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* dax,ext2: replace XIP read and write with DAX I/OMatthew Wilcox2015-02-168-245/+214
| | | | | | | | | | | | | | | | | | | | | Use the generic AIO infrastructure instead of custom read and write methods. In addition to giving us support for AIO, this adds the missing locking between read() and truncate(). Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Andreas Dilger <andreas.dilger@intel.com> Cc: Boaz Harrosh <boaz@plexistor.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Dave Chinner <david@fromorbit.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* vfs,ext2: introduce IS_DAX(inode)Matthew Wilcox2015-02-164-12/+24
| | | | | | | | | | | | | | | | | | | | | Use an inode flag to tag inodes which should avoid using the page cache. Convert ext2 to use it instead of mapping_is_xip(). Prevent I/Os to files tagged with the DAX flag from falling back to buffered I/O. Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andreas Dilger <andreas.dilger@intel.com> Cc: Boaz Harrosh <boaz@plexistor.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Dave Chinner <david@fromorbit.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: allow page fault handlers to perform the COWMatthew Wilcox2015-02-162-9/+33
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently COW of an XIP file is done by first bringing in a read-only mapping, then retrying the fault and copying the page. It is much more efficient to tell the fault handler that a COW is being attempted (by passing in the pre-allocated page in the vm_fault structure), and allow the handler to perform the COW operation itself. The handler cannot insert the page itself if there is already a read-only mapping at that address, so allow the handler to return VM_FAULT_LOCKED and set the fault_page to be NULL. This indicates to the MM code that the i_mmap_lock is held instead of the page lock. Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Andreas Dilger <andreas.dilger@intel.com> Cc: Boaz Harrosh <boaz@plexistor.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Dave Chinner <david@fromorbit.com> Cc: Jan Kara <jack@suse.cz> Cc: Jens Axboe <axboe@kernel.dk> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: fix XIP fault vs truncate raceMatthew Wilcox2015-02-162-2/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | DAX is a replacement for the variation of XIP currently supported by the ext2 filesystem. We have three different things in the tree called 'XIP', and the new focus is on access to data rather than executables, so a name change was in order. DAX stands for Direct Access. The X is for eXciting. The new focus on data access has resulted in more careful attention to races that exist in the current XIP code, but are not hit by the use-case that it was designed for. XIP's architecture worked fine for ext2, but DAX is architected to work with modern filsystems such as ext4 and XFS. DAX is not intended for use with btrfs; the value that btrfs adds relies on manipulating data and writing data to different locations, while DAX's value is for write-in-place and keeping the kernel from touching the data. DAX was developed in order to support NV-DIMMs, but it's become clear that its usefuless extends beyond NV-DIMMs and there are several potential customers including the tracing machinery. Other people want to place the kernel log in an area of memory, as long as they have a BIOS that does not clear DRAM on reboot. Patch 1 is a bug fix, probably worth including in 3.18. Patches 2 & 3 are infrastructure for DAX. Patches 4-8 replace the XIP code with its DAX equivalents, transforming ext2 to use the DAX code as we go. Note that patch 10 is the Documentation patch. Patches 9-15 clean up after the XIP code, removing the infrastructure that is no longer needed and renaming various XIP things to DAX. Most of these patches were added after Jan found things he didn't like in an earlier version of the ext4 patch ... that had been copied from ext2. So ext2 i being transformed to do things the same way that ext4 will later. The ability to mount ext2 filesystems with the 'xip' option is retained, although the 'dax' option is now preferred. Patch 16 adds some DAX infrastructure to support ext4. Patch 17 adds DAX support to ext4. It is broadly similar to ext2's DAX support, but it is more efficient than ext4's due to its support for unwritten extents. Patch 18 is another cleanup patch renaming XIP to DAX. My thanks to Mathieu Desnoyers for his reviews of the v11 patchset. Most of the changes below were based on his feedback. This patch (of 18): Pagecache faults recheck i_size after taking the page lock to ensure that the fault didn't race against a truncate. We don't have a page to lock in the XIP case, so use i_mmap_lock_read() instead. It is locked in the truncate path in unmap_mapping_range() after updating i_size. So while we hold it in the fault path, we are guaranteed that either i_size has already been updated in the truncate path, or that the truncate will subsequently call zap_page_range_single() and so remove the mapping we have just inserted. There is a window of time in which i_size has been reduced and the thread has a mapping to a page which will be removed from the file, but this is harmless as the page will not be allocated to a different purpose before the thread's access to it is revoked. [akpm@linux-foundation.org: switch to i_mmap_lock_read(), add comment in unmap_single_vma()] Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Andreas Dilger <andreas.dilger@intel.com> Cc: Boaz Harrosh <boaz@plexistor.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Dave Chinner <david@fromorbit.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* arm: dts: zynq: update isl9305 compatible string to use isil vendor prefixArnaud Ebalard2015-02-161-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | "isil" and "isl" prefixes are used at various locations inside the kernel to reference Intersil corporation. This patch is part of a series fixing those locations were "isl" is used in compatible strings to use the now expected "isil" prefix instead (NASDAQ symbol for Intersil and most used version). Note: isl9305 is an I2C device so the patch does not in fact currently depend on the introduction of "isil"-based compatible string in isl9305 driver (provided by another patch) because I2C core does not check the prefix yet. Signed-off-by: Arnaud Ebalard <arno@natisbad.org> Cc: Rob Herring <robh+dt@kernel.org> Cc: Pawel Moll <pawel.moll@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Ian Campbell <ijc+devicetree@hellion.org.uk> Cc: Kumar Gala <galak@codeaurora.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Stephen Warren <swarren@wwwdotorg.org> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Alexandre Courbot <gnurou@gmail.com> Cc: Uwe Kleine-Knig <uwe@kleine-koenig.org> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Peter Huewe <peter.huewe@infineon.com> Cc: Linus Walleij <linus.walleij@linaro.org> Cc: Mark Brown <broonie@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Darshana Padmadas <darshanapadmadas@gmail.com> Cc: Grant Likely <grant.likely@linaro.org> Cc: Rob Landley <rob@landley.net> Cc: Jason Cooper <jason@lakedaemon.net> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> Cc: Uwe Kleine-König <uwe@kleine-koenig.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* staging: iio: isl29028: deprecate use of isl in compatible string for isilArnaud Ebalard2015-02-161-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | "isil" and "isl" prefixes are used at various locations inside the kernel to reference Intersil corporation. This patch is part of a series fixing those locations were "isl" is used in compatible strings to use the now expected "isil" prefix instead (NASDAQ symbol for Intersil and most used version). The old compatible string is kept for backward compatibility. Signed-off-by: Arnaud Ebalard <arno@natisbad.org> Cc: Rob Herring <robh+dt@kernel.org> Cc: Pawel Moll <pawel.moll@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Ian Campbell <ijc+devicetree@hellion.org.uk> Cc: Kumar Gala <galak@codeaurora.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Stephen Warren <swarren@wwwdotorg.org> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Alexandre Courbot <gnurou@gmail.com> Cc: Uwe Kleine-Knig <uwe@kleine-koenig.org> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Peter Huewe <peter.huewe@infineon.com> Cc: Linus Walleij <linus.walleij@linaro.org> Cc: Mark Brown <broonie@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Darshana Padmadas <darshanapadmadas@gmail.com> Cc: Grant Likely <grant.likely@linaro.org> Cc: Rob Landley <rob@landley.net> Cc: Jason Cooper <jason@lakedaemon.net> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> Cc: Uwe Kleine-König <uwe@kleine-koenig.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* rtc: isl12057: deprecate use of isl in compatible string for isilArnaud Ebalard2015-02-161-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | "isil" and "isl" prefixes are used at various locations inside the kernel to reference Intersil corporation. This patch is part of a series fixing those locations were "isl" is used in compatible strings to use the now expected "isil" prefix instead (NASDAQ symbol for Intersil and most used version). The old compatible string is kept for backward compatibility. Signed-off-by: Arnaud Ebalard <arno@natisbad.org> Cc: Rob Herring <robh+dt@kernel.org> Cc: Pawel Moll <pawel.moll@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Ian Campbell <ijc+devicetree@hellion.org.uk> Cc: Kumar Gala <galak@codeaurora.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Stephen Warren <swarren@wwwdotorg.org> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Alexandre Courbot <gnurou@gmail.com> Cc: Uwe Kleine-Knig <uwe@kleine-koenig.org> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Peter Huewe <peter.huewe@infineon.com> Cc: Linus Walleij <linus.walleij@linaro.org> Cc: Mark Brown <broonie@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Darshana Padmadas <darshanapadmadas@gmail.com> Cc: Grant Likely <grant.likely@linaro.org> Cc: Rob Landley <rob@landley.net> Cc: Jason Cooper <jason@lakedaemon.net> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> Cc: Uwe Kleine-König <uwe@kleine-koenig.