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2021-03-13Merge tag 'tty-5.12-rc3' of ↵Linus Torvalds3-40/+9
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty Pull tty/serial fixes from Greg KH: "Here are some small tty and serial driver fixes to resolve some reported problems: - led tty trigger fixes based on review and were acked by the led maintainer - revert a max310x serial driver patch as it was causing problems - revert a pty change as it was also causing problems All of these have been in linux-next for a while with no reported problems" * tag 'tty-5.12-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: Revert "drivers:tty:pty: Fix a race causing data loss on close" Revert "serial: max310x: rework RX interrupt handling" leds: trigger/tty: Use led_set_brightness_sync() from workqueue leds: trigger: Fix error path to not unlock the unlocked mutex
2021-03-10Revert "drivers:tty:pty: Fix a race causing data loss on close"Greg Kroah-Hartman2-16/+4
This reverts commit 33d4ae98859873ddd49e22e4ca724387548b3d89. Pierre-Louis writes: Our SOF/audio CI shows an across-the-board regression when we try v5.12-rc1, specifically on pause/resume tests with an interactive terminal running 'aplay -i' commands managed by expect to simulate the user pressing the space bar to pause/unpause. It turns out the processes are not longer killed and the audio devices remain busy (see publicly available test results listed below). git bisect points to commit 33d4ae9885987 ("drivers:tty:pty: Fix a race causing data loss on close"). Reverting the patch fixes the issue on all test devices. Further analysis with Corey Minyard points to a problem where a slave tty will not get a SIGHUP when the master is closed. So revert this for now: Reported-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com> Link: https://lore.kernel.org/r/00154592-c5ee-aaba-956e-b265473b53bc@linux.intel.com Cc: Corey Minyard <cminyard@mvista.com> Cc: Jiri Slaby <jirislaby@kernel.org> Cc: Mark Brown <broonie@kernel.org>, Fixes: 33d4ae988598 ("drivers:tty:pty: Fix a race causing data loss on close") Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-10Revert "serial: max310x: rework RX interrupt handling"Alexander Shiyan1-24/+5
This reverts commit fce3c5c1a2d9cd888f2987662ce17c0c651916b2. FIFO is triggered 4 intervals after receiving a byte, it's good when we don't care about the time of reception, but are only interested in the presence of any activity on the line. Unfortunately, this method is not suitable for all tasks, for example, the RS-485 protocol will not work properly, since the state machine must track the request-response time and after the timeout expires, a decision is made that the device on the line is not responding. Signed-off-by: Alexander Shiyan <shc_work@mail.ru> Link: https://lore.kernel.org/r/20210217080608.31192-1-shc_work@mail.ru Fixes: fce3c5c1a2d9 ("serial: max310x: rework RX interrupt handling") Cc: Thomas Petazzoni <thomas.petazzoni@bootlin.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-02vio: make remove callback return voidUwe Kleine-König1-3/+1
The driver core ignores the return value of struct bus_type::remove() because there is only little that can be done. To simplify the quest to make this function return void, let struct vio_driver::remove() return void, too. All users already unconditionally return 0, this commit makes it obvious that returning an error code is a bad idea. Note there are two nominally different implementations for a vio bus: one in arch/sparc/kernel/vio.c and the other in arch/powerpc/platforms/pseries/vio.c. This patch only adapts the powerpc one. Before this patch for a device that was bound to a driver without a remove callback vio_cmo_bus_remove(viodev) wasn't called. As the device core still considers the device unbound after vio_bus_remove() returns calling this unconditionally is the consistent behaviour which is implemented here. Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org> Reviewed-by: Tyrel Datwyler <tyreld@linux.ibm.com> Acked-by: Lijun Pan <ljp@linux.ibm.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> [mpe: Drop unneeded hvcs_remove() forward declaration, squash in change from sfr to drop ibmvnic_remove() forward declaration] Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20210225221834.160083-1-uwe@kleine-koenig.org
2021-02-24Merge tag 'char-misc-5.12-rc1' of ↵Linus Torvalds4-493/+0
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc Pull char/misc driver updates from Greg KH: "Here is the large set of char/misc/whatever driver subsystem updates for 5.12-rc1. Over time it seems like this tree is collecting more and more tiny driver subsystems in one place, making it easier for those maintainers, which is why this is getting larger. Included in here are: - coresight driver updates - habannalabs driver updates - virtual acrn driver addition (proper acks from the x86 maintainers) - broadcom misc driver addition - speakup driver updates - soundwire driver updates - fpga driver updates - amba driver updates - mei driver updates - vfio driver updates - greybus driver updates - nvmeem driver updates - phy driver updates - mhi driver updates - interconnect driver udpates - fsl-mc bus driver updates - random driver fix - some small misc driver updates (rtsx, pvpanic, etc.) All of these have been in linux-next for a while, with the only reported issue being a merge conflict due to the dfl_device_id addition from the fpga subsystem in here" * tag 'char-misc-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc: (311 commits) spmi: spmi-pmic-arb: Fix hw_irq overflow Documentation: coresight: Add PID tracing description coresight: etm-perf: Support PID tracing for kernel at EL2 coresight: etm-perf: Clarify comment on perf options ACRN: update MAINTAINERS: mailing list is subscribers-only regmap: sdw-mbq: use MODULE_LICENSE("GPL") regmap: sdw: use no_pm routines for SoundWire 1.2 MBQ regmap: sdw: use _no_pm functions in regmap_read/write soundwire: intel: fix possible crash when no device is detected MAINTAINERS: replace my with email with replacements mhi: Fix double dma free uapi: map_to_7segment: Update example in documentation uio: uio_pci_generic: don't fail probe if pdev->irq equals to IRQ_NOTCONNECTED drivers/misc/vmw_vmci: restrict too big queue size in qp_host_alloc_queue firewire: replace tricky statement by two simple ones vme: make remove callback return void firmware: google: make coreboot driver's remove callback return void firmware: xilinx: Use explicit values for all enum values sample/acrn: Introduce a sample of HSM ioctl interface usage virt: acrn: Introduce an interface for Service VM to control vCPU ...
2021-02-22Merge tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-armLinus Torvalds2-5/+2
Pull ARM updates from Russell King: - Generalise byte swapping assembly - Update debug addresses for STI - Validate start of physical memory with DTB - Do not clear SCTLR.nTLSMD in decompressor - amba/locomo/sa1111 devices remove method return type is void - address markers for KASAN in page table dump * tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm: ARM: 9065/1: OABI compat: fix build when EPOLL is not enabled ARM: 9055/1: mailbox: arm_mhuv2: make remove callback return void amba: Make use of bus_type functions amba: Make the remove callback return void vfio: platform: simplify device removal amba: reorder functions amba: Fix resource leak for drivers without .remove ARM: 9054/1: arch/arm/mm/mmu.c: Remove duplicate header ARM: 9053/1: arm/mm/ptdump:Add address markers for KASAN regions ARM: 9051/1: vdso: remove unneded extra-y addition ARM: 9050/1: Kconfig: Select ARCH_HAVE_NMI_SAFE_CMPXCHG where possible ARM: 9049/1: locomo: make locomo bus's remove callback return void ARM: 9048/1: sa1111: make sa1111 bus's remove callback return void ARM: 9047/1: smp: remove unused variable ARM: 9046/1: decompressor: Do not clear SCTLR.nTLSMD for ARMv7+ cores ARM: 9045/1: uncompress: Validate start of physical memory against passed DTB ARM: 9042/1: debug: no uncompress debugging while semihosting ARM: 9041/1: sti LL_UART: add STiH418 SBC UART0 support ARM: 9040/1: use DEBUG_UART_PHYS and DEBUG_UART_VIRT for sti LL_UART ARM: 9039/1: assembler: generalize byte swapping macro into rev_l
2021-02-22Merge tag 'devicetree-for-5.12' of ↵Linus Torvalds2-38/+35
git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux Pull devicetree updates from Rob Herring: - Sync dtc to upstream version v1.6.0-51-g183df9e9c2b9 and build host fdtoverlay - Add kbuild support to build DT overlays (%.dtbo) - Drop NULLifying match table in of_match_device(). In preparation for this, there are several driver cleanups to use (of_)?device_get_match_data(). - Drop pointless wrappers from DT struct device API - Convert USB binding schemas to use graph schema and remove old plain text graph binding doc - Convert spi-nor and v3d GPU bindings to DT schema - Tree wide schema fixes for if/then schemas, array size constraints, and undocumented compatible strings in examples - Handle 'no-map' correctly for already reserved memblock regions * tag 'devicetree-for-5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: (35 commits) driver core: platform: Drop of_device_node_put() wrapper of: Remove of_dev_{get,put}() dt-bindings: usb: Change descibe to describe in usbmisc-imx.txt dt-bindings: can: rcar_canfd: Group tuples in pin control properties dt-bindings: power: renesas,apmu: Group tuples in cpus properties dt-bindings: mtd: spi-nor: Convert to DT schema format dt-bindings: Use portable sort for version cmp dt-bindings: ethernet-controller: fix fixed-link specification dt-bindings: irqchip: Add node name to PRUSS INTC dt-bindings: interconnect: Fix the expected number of cells dt-bindings: Fix errors in 'if' schemas dt-bindings: iommu: renesas,ipmmu-vmsa: Make 'power-domains' conditionally required dt-bindings: Fix undocumented compatible strings in examples kbuild: Add support to build overlays (%.dtbo) scripts: dtc: Remove the unused fdtdump.c file scripts: dtc: Build fdtoverlay tool scripts/dtc: Update to upstream version v1.6.0-51-g183df9e9c2b9 scripts: dtc: Fetch fdtoverlay.c from external DTC project dt-bindings: thermal: sun8i: Fix misplaced schema keyword in compatible strings dt-bindings: iio: dac: Fix AD5686 references ...
2021-02-20Merge tag 'tty-5.12-rc1' of ↵Linus Torvalds38-5009/+710
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty Pull tty/serial driver updates from Greg KH: "Here is the big set of tty/serial driver changes for 5.12-rc1. Nothing huge, just lots of good cleanups and additions: - n_tty line discipline cleanups - vt core cleanups and reworks to make the code more "modern" - stm32 driver additions - tty led support added to the tty core and led layer - minor serial driver fixups and additions All of these have been in linux-next for a while with no reported issues" * tag 'tty-5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (54 commits) serial: core: Remove BUG_ON(in_interrupt()) check vt_ioctl: Remove in_interrupt() check dt-bindings: serial: imx: Switch to my personal address vt: keyboard, use new API for keyboard_tasklet serial: stm32: improve platform_get_irq condition handling in init_port serial: ifx6x60: Remove driver for deprecated platform tty: fix up iterate_tty_read() EOVERFLOW handling tty: fix up hung_up_tty_read() conversion tty: fix up hung_up_tty_write() conversion tty: teach the n_tty ICANON case about the new "cookie continuations" too tty: teach n_tty line discipline about the new "cookie continuations" tty: clean up legacy leftovers from n_tty line discipline tty: implement read_iter tty: convert tty_ldisc_ops 'read()' function to take a kernel pointer serial: remove sirf prima/atlas driver serial: mxs-auart: Remove <asm/cacheflush.h> serial: mxs-auart: Remove serial_mxs_probe_dt() serial: fsl_lpuart: Use of_device_get_match_data() dt-bindings: serial: renesas,hscif: Add r8a779a0 support tty: serial: Drop unused efm32 serial driver ...
