. Allow these head and tail indices to wrap
at max representable value; perform modulo reduction via helper
functions when accessing the buffer.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 14:04:21 +0000 (10:04 -0400)]
n_tty: Remove unused echo_overrun field
The echo_overrun field is only assigned and never tested; remove it.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:36:16 +0000 (09:36 -0400)]
tty: Remove private constant from global namespace
TTY_BUFFER_PAGE is only used within drivers/tty/tty_buffer.c;
relocate to that file scope.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:36:15 +0000 (09:36 -0400)]
tty: Fix unsafe vt paste_selection()
Convert the tty_buffer_flush() exclusion mechanism to a
public interface - tty_buffer_lock/unlock_exclusive() - and use
the interface to safely write the paste selection to the line
discipline.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:36:14 +0000 (09:36 -0400)]
tty: Merge __tty_flush_buffer() into lone call site
__tty_flush_buffer() is now only called by tty_flush_buffer();
merge functions.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:36:13 +0000 (09:36 -0400)]
tty: Use non-atomic state to signal flip buffer flush pending
Atomic bit ops are no longer required to indicate a flip buffer
flush is pending, as the flush_mutex is sufficient barrier.
Remove the unnecessary port .iflags field and localize flip buffer
state to struct tty_bufhead.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:36:12 +0000 (09:36 -0400)]
tty: Avoid false-sharing flip buffer ptrs
Separate the head and tail ptrs to avoid cache-line contention
(so called 'false-sharing') between concurrent threads.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:36:11 +0000 (09:36 -0400)]
tty: Only perform flip buffer flush from tty_buffer_flush()
Now that dropping the buffer lock is not necessary (as result of
converting the spin lock to a mutex), the flip buffer flush no
longer needs to be handled by the buffer work.
Simply signal a flush is required; the buffer work will exit the
i/o loop, which allows tty_buffer_flush() to proceed.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:36:10 +0000 (09:36 -0400)]
tty: Ensure single-threaded flip buffer consumer with mutex
The buffer work may race with parallel tty_buffer_flush. Use a
mutex to guarantee exclusive modify access to the head flip
buffer.
Remove the unneeded spin lock.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:36:09 +0000 (09:36 -0400)]
tty: Make driver-side flip buffers lockless
Driver-side flip buffer input is already single-threaded; 'publish'
the .next link as the last operation on the tail buffer so the
'consumer' sees the already-completed flip buffer.
The commit buffer index is already 'published' by driver-side functions.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:36:08 +0000 (09:36 -0400)]
tty: Track flip buffer memory limit atomically
Lockless flip buffers require atomically updating the bytes-in-use
watermark.
The pty driver also peeks at the watermark value to limit
memory consumption to a much lower value than the default; query
the watermark with new fn, tty_buffer_space_avail().
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:36:07 +0000 (09:36 -0400)]
tty: Simplify flip buffer list with 0-sized sentinel
Use a 0-sized sentinel to avoid assigning the head ptr from
the driver side thread. This also eliminates testing head/tail
for NULL.
When the sentinel is first 'consumed' by the buffer work
(or by tty_buffer_flush()), it is detached from the list but not
freed nor added to the free list. Both buffer work and
tty_buffer_flush() continue to preserve at least 1 flip buffer
to which head & tail is pointed.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:36:06 +0000 (09:36 -0400)]
tty: Use lockless flip buffer free list
In preparation for lockless flip buffers, make the flip buffer
free list lockless.
NB: using llist is not the optimal solution, as the driver and
buffer work may contend over the llist head unnecessarily. However,
test measurements indicate this contention is low.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:36:05 +0000 (09:36 -0400)]
tty: Use generic names for flip buffer list cursors
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:36:04 +0000 (09:36 -0400)]
tty: Merge tty_buffer_find() into tty_buffer_alloc()
tty_buffer_find() implements a simple free list lookaside cache.
Merge this functionality into tty_buffer_alloc() to reflect the
more traditional alloc/free symmetry.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:36:03 +0000 (09:36 -0400)]
tty: Factor flip buffer initialization into helper function
Factor shared code; prepare for adding 0-sized sentinel flip buffer.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:36:02 +0000 (09:36 -0400)]
tty: Fix flip buffer free list
Since flip buffers are size-aligned to 256 bytes and all flip
buffers 512-bytes or larger are not added to the free list, the
free list only contains 256-byte flip buffers.
Remove the list search when allocating a new flip buffer.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:36:01 +0000 (09:36 -0400)]
tty: Compute flip buffer ptrs
The char_buf_ptr and flag_buf_ptr values are trivially derived from
the .data field offset; compute values as needed.
Fixes a long-standing type-mismatch with the char and flag ptrs.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:14:36 +0000 (09:14 -0400)]
n_tty: Queue buffer work on any available cpu
Scheduling buffer work on the same cpu as the read() thread
limits the parallelism now possible between the receive_buf path
and the n_tty_read() path.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Tue, 23 Jul 2013 12:47:30 +0000 (08:47 -0400)]
n_tty: Special case pty flow control
The pty driver forces ldisc flow control on, regardless of available
receive buffer space, so the writer can be woken whenever unthrottle
is called. However, this 'forced throttle' has performance
consequences, as multiple atomic operations are necessary to
unthrottle and perform the write wakeup for every input line (in
canonical mode).
Instead, short-circuit the unthrottle if the tty is a pty and perform
the write wakeup directly.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:14:34 +0000 (09:14 -0400)]
n_tty: Move n_tty_write_wakeup() to avoid forward declaration
Prepare to special case pty flow control; avoid forward declaration.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:14:33 +0000 (09:14 -0400)]
n_tty: Factor throttle/unthrottle into helper functions
Prepare for special handling of pty throttle/unthrottle; factor
flow control into helper functions.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:14:32 +0000 (09:14 -0400)]
n_tty: Move chars_in_buffer() to factor throttle/unthrottle
Prepare to factor throttle and unthrottle into helper functions;
relocate chars_in_buffer() to avoid forward declaration.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:14:31 +0000 (09:14 -0400)]
tty: Only guarantee termios read safety for throttle/unthrottle
No tty driver modifies termios during throttle() or unthrottle().
Therefore, only read safety is required.
However, tty_throttle_safe and tty_unthrottle_safe must still be
mutually exclusive; introduce throttle_mutex for that purpose.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:14:30 +0000 (09:14 -0400)]
n_tty: Separate buffer indices to prevent cache-line sharing
If the read buffer indices are in the same cache-line, cpus will
contended over the cache-line (so called 'false sharing').
Separate the producer-published fields from the consumer-published
fields; document the locks relevant to each field.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:14:29 +0000 (09:14 -0400)]
n_tty: Don't wait for buffer work in read() loop
User-space read() can run concurrently with receiving from device;
waiting for receive_buf() to complete is not required.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:14:28 +0000 (09:14 -0400)]
n_tty: Fix type mismatches in receive_buf raw copy
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:14:27 +0000 (09:14 -0400)]
n_tty: Reset lnext if canonical mode changes
lnext escapes the next input character as a literal, and must
be reset when canonical mode changes (to avoid misinterpreting
a special character as a literal if canonical mode is changed
back again).
lnext is specifically not reset on a buffer flush so as to avoid
misinterpreting the next input character as a special character.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:14:26 +0000 (09:14 -0400)]
n_tty: Make N_TTY ldisc receive path lockless
n_tty has a single-producer/single-consumer input model;
use lockless publish instead.
Use termios_rwsem to exclude both consumer and producer while
changing or resetting buffer indices, eg., when flushing. Also,
claim exclusive termios_rwsem to safely retrieve the buffer
indices from a thread other than consumer or producer
(eg., TIOCINQ ioctl).
Note the read_tail is published _after_ clearing the newline
indicator in read_flags to avoid racing the producer.
Drop read_lock spinlock.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:14:25 +0000 (09:14 -0400)]
n_tty: Replace canon_data with index comparison
canon_data represented the # of lines which had been copied
to the receive buffer but not yet copied to the user buffer.
The value was tested to determine if input was available in
canonical mode (and also to force input overrun if the
receive buffer was full but a newline had not been received).
However, the actual count was irrelevent; only whether it was
non-zero (meaning 'is there any input to transfer?'). This
shared count is unnecessary and unsafe with a lockless algorithm.
The same check is made by comparing canon_head with read_tail instead.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:14:24 +0000 (09:14 -0400)]
n_tty: Access termios values safely
Use termios_rwsem to guarantee safe access to the termios values.
This is particularly important for N_TTY as changing certain termios
settings alters the mode of operation.
termios_rwsem must be dropped across throttle/unthrottle since
those functions claim the termios_rwsem exclusively (to guarantee
safe access to the termios and for mutual exclusion).
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:14:23 +0000 (09:14 -0400)]
tty: Convert termios_mutex to termios_rwsem
termios is commonly accessed unsafely (especially by N_TTY)
because the existing mutex forces exclusive access.
Convert existing usage.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:14:22 +0000 (09:14 -0400)]
n_tty: Remove read_cnt
Storing the read_cnt creates an unnecessary shared variable
between the single-producer (n_tty_receive_buf()) and the
single-consumer (n_tty_read()).
Compute read_cnt from head & tail instead of storing.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Peter Hurley [Sat, 15 Jun 2013 13:14:21 +0000 (09:14 -0400)]
n_tty: Don't wrap input buffer indices at buffer size
Wrap read_buf indices (read_head, read_tail, canon_head) at
max representable value, instead of at the N_TTY_BUF_SIZE. This step
is necessary to allow lockless reads of these shared variables
(by updating the variables atomically).
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>