diff options
| -rw-r--r-- | drivers/gpu/drm/v3d/v3d_sched.c | 46 |
1 files changed, 41 insertions, 5 deletions
diff --git a/drivers/gpu/drm/v3d/v3d_sched.c b/drivers/gpu/drm/v3d/v3d_sched.c index f58c38d7de29..99ac4995b5a1 100644 --- a/drivers/gpu/drm/v3d/v3d_sched.c +++ b/drivers/gpu/drm/v3d/v3d_sched.c @@ -135,8 +135,31 @@ v3d_job_start_stats(struct v3d_job *job, enum v3d_queue queue) struct v3d_stats *global_stats = &v3d->queue[queue].stats; struct v3d_stats *local_stats = &file->stats[queue]; u64 now = local_clock(); - - preempt_disable(); + unsigned long flags; + + /* + * We only need to disable local interrupts to appease lockdep who + * otherwise would think v3d_job_start_stats vs v3d_stats_update has an + * unsafe in-irq vs no-irq-off usage problem. This is a false positive + * because all the locks are per queue and stats type, and all jobs are + * completely one at a time serialised. More specifically: + * + * 1. Locks for GPU queues are updated from interrupt handlers under a + * spin lock and started here with preemption disabled. + * + * 2. Locks for CPU queues are updated from the worker with preemption + * disabled and equally started here with preemption disabled. + * + * Therefore both are consistent. + * + * 3. Because next job can only be queued after the previous one has + * been signaled, and locks are per queue, there is also no scope for + * the start part to race with the update part. + */ + if (IS_ENABLED(CONFIG_LOCKDEP)) + local_irq_save(flags); + else + preempt_disable(); write_seqcount_begin(&local_stats->lock); local_stats->start_ns = now; @@ -146,7 +169,10 @@ v3d_job_start_stats(struct v3d_job *job, enum v3d_queue queue) global_stats->start_ns = now; write_seqcount_end(&global_stats->lock); - preempt_enable(); + if (IS_ENABLED(CONFIG_LOCKDEP)) + local_irq_restore(flags); + else + preempt_enable(); } static void @@ -167,11 +193,21 @@ v3d_job_update_stats(struct v3d_job *job, enum v3d_queue queue) struct v3d_stats *global_stats = &v3d->queue[queue].stats; struct v3d_stats *local_stats = &file->stats[queue]; u64 now = local_clock(); + unsigned long flags; + + /* See comment in v3d_job_start_stats() */ + if (IS_ENABLED(CONFIG_LOCKDEP)) + local_irq_save(flags); + else + preempt_disable(); - preempt_disable(); v3d_stats_update(local_stats, now); v3d_stats_update(global_stats, now); - preempt_enable(); + + if (IS_ENABLED(CONFIG_LOCKDEP)) + local_irq_restore(flags); + else + preempt_enable(); } static struct dma_fence *v3d_bin_job_run(struct drm_sched_job *sched_job) |