2021-02-20tty: protect tty_write from odd low-level tty disciplinesLinus Torvalds1-1/+4
Al root-caused a new warning from syzbot to the ttyprintk tty driver returning a write count larger than the data the tty layer actually gave it. Which confused the tty write code mightily, and with the new iov_iter based code, caused a WARNING in iov_iter_revert(). syzbot correctly bisected the source of the new warning to commit 9bb48c82aced ("tty: implement write_iter"), but the oddity goes back much further, it just didn't get caught by anything before. Reported-by: syzbot+3d2c27c2b7dc2a94814d@syzkaller.appspotmail.com Fixes: 9bb48c82aced ("tty: implement write_iter") Debugged-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-02-09serial: core: Remove BUG_ON(in_interrupt()) checkAhmed S. Darwish1-4/+4
The usage of in_interrupt() in drivers is phased out for various reasons. In both exported functions where BUG_ON(in_interrupt()) is invoked, there is a mutex_lock() afterwards. mutex_lock() contains a might_sleep() which will already trigger a stack trace if the target functions is called from atomic context. Remove the BUG_ON() and add a "Context: " in the kernel-doc instead. Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Link: https://lore.kernel.org/r/20210208181615.381861-3-bigeasy@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-02-09vt_ioctl: Remove in_interrupt() checkAhmed S. Darwish1-2/+1
reset_vc() uses a "!in_interrupt()" conditional before resetting the palettes, which is a blocking operation. Since commit 8b6312f4dcc1e ("[PATCH] vt: refactor console SAK processing") all calls are invoked from a workqueue process context, with the blocking console lock always acquired. Remove the "!in_interrupt()" check. Signed-off-by: Ahmed S. Darwish <a.darwish@linutronix.de> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Link: https://lore.kernel.org/r/20210208181615.381861-2-bigeasy@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-02-05Merge branch 'devel-stable' of git://git.armlinux.org.uk/~rmk/linux-arm into ↵Greg Kroah-Hartman2-5/+2
char-misc-next This merges from linux-arm at 860660fd829e ("ARM: 9055/1: mailbox: arm_mhuv2: make remove callback return void") into char-misc-next to get the amba fixes from Uwe. Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Cc: Russell King <linux@armlinux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-02-02amba: Make the remove callback return voidUwe Kleine-König2-5/+2
All amba drivers return 0 in their remove callback. Together with the driver core ignoring the return value anyhow, it doesn't make sense to return a value here. Change the remove prototype to return void, which makes it explicit that returning an error value doesn't work as expected. This simplifies changing the core remove callback to return void, too. Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org> Reviewed-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Acked-by: Krzysztof Kozlowski <krzk@kernel.org> # for drivers/memory Acked-by: Mark Brown <broonie@kernel.org> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Suzuki K Poulose <suzuki.poulose@arm.com> # for hwtracing/coresight Acked-By: Vinod Koul <vkoul@kernel.org> # for dmaengine Acked-by: Guenter Roeck <linux@roeck-us.net> # for watchdog Acked-by: Wolfram Sang <wsa@kernel.org> # for I2C Acked-by: Takashi Iwai <tiwai@suse.de> # for sound Acked-by: Vladimir Zapolskiy <vz@mleia.com> # for memory/pl172 Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Link: https://lore.kernel.org/r/20210126165835.687514-5-u.kleine-koenig@pengutronix.de Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
2021-01-29tty: avoid using vfs_iocb_iter_write() for redirected console writesLinus Torvalds1-3/+17
It turns out that the vfs_iocb_iter_{read,write}() functions are entirely broken, and don't actually use the passed-in file pointer for IO - only for the preparatory work (permission checking and for the write_iter function lookup). That worked fine for overlayfs, which always builds the new iocb with the same file pointer that it passes in, but in the general case it ends up doing nonsensical things (and could cause an iterator call that doesn't even match the passed-in file pointer). This subtly broke the tty conversion to write_iter in commit 9bb48c82aced ("tty: implement write_iter"), because the console redirection didn't actually end up redirecting anything, since the passed-in file pointer was basically ignored, and the actual write was done with the original non-redirected console tty after all. The main visible effect of this is that the console messages were no longer logged to /var/log/boot.log during graphical boot. Fix the issue by simply not using the vfs write "helper" function at all, and just redirecting the write entirely internally to the tty layer. Do the target writability permission checks when actually registering the target tty with TIOCCONS instead of at write time. Fixes: 9bb48c82aced ("tty: implement write_iter") Reported-and-tested-by: Hans de Goede <hdegoede@redhat.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: stable@kernel.org Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-01-27vt: keyboard, use new API for keyboard_taskletEmil Renner Berthing1-3/+3
This converts the keyboard_tasklet to use the new API in commit 12cc923f1ccc ("tasklet: Introduce new initialization API") The new API changes the argument passed to the callback function, but fortunately the argument isn't used so it is straight forward to use DECLARE_TASKLET_DISABLED() rather than DECLARE_TASKLET_DISABLED_OLD(). Signed-off-by: Emil Renner Berthing <kernel@esmil.dk> Link: https://lore.kernel.org/r/20210127164222.13220-1-kernel@esmil.dk Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-27misc: pti: Remove driver for deprecated platformAndy Shevchenko4-489/+0
