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author | Paul E. McKenney <paulmck@kernel.org> | 2024-02-15 09:04:30 -0800 |
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committer | Uladzislau Rezki (Sony) <urezki@gmail.com> | 2024-04-15 11:29:48 +0200 |
commit | 65b4a59557f6fb5d4355093ad5a2c1bd5598ee41 (patch) | |
tree | 31a5e70e4a09cfb69d4752364a9ab58297ba4134 /include/linux/srcutiny.h | |
parent | c1ec7c158090ab968ab9022a9f67e7d88d66ee61 (diff) | |
download | lwn-65b4a59557f6fb5d4355093ad5a2c1bd5598ee41.tar.gz lwn-65b4a59557f6fb5d4355093ad5a2c1bd5598ee41.zip |
srcu: Make Tiny SRCU explicitly disable preemption
Because Tiny SRCU is used only in kernels built with either
CONFIG_PREEMPT_NONE=y or CONFIG_PREEMPT_VOLUNTARY=y, there has not
been any need for TINY SRCU to explicitly disable preemption. However,
the prospect of lazy preemption changes that, and the lazy-preemption
patches do result in rcutorture runs finding both too-short grace periods
and grace-period hangs for Tiny SRCU.
This commit therefore adds the needed preempt_disable() and
preempt_enable() calls to Tiny SRCU.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Ankur Arora <ankur.a.arora@oracle.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Diffstat (limited to 'include/linux/srcutiny.h')
-rw-r--r-- | include/linux/srcutiny.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/srcutiny.h b/include/linux/srcutiny.h index 447133171d95..4d96bbdb45f0 100644 --- a/include/linux/srcutiny.h +++ b/include/linux/srcutiny.h @@ -64,8 +64,10 @@ static inline int __srcu_read_lock(struct srcu_struct *ssp) { int idx; + preempt_disable(); // Needed for PREEMPT_AUTO idx = ((READ_ONCE(ssp->srcu_idx) + 1) & 0x2) >> 1; WRITE_ONCE(ssp->srcu_lock_nesting[idx], READ_ONCE(ssp->srcu_lock_nesting[idx]) + 1); + preempt_enable(); return idx; } |