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| author | Herbert Xu <herbert@gondor.apana.org.au> | 2025-09-09 12:50:56 +0300 |
|---|---|---|
| committer | Herbert Xu <herbert@gondor.apana.org.au> | 2025-09-20 15:21:03 +0300 |
| commit | bee8a520eb84950193d0566ea2c2e46406a4b6ce (patch) | |
| tree | 05d57af231a42ea997165138038b75362986862d /include/linux/rcupdate.h | |
| parent | f75f66683ded09f7135aef2e763c245a07c8271a (diff) | |
| download | linux-bee8a520eb84950193d0566ea2c2e46406a4b6ce.tar.xz | |
rhashtable: Use rcu_dereference_all and rcu_dereference_all_check
Add rcu_dereference_all and rcu_dereference_all_check so that
library code such as rhashtable can be used with any RCU variant.
As it stands rcu_dereference is used within rashtable, which
creates false-positive warnings if the user calls it from another
RCU context, such as preempt_disable().
Use the rcu_dereference_all and rcu_dereference_all_check calls
in rhashtable to suppress these warnings.
Also replace the rcu_dereference_raw calls in the list iterators
with rcu_dereference_all to uncover buggy calls.
Reported-by: Menglong Dong <dongml2@chinatelecom.cn>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'include/linux/rcupdate.h')
| -rw-r--r-- | include/linux/rcupdate.h | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 120536f4c6eb..448eb1f0cb48 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -713,6 +713,24 @@ do { \ (c) || rcu_read_lock_sched_held(), \ __rcu) +/** + * rcu_dereference_all_check() - rcu_dereference_all with debug checking + * @p: The pointer to read, prior to dereferencing + * @c: The conditions under which the dereference will take place + * + * This is similar to rcu_dereference_check(), but allows protection + * by all forms of vanilla RCU readers, including preemption disabled, + * bh-disabled, and interrupt-disabled regions of code. Note that "vanilla + * RCU" excludes SRCU and the various Tasks RCU flavors. Please note + * that this macro should not be backported to any Linux-kernel version + * preceding v5.0 due to changes in synchronize_rcu() semantics prior + * to that version. + */ +#define rcu_dereference_all_check(p, c) \ + __rcu_dereference_check((p), __UNIQUE_ID(rcu), \ + (c) || rcu_read_lock_any_held(), \ + __rcu) + /* * The tracing infrastructure traces RCU (we want that), but unfortunately * some of the RCU checks causes tracing to lock up the system. @@ -768,6 +786,14 @@ do { \ #define rcu_dereference_sched(p) rcu_dereference_sched_check(p, 0) /** + * rcu_dereference_all() - fetch RCU-all-protected pointer for dereferencing + * @p: The pointer to read, prior to dereferencing + * + * Makes rcu_dereference_check() do the dirty work. + */ +#define rcu_dereference_all(p) rcu_dereference_all_check(p, 0) + +/** * rcu_pointer_handoff() - Hand off a pointer from RCU to other mechanism * @p: The pointer to hand off * |