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* rtc: isl12022: deprecate use of isl in compatible string for isilArnaud Ebalard2015-02-161-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | "isil" and "isl" prefixes are used at various locations inside the kernel to reference Intersil corporation. This patch is part of a series fixing those locations were "isl" is used in compatible strings to use the now expected "isil" prefix instead (NASDAQ symbol for Intersil and most used version). The old compatible string is kept for backward compatibility. Signed-off-by: Arnaud Ebalard <arno@natisbad.org> Cc: Rob Herring <robh+dt@kernel.org> Cc: Pawel Moll <pawel.moll@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Ian Campbell <ijc+devicetree@hellion.org.uk> Cc: Kumar Gala <galak@codeaurora.org> Cc: Russell King <linux@arm.linux.org.uk> Cc: Stephen Warren <swarren@wwwdotorg.org> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Alexandre Courbot <gnurou@gmail.com> Cc: Uwe Kleine-Knig <uwe@kleine-koenig.org> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Peter Huewe <peter.huewe@infineon.com> Cc: Linus Walleij <linus.walleij@linaro.org> Cc: Mark Brown <broonie@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Darshana Padmadas <darshanapadmadas@gmail.com> Cc: Grant Likely <grant.likely@linaro.org> Cc: Rob Landley <rob@landley.net> Cc: Jason Cooper <jason@lakedaemon.net> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> Cc: Uwe Kleine-König <uwe@kleine-koenig.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge tag 'cris-for-3.20' of ↵Linus Torvalds2015-02-156-76/+111
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jesper/cris Pull CRIS changes from Jesper Nilsson. * tag 'cris-for-3.20' of git://git.kernel.org/pub/scm/linux/kernel/git/jesper/cris: CRIS: Whitespace cleanup CRIS: macro whitespace fixes in uaccess.h CRIS: uaccess: fix sparse errors CRISv32: Remove unnecessary KERN_INFO from sync_serial CRIS: Fix missing NR_CPUS in menuconfig CRISv32: Avoid warning of unused variable CRIS: Avoid warning in cris mm/fault.c CRIS: Export csum_partial_copy_nocheck
| * CRIS: Whitespace cleanupJesper Nilsson2015-02-141-31/+52
| | | | | | | | | | | | No functional change, just clean up the most obvious. Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
| * CRIS: macro whitespace fixes in uaccess.hMichael S. Tsirkin2015-02-141-55/+58
| | | | | | | | | | | | | | | | | | | | | | While working on arch/cris/include/asm/uaccess.h, I noticed that some macros within this header are made harder to read because they violate a coding style rule: space is missing after comma. Fix it up. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
| * CRIS: uaccess: fix sparse errorsMichael S. Tsirkin2015-02-141-2/+2
| | | | | | | | | | | | | | | | | | | | | | virtio wants to read bitwise types from userspace using get_user. At the moment this triggers sparse errors, since the value is passed through an integer. Fix that up using __force. Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
| * CRISv32: Remove unnecessary KERN_INFO from sync_serialMasanari Iida2015-02-141-2/+2
| | | | | | | | | | | | | | Remove unnecessary KERN_INFO in sync_serial.c Signed-off-by: Masanari Iida <standby24x7@gmail.com> Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
| * CRIS: Fix missing NR_CPUS in menuconfigJesper Nilsson2015-01-291-0/+4
| | | | | | | | | | | | | | | | | | The time Kconfig expects that NR_CPUS is defined. This patch removes this config warning: "kernel/time/Kconfig:163:warning: range is invalid" Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
| * CRISv32: Avoid warning of unused variableJesper Nilsson2015-01-291-0/+4
| | | | | | | | | | | | | | | | | | | | Avoids the warning about: warning: 'bite_in_progress' defined but not used [-Wunused-variable] Variable is only used if the Kconfig CONFIG_ETRAX_WATCHDOG_NICE_DOGGY is set. Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
| * CRIS: Avoid warning in cris mm/fault.cJesper Nilsson2015-01-291-1/+3
| | | | | | | | | | | | | | Move declaration of waitqueue to beginning of block, avoids warning about mixing declarations and code. Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
| * CRIS: Export csum_partial_copy_nocheckJesper Nilsson2015-01-291-0/+1
| | | | | | | | | | | | | | | | | | Allows that symbol to be used in modules, and fixes the following on allmodconfig: ERROR: "csum_partial_copy_nocheck" [net/ipv6/ipv6.ko] undefined! Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
* | Merge tag 'tty-3.20-rc1' of ↵Linus Torvalds2015-02-1573-1910/+4523
