user/sven/linux.git/include/linux/tty_flip.h, branch v6.4.5

tty: Convert tty_buffer flags to bool

2022-11-09T12:02:16Z

The struct tty_buffer has flags which is only used for storing TTYB_NORMAL. There is also a few quite confusing operations for checking the presense of TTYB_NORMAL. Simplify things by converting flags to bool. Despite the name remaining the same, the meaning of "flags" is altered slightly by this change. Previously it referred to flags of the buffer (only TTYB_NORMAL being used as a flag). After this change, flags tell whether the buffer contains/should be allocated with flags array along with character data array. It is much more suitable name that TTYB_NORMAL was for this purpose, thus the name remains. Signed-off-by: Ilpo Järvinen Link: https://lore.kernel.org/r/20221019105504.16800-1-ilpo.jarvinen@linux.intel.com Signed-off-by: Greg Kroah-Hartman

tty: drop tty_schedule_flip()

2021-11-25T17:35:23Z

Since commit a9c3f68f3cd8d (tty: Fix low_latency BUG) in 2014, tty_flip_buffer_push() is only a wrapper to tty_schedule_flip(). All users were converted in the previous patches, so remove tty_schedule_flip() completely while inlining its body into tty_flip_buffer_push(). One less exported function. Reviewed-by: Johan Hovold Signed-off-by: Jiri Slaby Link: https://lore.kernel.org/r/20211122111648.30379-4-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

tty: remove extern from functions in tty headers

2021-09-22T14:59:13Z

After the recent headers cleanup, some function declarations still have extern before them. It is superfluous (for function declarations), so remove extern from those which still have it. This unifies them with the rest of the files. Signed-off-by: Jiri Slaby Link: https://lore.kernel.org/r/20210914091134.17426-3-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

tty: tty_flip.h needs only tty_buffer and tty_port

2021-07-27T10:12:08Z

tty_flip.h currently includes whole tty.h. In fact, it needs only tty_buffer and tty_port definitions. Provided, we separated tty_buffer and tty_port into separate headers in the previous patch, we can make tty_flip.h to include only much lighter tty_buffer.h and tty_port.h. Signed-off-by: Jiri Slaby Link: https://lore.kernel.org/r/20210723103147.18250-9-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

tty: move tty_ldisc_receive_buf to tty_flip.h

2021-07-27T10:12:07Z

It's the only remaining tty_buffer.c prototype residing in tty.h. Move it along others to tty_flip.h. Signed-off-by: Jiri Slaby Link: https://lore.kernel.org/r/20210723103147.18250-6-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

tty: make linux/tty_flip.h self-contained

2021-06-25T07:58:51Z

If someone includes linux/tty_flip.h before linux/tty.h, they see many compiler errors like: include/linux/tty_flip.h:23:30: error: invalid use of undefined type 'struct tty_port' include/linux/tty_flip.h:26:14: error: invalid use of undefined type 'struct tty_buffer' tty_flip.h actually lexicographically sorts before tty.h. So if people sort includes (as I tried in amiserial), the compilation suddenly breaks. Solve this by including linux/tty.h from linux/tty_flip.h, so that everything is defined as needed. Another alternative would be to uninline tty_insert_flip_char and just insert forward declarations of tty_port and tty_buffer structs into tty_flip.h as that inline is the only real user. But that would mean slowing down the fast path without any good reason. (Provided the fix is that easy and there were no real problems with this until now.) Signed-off-by: Jiri Slaby Link: https://lore.kernel.org/r/20210625073511.4514-1-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

tty: make tty_buffer_space_avail return uint

2021-05-13T16:29:11Z

tty_buffer_space_avail returns values >= 0, so make it clear by the return type. Signed-off-by: Jiri Slaby Cc: Joel Stanley Link: https://lore.kernel.org/r/20210505091928.22010-25-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02T10:10:55Z

Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart Reviewed-by: Philippe Ombredanne Reviewed-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

tty: improve tty_insert_flip_char() fast path

2017-07-30T14:52:19Z

kernelci.org reports a crazy stack usage for the VT code when CONFIG_KASAN is enabled: drivers/tty/vt/keyboard.c: In function 'kbd_keycode': drivers/tty/vt/keyboard.c:1452:1: error: the frame size of 2240 bytes is larger than 2048 bytes [-Werror=frame-larger-than=] The problem is that tty_insert_flip_char() gets inlined many times into kbd_keycode(), and also into other functions, and each copy requires 128 bytes for stack redzone to check for a possible out-of-bounds access on the 'ch' and 'flags' arguments that are passed into tty_insert_flip_string_flags as a variable-length string. This introduces a new __tty_insert_flip_char() function for the slow path, which receives the two arguments by value. This completely avoids the problem and the stack usage goes back down to around 100 bytes. Without KASAN, this is also slightly better, as we don't have to spill the arguments to the stack but can simply pass 'ch' and 'flag' in registers, saving a few bytes in .text for each call site. This should be backported to linux-4.0 or later, which first introduced the stack sanitizer in the kernel. Cc: stable@vger.kernel.org Fixes: c420f167db8c ("kasan: enable stack instrumentation") Signed-off-by: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman

tty: Halve flip buffer GFP_ATOMIC memory consumption

2013-12-09T19:09:24Z

tty flip buffers use GFP_ATOMIC allocations for received data which is to be processed by the line discipline. For each byte received, an extra byte is used to indicate the error status of that byte. Instead, if the received data is error-free, encode the entire buffer without status bytes. Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman