kernel/linux.git/lib/rhashtable.c, branch v6.12.80

rhashtable: Fix rhashtable_try_insert test

2025-02-08T08:57:35+00:00

[ Upstream commit 9d4f8e54cef2c42e23ef258833dbd06a1eaff89b ] The test on whether rhashtable_insert_one did an insertion relies on the value returned by rhashtable_lookup_one. Unfortunately that value is overwritten after rhashtable_insert_one returns. Fix this by moving the test before data gets overwritten. Simplify the test as only data == NULL matters. Finally move atomic_inc back within the lock as otherwise it may be reordered with the atomic_dec on the removal side, potentially leading to an underflow. Reported-by: Michael Kelley Fixes: e1d3422c95f0 ("rhashtable: Fix potential deadlock by moving schedule_work outside lock") Signed-off-by: Herbert Xu Tested-by: Michael Kelley Reviewed-by: Breno Leitao Tested-by: Mikhail Zaslonko Signed-off-by: Herbert Xu Signed-off-by: Sasha Levin

rhashtable: Fix potential deadlock by moving schedule_work outside lock

2025-02-08T08:57:29+00:00

[ Upstream commit e1d3422c95f003eba241c176adfe593c33e8a8f6 ] Move the hash table growth check and work scheduling outside the rht lock to prevent a possible circular locking dependency. The original implementation could trigger a lockdep warning due to a potential deadlock scenario involving nested locks between rhashtable bucket, rq lock, and dsq lock. By relocating the growth check and work scheduling after releasing the rth lock, we break this potential deadlock chain. This change expands the flexibility of rhashtable by removing restrictive locking that previously limited its use in scheduler and workqueue contexts. Import to say that this calls rht_grow_above_75(), which reads from struct rhashtable without holding the lock, if this is a problem, we can move the check to the lock, and schedule the workqueue after the lock. Fixes: f0e1a0643a59 ("sched_ext: Implement BPF extensible scheduler class") Suggested-by: Tejun Heo Signed-off-by: Breno Leitao Modified so that atomic_inc is also moved outside of the bucket lock along with the growth above 75% check. Signed-off-by: Herbert Xu Signed-off-by: Sasha Levin

lib/rhashtable: cleanup fallback check in bucket_table_alloc()

2024-09-02T03:43:32+00:00

Upon allocation failure, the current check with the nofail bits is unnecessary, and further stands in the way of discouraging direct use of __GFP_NOFAIL. Remove this and replace with the proper way of determining if doing a non-blocking allocation for the nested table case. Link: https://lkml.kernel.org/r/20240806153927.184515-1-dave@stgolabs.net Signed-off-by: Davidlohr Bueso Suggested-by: Michal Hocko Cc: Davidlohr Bueso Cc: Herbert Xu Signed-off-by: Andrew Morton

rhashtable: plumb through alloc tag

2024-04-26T03:55:57+00:00

This gives better memory allocation profiling results; rhashtable allocations will be accounted to the code that initialized the rhashtable. [surenb@google.com: undo _noprof additions in the documentation] Link: https://lkml.kernel.org/r/20240326231453.1206227-1-surenb@google.com Link: https://lkml.kernel.org/r/20240321163705.3067592-32-surenb@google.com Signed-off-by: Kent Overstreet Signed-off-by: Suren Baghdasaryan Tested-by: Kees Cook Cc: Alexander Viro Cc: Alex Gaynor Cc: Alice Ryhl Cc: Andreas Hindborg Cc: Benno Lossin Cc: "Björn Roy Baron" Cc: Boqun Feng Cc: Christoph Lameter Cc: Dennis Zhou Cc: Gary Guo Cc: Miguel Ojeda Cc: Pasha Tatashin Cc: Peter Zijlstra Cc: Tejun Heo Cc: Vlastimil Babka Cc: Wedson Almeida Filho Signed-off-by: Andrew Morton

rhashtable: Allow rhashtable to be used from irq-safe contexts

2022-12-09T10:42:56+00:00

rhashtable currently only does bh-safe synchronization making it impossible to use from irq-safe contexts. Switch it to use irq-safe synchronization to remove the restriction. v2: Update the lock functions to return the ulong flags value and unlock functions to take the value directly instead of passing around the pointer. Suggested by Linus. Signed-off-by: Tejun Heo Reviewed-by: David Vernet Acked-by: Josh Don Acked-by: Hao Luo Acked-by: Barret Rhoden Cc: Linus Torvalds Signed-off-by: David S. Miller

lib: fix spelling mistakes

2021-07-08T18:48:20+00:00

Fix some spelling mistakes in comments: permanentely ==> permanently wont ==> won't remaning ==> remaining succed ==> succeed shouldnt ==> shouldn't alpha-numeric ==> alphanumeric storeing ==> storing funtion ==> function documenation ==> documentation Determin ==> Determine intepreted ==> interpreted ammount ==> amount obious ==> obvious interupts ==> interrupts occured ==> occurred asssociated ==> associated taking into acount ==> taking into account squence ==> sequence stil ==> still contiguos ==> contiguous matchs ==> matches Link: https://lkml.kernel.org/r/20210607072555.12416-1-thunder.leizhen@huawei.com Signed-off-by: Zhen Lei Reviewed-by: Jacob Keller Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

rhashtable: Restore RCU marking on rhash_lock_head

2020-07-29T00:09:49+00:00

This patch restores the RCU marking on bucket_table->buckets as it really does need RCU protection. Its removal had led to a fatal bug. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller

rhashtable: Drop raw RCU deref in nested_table_free

2020-06-06T22:51:17+00:00

This patch replaces some unnecessary uses of rcu_dereference_raw in the rhashtable code with rcu_dereference_protected. The top-level nested table entry is only marked as RCU because it shares the same type as the tree entries underneath it. So it doesn't need any RCU protection. We also don't need RCU protection when we're freeing a nested RCU table because by this stage we've long passed a memory barrier when anyone could change the nested table. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

2019-06-19T15:09:55+00:00

Based on 2 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 as published by the free software foundation # extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 4122 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Enrico Weigelt Reviewed-by: Kate Stewart Reviewed-by: Allison Randal Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de Signed-off-by: Greg Kroah-Hartman

rhashtable: Fix cmpxchg RCU warnings

2019-05-16T16:45:20+00:00

As cmpxchg is a non-RCU mechanism it will cause sparse warnings when we use it for RCU. This patch adds explicit casts to silence those warnings. This should probably be moved to RCU itself in future. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller