linux/drivers/base, branch v5.6

drivers/base/memory.c: indicate all memory blocks as removable

2020-03-29T16:47:05Z

We see multiple issues with the implementation/interface to compute whether a memory block can be offlined (exposed via /sys/devices/system/memory/memoryX/removable) and would like to simplify it (remove the implementation). 1. It runs basically lockless. While this might be good for performance, we see possible races with memory offlining that will require at least some sort of locking to fix. 2. Nowadays, more false positives are possible. No arch-specific checks are performed that validate if memory offlining will not be denied right away (and such check will require locking). For example, arm64 won't allow to offline any memory block that was added during boot - which will imply a very high error rate. Other archs have other constraints. 3. The interface is inherently racy. E.g., if a memory block is detected to be removable (and was not a false positive at that time), there is still no guarantee that offlining will actually succeed. So any caller already has to deal with false positives. 4. It is unclear which performance benefit this interface actually provides. The introducing commit 5c755e9fd813 ("memory-hotplug: add sysfs removable attribute for hotplug memory remove") mentioned "A user-level agent must be able to identify which sections of memory are likely to be removable before attempting the potentially expensive operation." However, no actual performance comparison was included. Known users: - lsmem: Will group memory blocks based on the "removable" property. [1] - chmem: Indirect user. It has a RANGE mode where one can specify removable ranges identified via lsmem to be offlined. However, it also has a "SIZE" mode, which allows a sysadmin to skip the manual "identify removable blocks" step. [2] - powerpc-utils: Uses the "removable" attribute to skip some memory blocks right away when trying to find some to offline+remove. However, with ballooning enabled, it already skips this information completely (because it once resulted in many false negatives). Therefore, the implementation can deal with false positives properly already. [3] According to Nathan Fontenot, DLPAR on powerpc is nowadays no longer driven from userspace via the drmgr command (powerpc-utils). Nowadays it's managed in the kernel - including onlining/offlining of memory blocks - triggered by drmgr writing to /sys/kernel/dlpar. So the affected legacy userspace handling is only active on old kernels. Only very old versions of drmgr on a new kernel (unlikely) might execute slower - totally acceptable. With CONFIG_MEMORY_HOTREMOVE, always indicating "removable" should not break any user space tool. We implement a very bad heuristic now. Without CONFIG_MEMORY_HOTREMOVE we cannot offline anything, so report "not removable" as before. Original discussion can be found in [4] ("[PATCH RFC v1] mm: is_mem_section_removable() overhaul"). Other users of is_mem_section_removable() will be removed next, so that we can remove is_mem_section_removable() completely. [1] http://man7.org/linux/man-pages/man1/lsmem.1.html [2] http://man7.org/linux/man-pages/man8/chmem.8.html [3] https://github.com/ibm-power-utilities/powerpc-utils [4] https://lkml.kernel.org/r/20200117105759.27905-1-david@redhat.com Also, this patch probably fixes a crash reported by Steve. http://lkml.kernel.org/r/CAPcyv4jpdaNvJ67SkjyUJLBnBnXXQv686BiVW042g03FUmWLXw@mail.gmail.com Reported-by: "Scargall, Steve" Suggested-by: Michal Hocko Signed-off-by: David Hildenbrand Signed-off-by: Andrew Morton Reviewed-by: Nathan Fontenot Acked-by: Michal Hocko Cc: Dan Williams Cc: Greg Kroah-Hartman Cc: "Rafael J. Wysocki" Cc: Badari Pulavarty Cc: Robert Jennings Cc: Heiko Carstens Cc: Karel Zak Cc: Link: http://lkml.kernel.org/r/20200128093542.6908-1-david@redhat.com Signed-off-by: Linus Torvalds

driver code: clarify and fix platform device DMA mask allocation

2020-03-11T16:30:27Z

This does three inter-related things to clarify the usage of the platform device dma_mask field. In the process, fix the bug introduced by cdfee5623290 ("driver core: initialize a default DMA mask for platform device") that caused Artem Tashkinov's laptop to not boot with newer Fedora kernels. This does: - First off, rename the field to "platform_dma_mask" to make it greppable. We have way too many different random fields called "dma_mask" in various data structures, where some of them are actual masks, and some of them are just pointers to the mask. And the structures all have pointers to each other, or embed each other inside themselves, and "pdev" sometimes means "platform device" and sometimes it means "PCI device". So to make it clear in the code when you actually use this new field, give it a unique name (it really should be something even more unique like "platform_device_dma_mask", since it's per platform device, not per platform, but that gets old really fast, and this is unique enough in context). To further clarify when the field gets used, initialize it when we actually start using it with the default value. - Then, use this field instead of the random one-off allocation in platform_device_register_full() that is now unnecessary since we now already have a perfectly fine allocation for it in the platform device structure. - The above then allows us to fix the actual bug, where the error path of platform_device_register_full() would unconditionally free the platform device DMA allocation with 'kfree()'. That kfree() was dont regardless of whether the allocation had been done earlier with the (now removed) kmalloc, or whether setup_pdev_dma_masks() had already been used and the dma_mask pointer pointed to the mask that was part of the platform device. It seems most people never triggered the error path, or only triggered it from a call chain that set an explicit pdevinfo->dma_mask value (and thus caused the unnecessary allocation that was "cleaned up" in the error path) before calling platform_device_register_full(). Robin Murphy points out that in Artem's case the wdat_wdt driver failed in platform_device_add(), and that was the one that had called platform_device_register_full() with pdevinfo.dma_mask = 0, and would have caused that kfree() of pdev.dma_mask corrupting the heap. A later unrelated kmalloc() then oopsed due to the heap corruption. Fixes: cdfee5623290 ("driver core: initialize a default DMA mask for platform device") Reported-bisected-and-tested-by: Artem S. Tashkinov Reviewed-by: Robin Murphy Cc: Greg Kroah-Hartman Signed-off-by: Christoph Hellwig Signed-off-by: Linus Torvalds

Merge tag 'driver-core-5.6-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2020-03-08T15:39:40Z

Pull driver core and debugfs fixes from Greg KH: "Here are four small driver core / debugfs patches for 5.6-rc3: - debugfs api cleanup now that all debugfs_create_regset32() callers have been fixed up. This was waiting until after the -rc1 merge as these fixes came in through different trees - driver core sync state fixes based on reports of minor issues found in the feature All of these have been in linux-next with no reported issues" * tag 'driver-core-5.6-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: driver core: Skip unnecessary work when device doesn't have sync_state() driver core: Add dev_has_sync_state() driver core: Call sync_state() even if supplier has no consumers debugfs: remove return value of debugfs_create_regset32()

Revert "software node: Simplify software_node_release() function"

2020-03-04T21:31:44Z

This reverts commit 3df85a1ae51f6b256982fe9d17c2dc5bfb4cc402. The reverted commit says "It's possible to release the node ID immediately when fwnode_remove_software_node() is called, no need to wait for software_node_release() with that." However, releasing the node ID before waiting for software_node_release() to be called causes the node ID to be released before the kobject and the underlying sysfs entry; this means there is a period of time where a sysfs entry exists that is associated with an unallocated node ID. Once consequence of this is that there is a race condition where it is possible to call fwnode_create_software_node() with no parent node specified (NULL) and have it fail with -EEXIST because the node ID that was assigned is still associated with a stale sysfs entry that hasn't been cleaned up yet. Although it is difficult to reproduce this race condition under normal conditions, it can be deterministically reproduced with the following minconfig on UML: CONFIG_KUNIT_DRIVER_PE_TEST=y CONFIG_DEBUG_KERNEL=y CONFIG_DEBUG_OBJECTS=y CONFIG_DEBUG_OBJECTS_TIMERS=y CONFIG_DEBUG_KOBJECT_RELEASE=y CONFIG_KUNIT=y Running the tests with this configuration causes the following failure: kobject: 'node0' ((____ptrval____)): kobject_release, parent (____ptrval____) (delayed 400) ok 1 - pe_test_uints sysfs: cannot create duplicate filename '/kernel/software_nodes/node0' CPU: 0 PID: 28 Comm: kunit_try_catch Not tainted 5.6.0-rc3-next-20200227 #14 kobject_add_internal failed for node0 with -EEXIST, don't try to register things with the same name in the same directory. kobject: 'node0' ((____ptrval____)): kobject_release, parent (____ptrval____) (delayed 100) # pe_test_uint_arrays: ASSERTION FAILED at drivers/base/test/property-entry-test.c:123 Expected node is not error, but is: -17 not ok 2 - pe_test_uint_arrays Reported-by: Heidi Fahim Signed-off-by: Brendan Higgins Reviewed-by: Heikki Krogerus Cc: 5.3+ # 5.3+ Signed-off-by: Rafael J. Wysocki

driver core: Skip unnecessary work when device doesn't have sync_state()

2020-03-04T12:46:03Z

A bunch of busy work is done for devices that don't have sync_state() support. Stop doing the busy work. Signed-off-by: Saravana Kannan Link: https://lore.kernel.org/r/20200221080510.197337-4-saravanak@google.com Signed-off-by: Greg Kroah-Hartman

driver core: Call sync_state() even if supplier has no consumers

2020-03-04T12:46:03Z

The initial patch that added sync_state() support didn't handle the case where a supplier has no consumers. This was because when a device is successfully bound with a driver, only its suppliers were checked to see if they are eligible to get a sync_state(). This is not sufficient for devices that have no consumers but still need to do device state clean up. So fix this. Fixes: fc5a251d0fd7ca90 (driver core: Add sync_state driver/bus callback) Signed-off-by: Saravana Kannan Cc: stable Link: https://lore.kernel.org/r/20200221080510.197337-2-saravanak@google.com Signed-off-by: Greg Kroah-Hartman