Intel Moorestown and Medfield are quite old Intel Atom based 32-bit platforms, which were in limited use in some Android phones, tablets and consumer electronics more than eight years ago. There are no bugs or problems ever reported outside from Intel for breaking any of that platforms for years. It seems no real users exists who run more or less fresh kernel on it. The commit 05f4434bc130 ("ASoC: Intel: remove mfld_machine") also in align with this theory. Due to above and to reduce a burden of supporting outdated drivers we remove the support of outdated platforms completely. Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Alexander Shishkin <alexander.shishkin@linux.intel.com> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Link: https://lore.kernel.org/r/20210122114358.39299-1-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-26serial: stm32: improve platform_get_irq condition handling in init_portErwan Le Ray1-5/+5
Replace "ret" variable by "irq" variable from platform_get_irq condition handling in stm32_init_port as suggested by Jiri in "STM32 uart cleanup and improvement" series review. This change will prevent port->irq to be unexpectly modified by a potential change of "ret" value introduced by a new patch. Suggested-by: Jiri Slaby <jirislaby@kernel.org> Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com> Link: https://lore.kernel.org/r/20210121142309.6327-1-erwan.leray@foss.st.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-26serial: ifx6x60: Remove driver for deprecated platformAndy Shevchenko4-1513/+0
Intel Moorestown and Medfield are quite old Intel Atom based 32-bit platforms, which were in limited use in some Android phones, tablets and consumer electronics more than eight years ago. There are no bugs or problems ever reported outside from Intel for breaking any of that platforms for years. It seems no real users exists who run more or less fresh kernel on it. The commit 05f4434bc130 ("ASoC: Intel: remove mfld_machine") also in align with this theory. Due to above and to reduce a burden of supporting outdated drivers we remove the support of outdated platforms completely. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Link: https://lore.kernel.org/r/20210125150238.16980-1-andriy.shevchenko@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-26serial: stm32: Use of_device_get_match_data()Stephen Boyd2-38/+35
This driver casts away the constness of struct stm32_usart_info that is pointed to by the of match table. Use of_device_get_match_data() instead of of_match_device() here and push the const throughout the code so that we don't cast away const. This nicely avoids referencing the match table when it is undefined with configurations where CONFIG_OF=n and fixes the const issues. Signed-off-by: Stephen Boyd <swboyd@chromium.org> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jslaby@suse.com> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com> Cc: Alexandre Torgue <alexandre.torgue@st.com> Cc: Rob Herring <robh+dt@kernel.org> Cc: Frank Rowand <frowand.list@gmail.com> Cc: <linux-serial@vger.kernel.org> Signed-off-by: Rob Herring <robh@kernel.org> Link: https://lore.kernel.org/r/20210123034428.2841052-4-swboyd@chromium.org
2021-01-25Commit 9bb48c82aced ("tty: implement write_iter") converted the ttySami Tolvanen2-7/+2
layer to use write_iter. Fix the redirected_tty_write declaration also in n_tty and change the comparisons to use write_iter instead of write. [ Also moved the declaration of redirected_tty_write() to the proper location in a header file. The reason for the bug was the bogus extern declaration in n_tty.c silently not matching the changed definition in tty_io.c, and because it wasn't in a shared header file, there was no cross-checking of the declaration. Sami noticed because Clang's Control Flow Integrity checking ended up incidentally noticing the inconsistent declaration. - Linus ] Fixes: 9bb48c82aced ("tty: implement write_iter") Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-01-25Merge 5.11-rc5 into tty-nextGreg Kroah-Hartman5-20/+26
We need the fixes in here and this resolves a merge issue in drivers/tty/tty_io.c Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-24Merge tag 'tty-5.11-rc5' of ↵Linus Torvalds2-24/+37
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty Pull tty/serial fixes from Greg KH: "Here are three small tty/serial fixes for 5.11-rc5 to resolve reported problems: - two patches to fix up writing to ttys with splice - mvebu-uart driver fix for reported problem All of these have been in linux-next with no reported problems" * tag 'tty-5.11-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: tty: fix up hung_up_tty_write() conversion tty: implement write_iter serial: mvebu-uart: fix tx lost characters at power off
2021-01-22tty: fix up hung_up_tty_write() conversionLinus Torvalds1-4/+5
In commit "tty: implement write_iter", I left the write_iter conversion of the hung up tty case alone, because I incorrectly thought it didn't matter. Jiri showed me the errors of my ways, and pointed out the problems with that incomplete conversion. Fix it all up. Reported-by: Jiri Slaby <jirislaby@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Jiri Slaby <jirislaby@kernel.org> Link: https://lore.kernel.org/r/CAHk-=wh+-rGsa=xruEWdg_fJViFG8rN9bpLrfLz=_yBYh2tBhA@mail.gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-22tty: fix up iterate_tty_read() EOVERFLOW handlingLinus Torvalds1-6/+13
When I converted the tty_ldisc_ops 'read()' function to take a kernel pointer, I was a bit too aggressive about the ldisc returning EOVERFLOW. Yes, we want to have EOVERFLOW override any partially read data (because the whole point is that the buffer was too small for the whole packet, and we don't want to see partial packets), but it shouldn't override a previous EFAULT. And in fact, it really is just EOVERFLOW that is special and should throw away any partially read data, not "any error". Admittedly EOVERFLOW is currently the only one that can happen for a continuation read - and if the first read iteration returns an error we won't have this issue. So this is more of a technicality, but let's just make the intent very explicit, and re-organize the error handling a bit so that this is all clearer. Reported-by: Jiri Slaby <jirislaby@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Jiri Slaby <jirislaby@kernel.org> Link: https://lore.kernel.org/r/CAHk-=wh+-rGsa=xruEWdg_fJViFG8rN9bpLrfLz=_yBYh2tBhA@mail.gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-22tty: fix up hung_up_tty_read() conversionLinus Torvalds1-4/+5
In commit "tty: implement read_iter", I left the read_iter conversion of the hung up tty case alone, because I incorrectly thought it didn't matter. Jiri showed me the errors of my ways, and pointed out the problems with that incomplete conversion. Fix it all up. Reported-by: Jiri Slaby <jirislaby@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Jiri Slaby <jirislaby@kernel.org> Link: https://lore.kernel.org/r/CAHk-=wh+-rGsa=xruEWdg_fJViFG8rN9bpLrfLz=_yBYh2tBhA@mail.gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-22tty: fix up hung_up_tty_write() conversionLinus Torvalds1-4/+5
In commit "tty: implement write_iter", I left the write_iter conversion of the hung up tty case alone, because I incorrectly thought it didn't matter. Jiri showed me the errors of my ways, and pointed out the problems with that incomplete conversion. Fix it all up. Reported-by: Jiri Slaby <jirislaby@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Reviewed-by: Jiri Slaby <jirislaby@kernel.org> Link: https://lore.kernel.org/r/CAHk-=wh+-rGsa=xruEWdg_fJViFG8rN9bpLrfLz=_yBYh2tBhA@mail.gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-21Merge branch 'tty-splice' of ↵Greg Kroah-Hartman8-129/+236
git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux into tty-next Fixes both the "splice/sendfile to a tty" and "splice/sendfile from a tty" regression from 5.10. * 'tty-splice' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux: tty: teach the n_tty ICANON case about the new "cookie continuations" too tty: teach n_tty line discipline about the new "cookie continuations" tty: clean up legacy leftovers from n_tty line discipline tty: implement read_iter tty: convert tty_ldisc_ops 'read()' function to take a kernel pointer tty: implement write_iter
2021-01-21Merge 9bb48c82aced ("tty: implement write_iter") into tty-linusGreg Kroah-Hartman1-22/+26
We want the single "splice/sendfile to a tty" regression fix into tty-linus so it can get into 5.11-final, while the larger patch series fixing "splice/sendfile from a tty" should wait for 5.12-rc1 so that we get more testing. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-20tty: teach the n_tty ICANON case about the new "cookie continuations" tooLinus Torvalds1-7/+19
The ICANON case is a bit messy, since it has to look for the line ending, and has special code to then suppress line ending characters if they match the __DISABLED_CHAR. So it actually looks up the line ending even past the point where it knows it won't copy it to the result buffer. That said, apart from all those odd legacy N_TTY ICANON cases, the actual "should we continue copying" logic isn't really all that complicated or different from the non-canon case. In fact, the lack of "wait for at least N characters" arguably makes the repeat case slightly simpler. It really just boils down to "there's more of the line to be copied". So add the necessarily trivial logic, and now the N_TTY case will give long result lines even when in canon mode. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-01-20tty: teach n_tty line discipline about the new "cookie continuations"Linus Torvalds1-10/+42
With the conversion to do the tty ldisc read operations in small chunks, the n_tty line discipline became noticeably slower for throughput oriented loads, because rather than read things in up to 2kB chunks, it would return at most 64 bytes per read() system call. The cost is mainly all in the "do system calls over and over", not really in the new "copy to an extra kernel buffer". This can be fixed by teaching the n_tty line discipline about the "cookie continuation" model, which the chunking code supports because things like hdlc need to be able to handle packets up to 64kB in size. Doing that doesn't just get us back to the old performace, but to much better performance: my stupid "copy 10MB of data over a pty" test program is now almost twice as fast as it used to be (going down from 0.1s to 0.054s). This is entirely because it now creates maximal chunks (which happens to be "one byte less than one page" due to how we do the circular tty buffers). NOTE! This case only handles the simpler non-icanon case, which is the one where people may care about throughput. I'm going to do the icanon case later too, because while performance isn't a major issue for that, there may be programs that think they'll always get a full line and don't like the 64-byte chunking for that reason. Such programs are arguably buggy (signals etc can cause random partial results from tty reads anyway), and good programs will handle such partial reads, but expecting everybody to write "good programs" has never been a winning policy for the kernel.. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-01-20tty: clean up legacy leftovers from n_tty line disciplineLinus Torvalds1-20/+9
Back when the line disciplines did their own direct user accesses, they had to deal with the data copy possibly failing in the middle. Now that the user copy is done by the tty_io.c code, that failure case no longer exists. Remove the left-over error handling code that cannot trigger. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-01-20tty: implement write_iterLinus Torvalds1-22/+26
This makes the tty layer use the .write_iter() function instead of the traditional .write() functionality. That allows writev(), but more importantly also makes it possible to enable .splice_write() for ttys, reinstating the "splice to tty" functionality that was lost in commit 36e2c7421f02 ("fs: don't allow splice read/write without explicit ops"). Fixes: 36e2c7421f02 ("fs: don't allow splice read/write without explicit ops") Reported-by: Oliver Giles <ohw.giles@gmail.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-01-20tty: implement read_iterLinus Torvalds1-18/+18
Now that the ldisc read() function takes kernel pointers, it's fairly straightforward to make the tty file operations use .read_iter() instead of .read(). That automatically gives us vread() and friends, and also makes it possible to do .splice_read() on ttys again. Fixes: 36e2c7421f02 ("fs: don't allow splice read/write without explicit ops") Reported-by: Oliver Giles <ohw.giles@gmail.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-01-20tty: convert tty_ldisc_ops 'read()' function to take a kernel pointerLinus Torvalds8-80/+150
The tty line discipline .read() function was passed the final user pointer destination as an argument, which doesn't match the 'write()' function, and makes it very inconvenient to do a splice method for ttys. This is a conversion to use a kernel buffer instead. NOTE! It does this by passing the tty line discipline ->read() function an additional "cookie" to fill in, and an offset into the cookie data. The line discipline can fill in the cookie data with its own private information, and then the reader will repeat the read until either the cookie is cleared or it runs out of data. The only real user of this is N_HDLC, which can use this to handle big packets, even if the kernel buffer is smaller than the whole packet. Cc: Christoph Hellwig <hch@lst.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-01-20serial: remove sirf prima/atlas driverArnd Bergmann4-1973/+0
The CSR SiRF prima2/atlas platforms are getting removed, so this driver is no longer needed. Cc: Barry Song <baohua@kernel.org> Signed-off-by: Arnd Bergmann <arnd@arndb.de> Link: https://lore.kernel.org/r/20210120161324.3728294-1-arnd@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-20serial: mxs-auart: Remove <asm/cacheflush.h>Fabio Estevam1-2/+0
There is nothing in the driver that uses the definitions from <asm/cacheflush.h>. Remove the unused header file inclusion. Signed-off-by: Fabio Estevam <festevam@gmail.com> Link: https://lore.kernel.org/r/20210118152154.1644569-2-festevam@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-20serial: mxs-auart: Remove serial_mxs_probe_dt()Fabio Estevam1-32/+11
The mxs platform is devicetree-only, so there is no need to check whether it was instantiated via devicetree. Simplify the code my removing serial_mxs_probe_dt() and add its content into the main probe function. Signed-off-by: Fabio Estevam <festevam@gmail.com> Link: https://lore.kernel.org/r/20210118152154.1644569-1-festevam@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-20serial: fsl_lpuart: Use of_device_get_match_data()Fabio Estevam1-3/+1
The retrieval of driver data via of_device_get_match_data() can make the code simpler. Use of_device_get_match_data() to simplify the code. Signed-off-by: Fabio Estevam <festevam@gmail.com> Link: https://lore.kernel.org/r/20210118124447.1632092-1-festevam@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-16Merge tag 'riscv-for-linus-5.11-rc4' of ↵Linus Torvalds1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux Pull RISC-V fixes from Palmer Dabbelt: "There are a few more fixes than a normal rc4, largely due to the bubble introduced by the holiday break: - return -ENOSYS for syscall number -1, which previously returned an uninitialized value. - ensure of_clk_init() has been called in time_init(), without which clock drivers may not be initialized. - fix sifive,uart0 driver to properly display the baud rate. A fix to initialize MPIE that allows interrupts to be processed during system calls. - avoid erronously begin tracing IRQs when interrupts are disabled, which at least triggers suprious lockdep failures. - workaround for a warning related to calling smp_processor_id() while preemptible. The warning itself is suprious on currently availiable systems. - properly include the generic time VDSO calls. A fix to our kasan address mapping. A fix to the HiFive Unleashed device tree, which allows the Ethernet PHY to be properly initialized by Linux (as opposed to relying on the bootloader). - defconfig update to include SiFive's GPIO driver, which is present on the HiFive Unleashed and necessary to initialize the PHY. - avoid allocating memory while initializing reserved memory. - avoid allocating the last 4K of memory, as pointers there alias with syscall errors. There are also two cleanups that should have no functional effect but do fix build warnings: - drop a duplicated definition of PAGE_KERNEL_EXEC. - properly declare the asm register SP shim. - cleanup the rv32 memory size Kconfig entry, to reflect the actual size of memory availiable" * tag 'riscv-for-linus-5.11-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: RISC-V: Fix maximum allowed phsyical memory for RV32 RISC-V: Set current memblock limit RISC-V: Do not allocate memblock while iterating reserved memblocks riscv: stacktrace: Move register keyword to beginning of declaration riscv: defconfig: enable gpio support for HiFive Unleashed dts: phy: add GPIO number and active state used for phy reset dts: phy: fix missing mdio device and probe failure of vsc8541-01 device riscv: Fix KASAN memory mapping. riscv: Fixup CONFIG_GENERIC_TIME_VSYSCALL riscv: cacheinfo: Fix using smp_processor_id() in preemptible riscv: Trace irq on only interrupt is enabled riscv: Drop a duplicated PAGE_KERNEL_EXEC riscv: Enable interrupts during syscalls with M-Mode riscv: Fix sifive serial driver riscv: Fix kernel time_init() riscv: return -ENOSYS for syscall -1
2021-01-15tty: serial: Drop unused efm32 serial driverUwe Kleine-König3-866/+0
Support for this machine was just removed, so drop the now unused UART driver, too. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Link: https://lore.kernel.org/r/20210115155130.185010-7-u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-15tty: vcc: Drop impossible to hit WARN_ONUwe Kleine-König1-5/+2
vcc_get() returns the port that has provided port->index. As the port that is about to be removed isn't removed yet this trivially will find this port. So simplify the call to not assign an identical value to the port pointer and drop the warning that is never hit. Reviewed-by: Jiri Slaby <jirislaby@kernel.org> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Link: https://lore.kernel.org/r/20210114175718.137483-4-u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-15tty: vcc: Drop unnecessary if blockUwe Kleine-König1-3/+0
If vcc_probe() succeeded dev_set_drvdata() is called with a non-NULL value, and if vcc_probe() failed vcc_remove() isn't called. So there is no way dev_get_drvdata() can return NULL in vcc_remove() and the check can just go away. Reviewed-by: Jiri Slaby <jirislaby@kernel.org> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Link: https://lore.kernel.org/r/20210114175718.137483-3-u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-15tty: hvcs: Drop unnecessary if blockUwe Kleine-König1-3/+0
If hvcs_probe() succeeded dev_set_drvdata() is called with a non-NULL value, and if hvcs_probe() failed hvcs_remove() isn't called. So there is no way dev_get_drvdata() can return NULL in hvcs_remove() and the check can just go away. Reviewed-by: Jiri Slaby <jirislaby@kernel.org> Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Link: https://lore.kernel.org/r/20210114175718.137483-2-u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-13tty: serial: owl: Add support for kernel debuggerCristian Ciocaltea1-0/+38
Implement 'poll_put_char' and 'poll_get_char' callbacks in struct 'owl_uart_ops' that enables OWL UART to be used for kernel debugging over serial line. Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@gmail.com> Link: https://lore.kernel.org/r/026543195b9aeefb339d90abc5660a6ac7463c63.1610484108.git.cristian.ciocaltea@gmail.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-08Revert "init/console: Use ttynull as a fallback when there is no console"Petr Mladek3-19/+16
This reverts commit 757055ae8dedf5333af17b3b5b4b70ba9bc9da4e. The commit caused that ttynull was used as the default console on several systems[1][2][3]. As a result, the console was blank even when a better alternative existed. It happened when there was no console configured on the command line and ttynull_init() was the first initcall calling register_console(). Or it happened when /dev/ did not exist when console_on_rootfs() was called. It was not able to open /dev/console even though a console driver was registered. It tried to add ttynull console but it obviously did not help. But ttynull became the preferred console and was used by /dev/console when it was available later. The commit tried to fix a historical problem that have been there for ages. The primary motivation was the commit 3cffa06aeef7ece30f6 ("printk/console: Allow to disable console output by using console="" or console=null"). It provided a clean solution for a workaround that was widely used and worked only by chance. This revert causes that the console="" or console=null command line options will again work only by chance. These options will cause that a particular console will be preferred and the default (tty) ones will not get enabled. There will be no console registered at all. As a result there won't be stdin, stdout, and stderr for the init process. But it worked exactly this way even before. The proper solution has to fulfill many conditions: + Register ttynull only when explicitly required or as the ultimate fallback. + ttynull should get associated with /dev/console but it must not become preferred console when used as a fallback. Especially, it must still be possible to replace it by a better console later. Such a change requires clean up of the register_console() code. Otherwise, it would be even harder to follow. Especially, the use of has_preferred_console and CON_CONSDEV flag is tricky. The clean up is risky. The ordering of consoles is not well defined. And any changes tend to break existing user settings. Do the revert at the least risky solution for now. [1] https://lore.kernel.org/linux-kselftest/20201221144302.GR4077@smile.fi.intel.com/ [2] https://lore.kernel.org/lkml/d2a3b3c0-e548-7dd1-730f-59bc5c04e191@synopsys.com/ [3] https://patchwork.ozlabs.org/project/linux-um/patch/20210105120128.10854-1-thomas@m3y3r.de/ Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reported-by: Vineet Gupta <vgupta@synopsys.com> Reported-by: Thomas Meyer <thomas@m3y3r.de> Signed-off-by: Petr Mladek <pmladek@suse.com> Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Acked-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-01-07riscv: Fix sifive serial driverDamien Le Moal1-0/+1
Setup the port uartclk in sifive_serial_probe() so that the base baud rate is correctly printed during device probe instead of always showing "0". I.e. the probe message is changed from 38000000.serial: ttySIF0 at MMIO 0x38000000 (irq = 1, base_baud = 0) is a SiFive UART v0 to the correct: 38000000.serial: ttySIF0 at MMIO 0x38000000 (irq = 1, base_baud = 115200) is a SiFive UART v0 Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com> Acked-by: Palmer Dabbelt <palmerdabbelt@google.com> Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-01-07tty: Protect disc_data in n_tty_close and n_tty_flush_bufferYan.Gao1-0/+2
n_tty_flush_buffer can happen in parallel with n_tty_close that the tty->disc_data will be set to NULL. n_tty_flush_buffer accesses tty->disc_data, so we must prevent n_tty_close clear tty->disc_data while n_tty_flush_buffer has a non-NULL view of tty->disc_data. So we need to make sure that accesses to disc_data are atomic using tty->termios_rwsem. There is an example I meet: When n_tty_flush_buffer accesses tty struct, the disc_data is right. However, then reset_buffer_flags accesses tty->disc_data, disc_data become NULL, So kernel crash when accesses tty->disc_data->real_tail. I guess there could be another thread change tty->disc_data to NULL, and during N_TTY line discipline, n_tty_close will set tty->disc_data to be NULL. So use tty->termios_rwsem to protect disc_data between close and flush_buffer. IP: reset_buffer_flags+0x9/0xf0 PGD 0 P4D 0 Oops: 0002 [#1] SMP CPU: 23 PID: 2087626 Comm: (agetty) Kdump: loaded Tainted: G Hardware name: UNISINSIGHT X3036P-G3/ST01M2C7S, BIOS 2.00.13 01/11/2019 task: ffff9c4e9da71e80 task.stack: ffffb30cfe898000 RIP: 0010:reset_buffer_flags+0x9/0xf0 RSP: 0018:ffffb30cfe89bca8 EFLAGS: 00010246 RAX: ffff9c4e9da71e80 RBX: ffff9c368d1bac00 RCX: 0000000000000000 RDX: 0000000000000000 RSI: ffff9c4ea17b50f0 RDI: 0000000000000000 RBP: ffffb30cfe89bcc8 R08: 0000000000000100 R09: 0000000000000001 R10: 0000000000000001 R11: 0000000000000000 R12: ffff9c368d1bacc0 R13: ffff9c20cfd18428 R14: ffff9c4ea17b50f0 R15: ffff9c368d1bac00 FS: 00007f9fbbe97940(0000) GS:ffff9c375c740000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000002260 CR3: 0000002f72233003 CR4: 00000000007606e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: ? n_tty_flush_buffer+0x2a/0x60 tty_buffer_flush+0x76/0x90 tty_ldisc_flush+0x22/0x40 vt_ioctl+0x5a7/0x10b0 ? n_tty_ioctl_helper+0x27/0x110 tty_ioctl+0xef/0x8c0 do_vfs_ioctl+0xa7/0x5e0 ? __audit_syscall_entry+0xaf/0x100 ? syscall_trace_enter+0x1d0/0x2b0 SyS_ioctl+0x79/0x90 do_syscall_64+0x6c/0x1b0 entry_SYSCALL64_slow_path+0x25/0x25 n_tty_flush_buffer --->tty->disc_data is OK ->reset_buffer_flags -->tty->disc_data is NULL Signed-off-by: Yan.Gao <gao.yanB@h3c.com> Reviewed-by: Xianting Tian <tian.xianting@h3c.com> Link: https://lore.kernel.org/r/20201210022507.30729-1-gao.yanB@h3c.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-07drivers:tty:pty: Fix a race causing data loss on closeCorey Minyard2-4/+16
Remove the tty_vhangup() from the pty code and just release the redirect. The tty_vhangup() results in data loss and data out of order issues. If you write to a pty master an immediately close the pty master, the receiver might get a chunk of data dropped, but then receive some later data. That's obviously something rather unexpected for a user. It certainly confused my test program. It turns out that tty_vhangup() on the slave pty gets called from pty_close(), and that causes the data on the slave side to be flushed, but due to races more data can be copied into the slave side's buffer after that. Consider the following sequence: thread1 thread2 thread3 ------- ------- ------- | |-write data into buffer, | | n_tty buffer is filled | | along with other buffers | |-pty_close(master) | |--tty_vhangup(slave) | |---tty_ldisc_hangup() | |----n_tty_flush_buffer() | |-----reset_buffer_flags() |-n_tty_read() | |--up_read(&tty->termios_rwsem); | |------down_read(&tty->termios_rwsem) | |------clear n_tty buffer contents | |------up_read(&tty->termios_rwsem) |--tty_buffer_flush_work() | |--schedules work calling | | flush_to_ldisc() | | |-flush_to_ldisc() | |--receive_buf() | |---tty_port_default_receive_buf() | |----tty_ldisc_receive_buf() | |-----n_tty_receive_buf2() | |------n_tty_receive_buf_common() | |-------down_read(&tty->termios_rwsem) | |-------__receive_buf() | | copies data into n_tty buffer | |-------up_read(&tty->termios_rwsem) |--down_read(&tty->termios_rwsem) |--copy buffer data to user >From this sequence, you can see that thread2 writes to the buffer then only clears the part of the buffer in n_tty. The n_tty receive buffer code then copies more data into the n_tty buffer. But part of the vhangup, releasing the redirect, is still required to avoid issues with consoles running on pty slaves. So do that. As far as I can tell, that is all that should be required. Signed-off-by: Corey Minyard <cminyard@mvista.com> Link: https://lore.kernel.org/r/20201124004902.1398477-3-minyard@acm.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-07tty: Export redirect releaseCorey Minyard1-8/+24
This will be required by the pty code when it removes tty_vhangup() on master close. Signed-off-by: Corey Minyard <cminyard@mvista.com> Link: https://lore.kernel.org/r/20201124004902.1398477-2-minyard@acm.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-07serial: stm32: update transmission complete error message in shutdownErwan Le Ray1-1/+2
The transmission complete error message provides the status of the ISR_USART_TC bit. This bit, when set, indicates that the transmission has not been completed. The bit status indication is not a very understandable information. The error message sent on console should indicate that the transmission is not complete, instead of providing USART_TC bit status. Update the error message and add a comment for better understanding. Signed-off-by: Erwan Le Ray <erwan.leray@foss.st.com> Link: https://lore.kernel.org/r/20210106162203.28854-9-erwan.leray@foss.st.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>