kernel/linux.git/drivers/s390/cio/css.h, branch v7.1

driver core: have match() callback in struct bus_type take a const *

2024-07-03T13:16:54+00:00

In the match() callback, the struct device_driver * should not be changed, so change the function callback to be a const *. This is one step of many towards making the driver core safe to have struct device_driver in read-only memory. Because the match() callback is in all busses, all busses are modified to handle this properly. This does entail switching some container_of() calls to container_of_const() to properly handle the constant *. For some busses, like PCI and USB and HV, the const * is cast away in the match callback as those busses do want to modify those structures at this point in time (they have a local lock in the driver structure.) That will have to be changed in the future if they wish to have their struct device * in read-only-memory. Cc: Rafael J. Wysocki Reviewed-by: Alex Elder Acked-by: Sumit Garg Link: https://lore.kernel.org/r/2024070136-wrongdoer-busily-01e8@gregkh Signed-off-by: Greg Kroah-Hartman

s390/cio: export extended channel-path-measurement data

2024-04-12T14:11:29+00:00

Add a per-CHPID binary sysfs attribute named "ext_measurement" that provides access to extended channel-path-measurement data for the associated channel path. Note that while not all channel-paths provide extended measurement data this attribute is created unconditionally for all channel paths because channel-path measurement capabilities might change during run-time. Reading from the attribute will only return data for channel-paths that support extended measurement data. Example: $ echo 1 > /sys/devices/css0/cm_enable $ xxd /sys/devices/css0/chp0.32/ext_measurement 00000000: 53e0 8002 0000 0095 0000 0000 59cc e034 S...........Y..4 00000010: 38b8 cc45 0000 0000 0000 0000 3e24 fe94 8..E........>$.. 00000020: 0000 0000 0000 0000 0000 0000 0000 0000 ................ 00000030: 0000 0000 0000 0000 0000 0000 0000 0000 ................ Reviewed-by: Vineeth Vijayan Tested-by: Vineeth Vijayan Acked-by: Heiko Carstens Signed-off-by: Peter Oberparleiter Signed-off-by: Alexander Gordeev

s390/cio: rework channel-utilization-block handling

2024-04-12T14:11:28+00:00

Convert channel-utilization-block (CUB) address variables from separate named fields to arrays of addresses. Also simplify error handling and introduce named constants. This is done in preparation of introducing additional CUBs. Note: With this change the __packed annotation of secm_area is required to prevent an alignment hole that would otherwise occur due to the switch from u32 to dma64_t. Reviewed-by: Vineeth Vijayan Acked-by: Heiko Carstens Signed-off-by: Peter Oberparleiter Signed-off-by: Alexander Gordeev

s390/cio: evaluate devices with non-operational paths

2023-01-22T17:42:34+00:00

css_schedule_reprobe() function calls the evaluation for CSS_EVAL_UNREG which is specific to the idset of unregistered subchannels. This evaluation was introduced because, previously, if the underlying device become not-accessible, the subchannel was unregistered. But, in the recent changes in cio,with the commit '2297791c92d0 s390/cio: dont unregister subchannel from child-drivers', we no longer unregister the subchannels just because of a non-operational device. This allows to have subchannels without any operational device connected on it. So, a css_schedule_reprobe function on unregistered subchannel does not have any effect. Change this functionality to evaluate the subchannels which does not have a working path to the device. This could be due the erroneous device or due to the erraneous path. Evaluate based on the values of OPM and PAM&POM. Here we introduced a new idset function,to keep I/O subchannels in the idset when the last seen status indicates that the device has no working path. A device has no working path if all available paths have been tried without success.A failed I/O attempt on a path is indicated as a 0 bit value in the POM mask. By looking at the POM mask bit values of available paths (1 in PAM) that Linux is supposed to use (1 in vary mask OPM), we can identify a non-working device as a device where the bit-wise and of the PAM, POM and OPM mask return 0. css_schedule_reprobe() is being used by dasd-driver and chsc-cio component. dasd driver, when it detects a change in the pathgroup, invokes the re-evaluation of the subchannel. And chsc-cio component upon a CRW event, (resource accessibility event). In both the cases, it makes much better sense to re-evalute the subchannel with no-valid path. Signed-off-by: Vineeth Vijayan Reported-by: Eric Farman Reviewed-by: Peter Oberparleiter Tested-by: Eric Farman Signed-off-by: Heiko Carstens

s390/cio: avoid excessive path-verification requests

2021-09-27T11:54:38+00:00

Currently when removing a device from cio_ignore list, we trigger a path-verification for all the subchannels available in the system. This could lead to path-verification requests on subchannels with an online device, which could cause unwanted delay. Instead of all the subchannels, trigger the path-verifications to those without an online device. Reported-by: Julian Wiedmann Fixes: 2297791c92d0 ("s390/cio: dont unregister subchannel from child-drivers") Signed-off-by: Vineeth Vijayan Reviewed-by: Peter Oberparleiter Signed-off-by: Heiko Carstens

s390/cio: Make struct css_driver::remove return void

2021-07-21T09:53:41+00:00

The driver core ignores the return value of css_remove() (because there is only little it can do when a device disappears) and all callbacks return 0 anyhow. So make it impossible for future drivers to return an unused error code by changing the remove prototype to return void. The real motivation for this change is the quest to make struct bus_type::remove return void, too. Reviewed-by: Cornelia Huck Acked-by: Vineeth Vijayan Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/20210713193522.1770306-3-u.kleine-koenig@pengutronix.de Signed-off-by: Greg Kroah-Hartman

s390/cio: remove pm support from css-bus driver

2020-12-02T17:19:25+00:00

The power-management functions are unused since the 'commit 394216275c7d ("s390: remove broken hibernate / power management support")'. Remove the unused pm callbacks from css-bus driver. Signed-off-by: Vineeth Vijayan Reviewed-by: Peter Oberparleiter Signed-off-by: Heiko Carstens

s390/cio: Helper functions to read CSSID, IID, and CHID

2020-09-15T20:21:46+00:00

Add helper functions to expose Channel Subsystem ID (CSSID), MIF Image Id (IID), Channel ID (CHID) and Channel Path ID (CHPID). These values are required by the qeth driver's exploitation of network- address-change-notifications to determine which entries belong to this interface. Store the Partition identifier in System log, as this may be used to map a Linux view to a Hardware view for debugging purpose. Signed-off-by: Alexandra Winter Reviewed-by: Vineeth Vijayan Signed-off-by: Julian Wiedmann Acked-by: Heiko Carstens Signed-off-by: David S. Miller

s390/css: reduce stsch calls

2018-07-17T05:27:55+00:00

Both css_evaluate_new_subchannel and cio_validate_subchannel used stsch and css_sch_is_valid to check for a valid device. Reduce stsch calls during subchannel evaluation by re-using schib data. Also the type/devno valid information is only checked once. Signed-off-by: Sebastian Ott Reviewed-by: Peter Oberparleiter Signed-off-by: Martin Schwidefsky

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

2017-11-02T10:10:55+00:00

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