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty Pull tty/serial driver patches from Greg KH: "Here's the big tty/serial driver update for 3.20-rc1. Nothing huge here, just lots of driver updates and some core tty layer fixes as well. All have been in linux-next with no reported issues" * tag 'tty-3.20-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (119 commits) serial: 8250: Fix UART_BUG_TXEN workaround serial: driver for ETRAX FS UART tty: remove unused variable sprop serial: of-serial: fetch line number from DT serial: samsung: earlycon support depends on CONFIG_SERIAL_SAMSUNG_CONSOLE tty/serial: serial8250_set_divisor() can be static tty/serial: Add Spreadtrum sc9836-uart driver support Documentation: DT: Add bindings for Spreadtrum SoC Platform serial: samsung: remove redundant interrupt enabling tty: Remove external interface for tty_set_termios() serial: omap: Fix RTS handling serial: 8250_omap: Use UPSTAT_AUTORTS for RTS handling serial: core: Rework hw-assisted flow control support tty/serial: 8250_early: Add support for PXA UARTs tty/serial: of_serial: add support for PXA/MMP uarts tty/serial: of_serial: add DT alias ID handling serial: 8250: Prevent concurrent updates to shadow registers serial: 8250: Use canary to restart console after suspend serial: 8250: Refactor XR17V35X divisor calculation serial: 8250: Refactor divisor programming ...
| * | serial: 8250: Fix UART_BUG_TXEN workaroundPeter Hurley2015-02-071-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | UARTs which do not trigger THRE interrupt if the fifo is already empty when the interrupt is enabled need tx primed manually. These UARTs are identified by the UART_BUG_TXEN flag to enable the required workaround. However, the current workaround is broken; if the fifo is already empty but the shifter is still transmitting, then serial8250_tx_chars() will not be called but no further THRE interrupt will occur, and tx will stall. The appropriate check is for fifo empty (THRE), not transmitter empty (TEMT). Signed-off-by: Dick Hollenbeck <dick@softplc.com> [pjh: rewrote commit log] Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: driver for ETRAX FS UARTNiklas Cassel2015-02-074-0/+1010
| | | | | | | | | | | | | | | | | | | | | | | | This is the last missing piece to get a kernel booting to a prompt in qemu-cris. Signed-off-by: Niklas Cassel <nks@flawful.org> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | tty: remove unused variable spropFabian Frederick2015-02-031-1/+0
| | | | | | | | | | | | | | | | | | | | | | | | sprop is unused in find_console_handle() since commit a752ee56ad84 ("tty: Update hypervisor tty drivers to use core stdout parsing code.") Signed-off-by: Fabian Frederick <fabf@skynet.be> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: of-serial: fetch line number from DTLucas Stach2015-02-031-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The general agreed way to specify a fixed line number for a serial console is to provide a "serial" alias in the devicetree. Start parsing this property in of_serial. Signed-off-by: Lucas Stach <dev@lynxeye.de> Acked-by: Olof Johansson <olof@lixom.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: samsung: earlycon support depends on CONFIG_SERIAL_SAMSUNG_CONSOLEMarek Szyprowski2015-02-021-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | EarlyCon support depends on serial console infrastructure, so the code implementing it should depend on CONFIG_SERIAL_SAMSUNG_CONSOLE. This patch fixes the following build break: CC [M] drivers/tty/serial/samsung.o drivers/tty/serial/samsung.c:2468:1: error: expected declaration specifiers or ‘...’ before string constant drivers/tty/serial/samsung.c:2468:1: error: expected declaration specifiers or ‘...’ before ‘s3c2410_setup_earlycon’ drivers/tty/serial/samsung.c:2487:1: error: expected declaration specifiers or ‘...’ before string constant drivers/tty/serial/samsung.c:2487:1: error: expected declaration specifiers or ‘...’ before ‘s3c2412_setup_earlycon’ drivers/tty/serial/samsung.c:2488:1: error: expected declaration specifiers or ‘...’ before string constant drivers/tty/serial/samsung.c:2488:1: error: expected declaration specifiers or ‘...’ before ‘s3c2440_setup_earlycon’ drivers/tty/serial/samsung.c:2489:1: error: expected declaration specifiers or ‘...’ before string constant drivers/tty/serial/samsung.c:2489:1: error: expected declaration specifiers or ‘...’ before ‘s3c6400_setup_earlycon’ drivers/tty/serial/samsung.c:2506:1: error: expected declaration specifiers or ‘...’ before string constant drivers/tty/serial/samsung.c:2506:1: error: expected declaration specifiers or ‘...’ before ‘s5pv210_setup_earlycon’ drivers/tty/serial/samsung.c:2507:1: error: expected declaration specifiers or ‘...’ before string constant drivers/tty/serial/samsung.c:2507:1: error: expected declaration specifiers or ‘...’ before ‘exynos4210_setup_earlycon’ drivers/tty/serial/samsung.c:2468:1: warning: ‘s3c2410_setup_earlycon’ defined but not used [-Wunused-function] drivers/tty/serial/samsung.c:2487:1: warning: ‘s3c2412_setup_earlycon’ defined but not used [-Wunused-function] drivers/tty/serial/samsung.c:2488:1: warning: ‘s3c2440_setup_earlycon’ defined but not used [-Wunused-function] drivers/tty/serial/samsung.c:2489:1: warning: ‘s3c6400_setup_earlycon’ defined but not used [-Wunused-function] drivers/tty/serial/samsung.c:2506:1: warning: ‘s5pv210_setup_earlycon’ defined but not used [-Wunused-function] drivers/tty/serial/samsung.c:2507:1: warning: ‘exynos4210_setup_earlycon’ defined but not used [-Wunused-function] make[3]: *** [drivers/tty/serial/samsung.o] Error 1 Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | tty/serial: serial8250_set_divisor() can be statickbuild test robot2015-02-021-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | drivers/tty/serial/8250/8250_core.c:2503:6: sparse: symbol 'serial8250_set_divisor' was not declared. Should it be static? Signed-off-by: Fengguang Wu <fengguang.wu@intel.com> Cc: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | tty/serial: Add Spreadtrum sc9836-uart driver supportChunyan Zhang2015-02-024-0/+815
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a full sc9836-uart driver for SC9836 SoC which is based on the spreadtrum sharkl64 platform. This driver also support earlycon. Originally-by: Lanqing Liu <lanqing.liu@spreadtrum.com> Signed-off-by: Orson Zhai <orson.zhai@spreadtrum.com> Signed-off-by: Chunyan Zhang <chunyan.zhang@spreadtrum.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | Documentation: DT: Add bindings for Spreadtrum SoC PlatformChunyan Zhang2015-02-023-0/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Adds Spreadtrum's prefix "sprd" to vendor-prefixes file. Adds the devicetree binding documentations for Spreadtrum's sc9836-uart and SC9836 SoC based on the Sharkl64 Platform which is a 64-bit SoC Platform of Spreadtrum. Signed-off-by: Chunyan Zhang <chunyan.zhang@spreadtrum.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: samsung: remove redundant interrupt enablingRobert Baldyga2015-02-021-8/+1
| | | | | | | | | | | | | | | | | | | | | | | | Function s3c24xx_serial_start_tx_pio() enables interrupts if needed, so we don't have to (or even we shouldn't) enable them before. Signed-off-by: Robert Baldyga <r.baldyga@samsung.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | tty: Remove external interface for tty_set_termios()Peter Hurley2015-02-023-16/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | tty_set_termios() is an internal helper intended for file scope use. UART drivers which are capable of driving the RTS pin must properly handle the tiocmset() method, regardless of termios settings. A failure to do so is a UART driver bug and should be fixed there. Do not use this interface to workaround UART driver bugs. Cc: Johan Hedberg <johan.hedberg@gmail.com> Cc: <linux-bluetooth@vger.kernel.org> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Acked-by: Marcel Holtmann <marcel@holtmann.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: omap: Fix RTS handlingPeter Hurley2015-02-021-8/+14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The OMAP UART ignores MCR[1] (ie., RTS) when in autoRTS mode. This makes it impossible for either the serial core or userspace to manually flow control the sender. Disable autoRTS mode when RTS is lowered and restore the previous mode when RTS is raised. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: 8250_omap: Use UPSTAT_AUTORTS for RTS handlingPeter Hurley2015-02-021-9/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 88838d3112702 ("serial: omap_8250: Fix RTS handling") fixed RTS pin control when in autoRTS mode. New support added in "serial: core: Rework hw-assisted flow control support" enables a much simpler approach; rather than masking out autoRTS whenever writing the EFR register, use the UPSTAT_* mode to determine if autoRTS should be enabled when raising RTS (in omap8250_set_mctrl()). Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: core: Rework hw-assisted flow control supportPeter Hurley2015-02-024-52/+59
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | hw-assisted flow control support was added to the serial core in v3.8 with commits, dba05832cbe4f ("SERIAL: core: add hardware assisted h/w flow control support") 2cbacafd7af0f ("SERIAL: core: add hardware assisted s/w flow control support") 9aba8d5b01119 ("SERIAL: core: add throttle/unthrottle callbacks for hardware assisted flow control") Since then, additional requirements for serial core support have arisen. Specifically, 1. Separate tx and rx flow control settings for UARTs which only support tx flow control (ie., autoCTS). 2. Disable sw-assisted CTS flow control in autoCTS mode 3. Support for RTS flow control by serial core and userspace in autoRTS mode Distinguish mode from capability; introduce UPSTAT_AUTORTS, UPSTAT_AUTOCTS and UPSTAT_AUTOXOFF which, when set by the uart driver, enable serial core support for hw-assisted rx, hw-assisted tx and hw-assisted in-band/IXOFF rx flow control, respectively. [Note: hw-assisted in-band/IXON tx flow control does not require serial core support/intervention and can be enabled by the uart driver when required.] These modes must be set/reset in the driver's set_termios() method, based on termios settings, and thus can be safely queried in any context in which one of the port lock, port mutex or termios rwsem are held. Set these modes in the 2 in-tree drivers, omap-serial and 8250_omap, which currently use UPF_HARD_FLOW/UPF_SOFT_FLOW support. Retain UPF_HARD_FLOW and UPF_SOFT_FLOW as capabilities; re-define UPF_HARD_FLOW as both UPF_AUTO_RTS and UPF_AUTO_CTS to allow for distinct and separate rx and tx flow control capabilities. Disable sw-assisted CTS flow control when UPSTAT_AUTOCTS is enabled. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | tty/serial: 8250_early: Add support for PXA UARTsRob Herring2015-02-021-3/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The PXA variant of the 8250 UART adds a UART enable bit which must not be cleared. Make the earlycon support maintain this bit if it is set. This implies some initialization of the UART, but we cannot unconditionally set the bit as some other variants require this bit to be clear for other functions. Signed-off-by: Rob Herring <robh@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jslaby@suse.cz> Cc: linux-serial@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | tty/serial: of_serial: add support for PXA/MMP uartsRob Herring2015-02-021-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add mrvl,pxa-uart and mrvl,mmp-uart compatible strings for the of_serial driver. These are 8250 variants which have a port type of PORT_XSCALE. There is also the serial driver pxa.c with these compatible strings already. However, it can be replaced with the common 8250 driver. It has some issues like it cannot coexist with the 8250 driver due to tty name collision. That also means adding these compatible strings here should not case a problem. Signed-off-by: Rob Herring <robh@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jslaby@suse.cz> Cc: linux-serial@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | tty/serial: of_serial: add DT alias ID handlingRob Herring2015-02-021-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add support for alias parsing from the DT. This allows for consistent tty numbering. Signed-off-by: Rob Herring <robh@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jslaby@suse.cz> Cc: linux-serial@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: 8250: Prevent concurrent updates to shadow registersPeter Hurley2015-02-021-9/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | The port shadow registers, ->fcr and ->mcr, must be protected from concurrent updates. Relocate the shadow register updates in serial8250_do_set_termios() to the port lock critical section. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: 8250: Use canary to restart console after suspendPeter Hurley2015-02-022-1/+37
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When using no_console_suspend, the serial console may be powered off anyway during system sleep. Upon resume, the port may be in its default power-on state, but is expected to continue console i/o before the device has received its pm callback. The resultant garbage i/o can cause all kinds of havoc on the remote end. Use the scratch register as a canary to discover if the console has been powered-off. Write a non-zero value to the scratch register at port suspend and reprogram the port before any console i/o if the scratch register != canary before port resume. This workaround is disabled for omap_8250 (which uses different divisor programming). Credit to Doug Anderson <dianders@chromium.org> for the idea of using the scratch register canary to discover port power-down. Cc: Doug Anderson <dianders@chromium.org> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: 8250: Refactor XR17V35X divisor calculationPeter Hurley2015-02-021-22/+30
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Exar XR17V35X PCIe uarts support a 4-bit fractional divisor register. Refactor the divisor calculation from the divisor programming. Allow a fractional result from serial8250_get_divisor() and pass this result to serial8250_dl_write(). Simplify the calculation for quot and quot_frac. This was verified to be identical to the results of the original calculation with a test jig. NB: The results were also compared with the divisor value chart on pg 33 of the Exar XR17V352 datasheet, rev 1.0.3, here: http://www.exar.com/common/content/document.ashx?id=1585 which differs from the calculated values by 1 in the fractional result. This is because the calculated values are still rounded in the fractional result, whereas the table values are truncated. Note that the data error rate % values in the datasheet are for rounded fractional results, as the truncated fractional results have more error. Cc: Joe Schultz <jschultz@xes-inc.com> Cc: Aaron Sierra <asierra@xes-inc.com> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: 8250: Refactor divisor programmingPeter Hurley2015-02-021-39/+48
| | | | | | | | | | | | | | | | | | | | | | | | | | | Refactor divisor register programming into a new function, serial8250_set_divisor; this allows serial console to reinitialize early after resume from suspend. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: 8250: Refactor LCR computationPeter Hurley2015-02-021-11/+21
| | | | | | | | | | | | | | | | | | | | | | | | Refactor the computation of the LCR register value from termios c_cflag into a new local function, serial8250_compute_lcr(). Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: 8250: Move UART_BUG_QUOT workaroundPeter Hurley2015-02-021-8/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The UART_BUG_QUOT workaround adjusts the divisor computed from the baud rate by serial8250_get_divisor(). Move the workaround into serial8250_get_divisor(), so that divisor-from-baud computation is encapsulated. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | tty: serial: men_z135_uart: Fix driver for changes in hardwareJohannes Thumshirn2015-02-021-46/+109
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 16z135 IP Core has changed so the driver needs to be updated to respect these changes. The following changes have been made: * Don't invert the 16z135 modem status register when reading. * Add module parameter to configure the (baud rate dependent) RX timeout. Character timeout in seconds = (timeout_reg * baud_reg * 4)/freq_reg. * Enable the handling of UART core's automatic flow control feature. When AFE is active disable generation of modem status IRQs. * Rework the handling of IRQs to be conform with newer FPGA versions and take precautions not to miss an interrupt because of the destructive read of the IIR register. * Correct men_z135_handle_modem_status(), MSR is stat_reg[15:8] not stat_reg[7:0] * Correct calling of uart_handle_{dcd,cts}_change() * Reset CLOCAL when CRTSCTS is set Signed-off-by: Johannes Thumshirn <johannes.thumshirn@men.de> Reviewed-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | serial: core: Simplify console suspend logic in uart_suspend_port()Peter Hurley2015-02-021-18/+17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When the uart port being suspended is a console and consoles are not suspending (kernel command line contains no_console_suspend), then no action is performed for that port, and the function can return early. If the function has not returned early, then one of the conditions is not true, so the expression (console_suspend_enabled || !uart_console(uport)) must be true and can be eliminated. Similarly, the expression (console_suspend_enabled && uart_console(uport)) simplifies to just uart_console(uport). Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | Specify PCI based UART for earlyprintkStuart R. Anderson2015-02-021-16/+166
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add support for specifying PCI based UARTs for earlyprintk using a syntax like "earlyprintk=pciserial,00:18.1,115200", where 00:18.1 is the BDF of a UART device. [Slightly tidied from Stuart's original patch] Signed-off-by: Alan Cox <alan@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | n_tty: Fix signal handling flushesPeter Hurley2015-02-023-15/+34
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRKINT and ISIG requires input and output flush when a signal char is received. However, the order of operations is significant since parallel i/o may be ongoing. Merge the signal handling for BRKINT with ISIG handling. Process the signal first. This ensures any ongoing i/o is aborted; without this, a waiting writer may continue writing after the flush occurs and after the signal char has been echoed. Write lock the termios_rwsem, which excludes parallel writers from pushing new i/o until after the output buffers are flushed; claiming the write lock is necessary anyway to exclude parallel readers while the read buffer is flushed. Subclass the termios_rwsem for ptys since the slave pty performing the flush may appear to reorder the termios_rwsem->tty buffer lock lock order; adding annotation clarifies that slave tty_buffer lock-> slave termios_rwsem -> master tty_buffer lock is a valid lock order. Flush the echo buffer. In this context, the echo buffer is 'output'. Otherwise, the output will appear discontinuous because the output buffer was cleared which contains older output than the echo buffer. Open-code the read buffer flush since the input worker does not need kicking (this is the input worker). Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | pty: Fix buffer flush deadlockPeter Hurley2015-02-023-1/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The pty driver does not clear its write buffer when commanded. This is to avoid an apparent deadlock between parallel flushes from both pty ends; specifically when handling either BRK or INTR input. However, parallel flushes from this source is not possible since the pty master can never be set to BRKINT or ISIG. Parallel flushes from other sources are possible but these do not threaten deadlocks. Annotate the tty buffer mutex for lockdep to represent the nested tty_buffer locking which occurs when the pty slave is processing input (its buffer mutex held) and receives INTR or BRK and acquires the linked tty buffer mutex via tty_buffer_flush(). Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | tty: Make lock subclasses available for other tty locksPeter Hurley2015-02-022-11/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Besides nested legacy_mutex locking which is required on pty pair teardown, other nested pty operations require lock subclassing. Move lock subclass definition to tty interface header, include/linux/tty.h, and document its use. Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | n_tty: Fix read buffer overwrite when no newlinePeter Hurley2015-02-021-30/+62
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In canon mode, the read buffer head will advance over the buffer tail if the input > 4095 bytes without receiving a line termination char. Discard additional input until a line termination is received. Before evaluating for overflow, the 'room' value is normalized for I_PARMRK and 1 byte is reserved for line termination (even in !icanon mode, in case the mode is switched). The following table shows the transform: actual buffer | 'room' value before overflow calc space avail | !I_PARMRK | I_PARMRK -------------------------------------------------- 0 | -1 | -1 1 | 0 | 0 2 | 1 | 0 3 | 2 | 0 4+ | 3 | 1 When !icanon or when icanon and the read buffer contains newlines, normalized 'room' values of -1 and 0 are clamped to 0, and 'overflow' is 0, so read_head is not adjusted and the input i/o loop exits (setting no_room if called from flush_to_ldisc()). No input is discarded since the reader does have input available to read which ensures forward progress. When icanon and the read buffer does not contain newlines and the normalized 'room' value is 0, then overflow and room are reset to 1, so that the i/o loop will process the next input char normally (except for parity errors which are ignored). Thus, erasures, signalling chars, 7-bit mode, etc. will continue to be handled properly. If the input char processed was not a line termination char, then the canon_head index will not have advanced, so the normalized 'room' value will now be -1 and 'overflow' will be set, which indicates the read_head can safely be reset, effectively erasing the last char processed. If the input char processed was a line termination, then the canon_head index will have advanced, so 'overflow' is cleared to 0, the read_head is not reset, and 'room' is cleared to 0, which exits the i/o loop (because the reader now have input available to read which ensures forward progress). Note that it is possible for a line termination to be received, and for the reader to copy the line to the user buffer before the input i/o loop is ready to process the next input char. This is why the i/o loop recomputes the room/overflow state with every input char while handling overflow. Finally, if the input data was processed without receiving a line termination (so that overflow is still set), the pty driver must receive a write wakeup. A pty writer may be waiting to write more data in n_tty_write() but without unthrottling here that wakeup will not arrive, and forward progress will halt. (Normally, the pty writer is woken when the reader reads data out of the buffer and more space become available). Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | n_tty: Fix PARMRK over-throttlingPeter Hurley2015-02-021-8/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If PARMRK is enabled, the available read buffer space computation is overly-pessimistic, which results in severely throttled i/o, even in the absence of parity errors. For example, if the 4k read buffer contains 1k processed data, the input worker will compute available space of 333 bytes, despite 3k being available. At 1365 chars of processed data, 0 space available is computed. *Divide remaining space* by 3, truncating down (if left == 2, left = 0). Reported-by: Christian Riesch <christian.riesch@omicron.at> Conflicts: drivers/tty/n_tty.c Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | n_tty: Fix unordered accesses to lockless read bufferPeter Hurley2015-02-021-53/+48
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add commit_head buffer index, which the producer-side publishes after input processing in non-canon mode. This ensures the consumer-side observes correctly-ordered writes in non-canonical mode (ie., the buffer data is written before the buffer index is advanced). Fix consumer-side uses of read_cnt() to use commit_head instead. Add required memory barriers to the tail index to guarantee the consumer-side has completed the loads before the producer-side begins writing new data. Open-code the producer-side receive_room() into the i/o loop. Remove no-longer-referenced receive_room(). Based on work by Christian Riesch <christian.riesch@omicron.at> Cc: Christian Riesch <christian.riesch@omicron.at> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| * | n_tty: Simplify throttle threshold calculationPeter Hurley2015-02-021-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The adjustments performed by receive_room() are to ensure a line termination can always be written to the read buffer. However, these adjustments are irrelevant to the throttle threshold (because the threshold < buffer limit). Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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