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

workqueue: clean up WORK_* constant types, clarify masking

2023-06-23T19:08:14Z

Dave Airlie reports that gcc-13.1.1 has started complaining about some of the workqueue code in 32-bit arm builds: kernel/workqueue.c: In function ‘get_work_pwq’: kernel/workqueue.c:713:24: error: cast to pointer from integer of different size [-Werror=int-to-pointer-cast] 713 | return (void *)(data & WORK_STRUCT_WQ_DATA_MASK); | ^ [ ... a couple of other cases ... ] and while it's not immediately clear exactly why gcc started complaining about it now, I suspect it's some C23-induced enum type handlign fixup in gcc-13 is the cause. Whatever the reason for starting to complain, the code and data types are indeed disgusting enough that the complaint is warranted. The wq code ends up creating various "helper constants" (like that WORK_STRUCT_WQ_DATA_MASK) using an enum type, which is all kinds of confused. The mask needs to be 'unsigned long', not some unspecified enum type. To make matters worse, the actual "mask and cast to a pointer" is repeated a couple of times, and the cast isn't even always done to the right pointer, but - as the error case above - to a 'void *' with then the compiler finishing the job. That's now how we roll in the kernel. So create the masks using the proper types rather than some ambiguous enumeration, and use a nice helper that actually does the type conversion in one well-defined place. Incidentally, this magically makes clang generate better code. That, admittedly, is really just a sign of clang having been seriously confused before, and cleaning up the typing unconfuses the compiler too. Reported-by: Dave Airlie Link: https://lore.kernel.org/lkml/CAPM=9twNnV4zMCvrPkw3H-ajZOH-01JVh_kDrxdPYQErz8ZTdA@mail.gmail.com/ Cc: Arnd Bergmann Cc: Tejun Heo Cc: Nick Desaulniers Cc: Nathan Chancellor Signed-off-by: Linus Torvalds

workqueue: Introduce show_freezable_workqueues

2023-03-24T01:55:38Z

Currently show_all_workqueue is called if freeze fails at the time of freeze the workqueues, which shows the status of all workqueues and of all worker pools. In this cases we may only need to dump state of only workqueues that are freezable and busy. This patch defines show_freezable_workqueues, which uses show_one_workqueue, a granular function that shows the state of individual workqueues, so that dump only the state of freezable workqueues at that time. tj: Minor message adjustment. Signed-off-by: Jungseung Lee Signed-off-by: Tejun Heo

workqueue: Add a new flag to spot the potential UAF error

2023-01-04T22:25:29Z

Currently if the user queues a new work item unintentionally into a wq after the destroy_workqueue(wq), the work still can be queued and scheduled without any noticeable kernel message before the end of a RCU grace period. As a debug-aid facility, this commit adds a new flag __WQ_DESTROYING to spot that issue by triggering a kernel WARN message. Signed-off-by: Richard Clark Reviewed-by: Lai Jiangshan Signed-off-by: Tejun Heo

Merge tag 'amd-drm-next-5.20-2022-07-05' of https://gitlab.freedesktop.org/agd5f/linux into drm-next

2022-07-12T01:07:32Z

amd-drm-next-5.20-2022-07-05: amdgpu: - Various spelling and grammer fixes - Various eDP fixes - Various DMCUB fixes - VCN fixes - GMC 11 fixes - RAS fixes - TMZ support for GC 10.3.7 - GPUVM TLB flush fixes - SMU 13.0.x updates - DCN 3.2 Support - DCN 3.2.1 Support - MES updates - GFX11 modifiers support - USB-C fixes - MMHUB 3.0.1 support - SDMA 6.0 doorbell fixes - Initial devcoredump support - Enable high priority gfx queue on asics which support it - Enable GPU reset for SMU 13.0.4 - OLED display fixes - MPO fixes - DC frame size fixes - ASPM support for PCIE 7.4/7.6 - GPU reset support for SMU 13.0.0 - GFX11 updates - VCN JPEG fix - BACO support for SMU 13.0.7 - VCN instance handling fix - GFX8 GPUVM TLB flush fix - GPU reset rework - VCN 4.0.2 support - GTT size fixes - DP link training fixes - LSDMA 6.0.1 support - Various backlight fixes - Color encoding fixes - Backlight config cleanup - VCN 4.x unified queue cleanup amdkfd: - MMU notifier fixes - Updates for GC 10.3.6 and 10.3.7 - P2P DMA support using dma-buf - Add available memory IOCTL - SDMA 6.0.1 fix - MES fixes - HMM profiler support radeon: - License fix - Backlight config cleanup UAPI: - Add available memory IOCTL to amdkfd Proposed userspace: https://www.mail-archive.com/amd-gfx@lists.freedesktop.org/msg75743.html - HMM profiler support for amdkfd Proposed userspace: https://lists.freedesktop.org/archives/amd-gfx/2022-June/080805.html Signed-off-by: Dave Airlie From: Alex Deucher Link: https://patchwork.freedesktop.org/patch/msgid/20220705212633.6037-1-alexander.deucher@amd.com

workqueue: Switch to new kerneldoc syntax for named variable macro argument

2022-06-12T00:16:42Z

The syntax without dots is available since commit 43756e347f21 ("scripts/kernel-doc: Add support for named variable macro arguments"). The same HTML output is produced with and without this patch. Signed-off-by: Jonathan Neuschäfer Acked-by: Tejun Heo Signed-off-by: Tejun Heo

Revert "workqueue: remove unused cancel_work()"

2022-06-10T19:24:38Z

This reverts commit 6417250d3f894e66a68ba1cd93676143f2376a6f. amdpgu need this function in order to prematurly stop pending reset works when another reset work already in progress. Acked-by: Tejun Heo Signed-off-by: Andrey Grodzovsky Reviewed-by: Lai Jiangshan Reviewed-by: Christian König Signed-off-by: Alex Deucher

workqueue: Wrap flush_workqueue() using a macro

2022-06-07T17:07:14Z

Since flush operation synchronously waits for completion, flushing system-wide WQs (e.g. system_wq) might introduce possibility of deadlock due to unexpected locking dependency. Tejun Heo commented at [1] that it makes no sense at all to call flush_workqueue() on the shared WQs as the caller has no idea what it's gonna end up waiting for. Although there is flush_scheduled_work() which flushes system_wq WQ with "Think twice before calling this function! It's very easy to get into trouble if you don't take great care." warning message, syzbot found a circular locking dependency caused by flushing system_wq WQ [2]. Therefore, let's change the direction to that developers had better use their local WQs if flush_scheduled_work()/flush_workqueue(system_*_wq) is inevitable. Steps for converting system-wide WQs into local WQs are explained at [3], and a conversion to stop flushing system-wide WQs is in progress. Now we want some mechanism for preventing developers who are not aware of this conversion from again start flushing system-wide WQs. Since I found that WARN_ON() is complete but awkward approach for teaching developers about this problem, let's use __compiletime_warning() for incomplete but handy approach. For completeness, we will also insert WARN_ON() into __flush_workqueue() after all in-tree users stopped calling flush_scheduled_work(). Link: https://lore.kernel.org/all/YgnQGZWT%2Fn3VAITX@slm.duckdns.org/ [1] Link: https://syzkaller.appspot.com/bug?extid=bde0f89deacca7c765b8 [2] Link: https://lkml.kernel.org/r/49925af7-78a8-a3dd-bce6-cfc02e1a9236@I-love.SAKURA.ne.jp [3] Signed-off-by: Tetsuo Handa Signed-off-by: Tejun Heo

workqueue: Introduce show_one_worker_pool and show_one_workqueue.

2021-10-20T16:19:03Z

Currently show_workqueue_state shows the state of all workqueues and of all worker pools. In certain cases we may need to dump state of only a specific workqueue or worker pool. For example in destroy_workqueue we only need to show state of the workqueue which is getting destroyed. So rename show_workqueue_state to show_all_workqueues(to signify it dumps state of all busy workqueues) and divide it into more granular functions (show_one_workqueue and show_one_worker_pool), that would show states of individual workqueues and worker pools and can be used in cases such as the one mentioned above. Also, as mentioned earlier, make destroy_workqueue dump data pertaining to only the workqueue that is being destroyed and make user(s) of earlier interface(show_workqueue_state), use new interface (show_all_workqueues). Signed-off-by: Imran Khan Signed-off-by: Tejun Heo

workqueue: annotate alloc_workqueue() as printf

2021-09-13T17:53:27Z

This also enables checking of allows alloc_ordered_workqueue(). Signed-off-by: Rolf Eike Beer Signed-off-by: Tejun Heo

workqueue: Remove unused WORK_NO_COLOR

2021-08-17T17:49:10Z

WORK_NO_COLOR has no user now, just remove it. Signed-off-by: Lai Jiangshan Signed-off-by: Tejun Heo