diff options
| author | Christian Loehle <christian.loehle@arm.com> | 2025-09-03 22:23:09 +0100 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2025-09-03 11:50:36 -1000 |
| commit | e0ca169638be12a0a861e3439e6117c58972cd08 (patch) | |
| tree | d358a6c5b3bdb506cfb3e4ad2834f7eba9a2559f /kernel/sched | |
| parent | a5bd6ba30b3364354269b81ac55c2edca9a96d6d (diff) | |
sched_ext: Introduce scx_bpf_locked_rq()
Most fields in scx_bpf_cpu_rq() assume that its rq_lock is held.
Furthermore they become meaningless without rq lock, too.
Make a safer version of scx_bpf_cpu_rq() that only returns a rq
if we hold rq lock of that rq.
Also mark the new scx_bpf_locked_rq() as returning NULL as
scx_bpf_cpu_rq() should've been too.
Signed-off-by: Christian Loehle <christian.loehle@arm.com>
Acked-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/sched')
| -rw-r--r-- | kernel/sched/ext.c | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/kernel/sched/ext.c b/kernel/sched/ext.c index 520f20ffb7bf..a319ea5bb25a 100644 --- a/kernel/sched/ext.c +++ b/kernel/sched/ext.c @@ -6358,6 +6358,28 @@ __bpf_kfunc struct rq *scx_bpf_cpu_rq(s32 cpu) } /** + * scx_bpf_locked_rq - Return the rq currently locked by SCX + * + * Returns the rq if a rq lock is currently held by SCX. + * Otherwise emits an error and returns NULL. + */ +__bpf_kfunc struct rq *scx_bpf_locked_rq(void) +{ + struct rq *rq; + + preempt_disable(); + rq = scx_locked_rq(); + if (!rq) { + preempt_enable(); + scx_kf_error("accessing rq without holding rq lock"); + return NULL; + } + preempt_enable(); + + return rq; +} + +/** * scx_bpf_task_cgroup - Return the sched cgroup of a task * @p: task of interest * @@ -6521,6 +6543,7 @@ BTF_ID_FLAGS(func, scx_bpf_put_cpumask, KF_RELEASE) BTF_ID_FLAGS(func, scx_bpf_task_running, KF_RCU) BTF_ID_FLAGS(func, scx_bpf_task_cpu, KF_RCU) BTF_ID_FLAGS(func, scx_bpf_cpu_rq) +BTF_ID_FLAGS(func, scx_bpf_locked_rq, KF_RET_NULL) #ifdef CONFIG_CGROUP_SCHED BTF_ID_FLAGS(func, scx_bpf_task_cgroup, KF_RCU | KF_ACQUIRE) #endif |