Merge tag 'armsoc-drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc

2020-02-08T22:04:19Z

Pull ARM SoC-related driver updates from Olof Johansson: "Various driver updates for platforms: - Nvidia: Fuse support for Tegra194, continued memory controller pieces for Tegra30 - NXP/FSL: Refactorings of QuickEngine drivers to support ARM/ARM64/PPC - NXP/FSL: i.MX8MP SoC driver pieces - TI Keystone: ring accelerator driver - Qualcomm: SCM driver cleanup/refactoring + support for new SoCs. - Xilinx ZynqMP: feature checking interface for firmware. Mailbox communication for power management - Overall support patch set for cpuidle on more complex hierarchies (PSCI-based) and misc cleanups, refactorings of Marvell, TI, other platforms" * tag 'armsoc-drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/soc/soc: (166 commits) drivers: soc: xilinx: Use mailbox IPI callback dt-bindings: power: reset: xilinx: Add bindings for ipi mailbox drivers: soc: ti: knav_qmss_queue: Pass lockdep expression to RCU lists MAINTAINERS: Add brcmstb PCIe controller entry soc/tegra: fuse: Unmap registers once they are not needed anymore soc/tegra: fuse: Correct straps' address for older Tegra124 device trees soc/tegra: fuse: Warn if straps are not ready soc/tegra: fuse: Cache values of straps and Chip ID registers memory: tegra30-emc: Correct error message for timed out auto calibration memory: tegra30-emc: Firm up hardware programming sequence memory: tegra30-emc: Firm up suspend/resume sequence soc/tegra: regulators: Do nothing if voltage is unchanged memory: tegra: Correct reset value of xusb_hostr soc/tegra: fuse: Add APB DMA dependency for Tegra20 bus: tegra-aconnect: Remove PM_CLK dependency dt-bindings: mediatek: add MT6765 power dt-bindings soc: mediatek: cmdq: delete not used define memory: tegra: Add support for the Tegra194 memory controller memory: tegra: Only include support for enabled SoCs memory: tegra: Support DVFS on Tegra186 and later ...

Merge branch 'merge.nfs-fs_parse.1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2020-02-08T21:26:41Z

Pull vfs file system parameter updates from Al Viro: "Saner fs_parser.c guts and data structures. The system-wide registry of syntax types (string/enum/int32/oct32/.../etc.) is gone and so is the horror switch() in fs_parse() that would have to grow another case every time something got added to that system-wide registry. New syntax types can be added by filesystems easily now, and their namespace is that of functions - not of system-wide enum members. IOW, they can be shared or kept private and if some turn out to be widely useful, we can make them common library helpers, etc., without having to do anything whatsoever to fs_parse() itself. And we already get that kind of requests - the thing that finally pushed me into doing that was "oh, and let's add one for timeouts - things like 15s or 2h". If some filesystem really wants that, let them do it. Without somebody having to play gatekeeper for the variants blessed by direct support in fs_parse(), TYVM. Quite a bit of boilerplate is gone. And IMO the data structures make a lot more sense now. -200LoC, while we are at it" * 'merge.nfs-fs_parse.1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (25 commits) tmpfs: switch to use of invalfc() cgroup1: switch to use of errorfc() et.al. procfs: switch to use of invalfc() hugetlbfs: switch to use of invalfc() cramfs: switch to use of errofc() et.al. gfs2: switch to use of errorfc() et.al. fuse: switch to use errorfc() et.al. ceph: use errorfc() and friends instead of spelling the prefix out prefix-handling analogues of errorf() and friends turn fs_param_is_... into functions fs_parse: handle optional arguments sanely fs_parse: fold fs_parameter_desc/fs_parameter_spec fs_parser: remove fs_parameter_description name field add prefix to fs_context->log ceph_parse_param(), ceph_parse_mon_ips(): switch to passing fc_log new primitive: __fs_parse() switch rbd and libceph to p_log-based primitives struct p_log, variants of warnf() et.al. taking that one instead teach logfc() to handle prefices, give it saner calling conventions get rid of cg_invalf() ...

fs_parse: fold fs_parameter_desc/fs_parameter_spec

2020-02-07T19:48:37Z

The former contains nothing but a pointer to an array of the latter... Signed-off-by: Al Viro

mm/memory_hotplug: drop valid_start/valid_end from test_pages_in_a_zone()

2020-02-04T03:05:23Z

The callers are only interested in the actual zone, they don't care about boundaries. Return the zone instead to simplify. Link: http://lkml.kernel.org/r/20200110183308.11849-1-david@redhat.com Signed-off-by: David Hildenbrand Cc: Greg Kroah-Hartman Cc: "Rafael J. Wysocki" Cc: Michal Hocko Cc: Oscar Salvador Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds