kyber: avoid q->disk dereferences in trace points
q->disk becomes invalid after the gendisk is removed. Work around this
by caching the dev_t for the tracepoints. The real fix would be to
properly tear down the I/O schedulers with the gendisk, but that is
a much more invasive change.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20211012093301.GA27795@lst.de
Tested-by: Yi Zhang <yi.zhang@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/kyber-iosched.c b/block/kyber-iosched.c
index 15a8be57..a0ffbab 100644
--- a/block/kyber-iosched.c
+++ b/block/kyber-iosched.c
@@ -151,6 +151,7 @@
struct kyber_queue_data {
struct request_queue *q;
+ dev_t dev;
/*
* Each scheduling domain has a limited number of in-flight requests
@@ -257,7 +258,7 @@
}
memset(buckets, 0, sizeof(kqd->latency_buckets[sched_domain][type]));
- trace_kyber_latency(kqd->q, kyber_domain_names[sched_domain],
+ trace_kyber_latency(kqd->dev, kyber_domain_names[sched_domain],
kyber_latency_type_names[type], percentile,
bucket + 1, 1 << KYBER_LATENCY_SHIFT, samples);
@@ -270,7 +271,7 @@
depth = clamp(depth, 1U, kyber_depth[sched_domain]);
if (depth != kqd->domain_tokens[sched_domain].sb.depth) {
sbitmap_queue_resize(&kqd->domain_tokens[sched_domain], depth);
- trace_kyber_adjust(kqd->q, kyber_domain_names[sched_domain],
+ trace_kyber_adjust(kqd->dev, kyber_domain_names[sched_domain],
depth);
}
}
@@ -366,6 +367,7 @@
goto err;
kqd->q = q;
+ kqd->dev = disk_devt(q->disk);
kqd->cpu_latency = alloc_percpu_gfp(struct kyber_cpu_latency,
GFP_KERNEL | __GFP_ZERO);
@@ -774,7 +776,7 @@
list_del_init(&rq->queuelist);
return rq;
} else {
- trace_kyber_throttled(kqd->q,
+ trace_kyber_throttled(kqd->dev,
kyber_domain_names[khd->cur_domain]);
}
} else if (sbitmap_any_bit_set(&khd->kcq_map[khd->cur_domain])) {
@@ -787,7 +789,7 @@
list_del_init(&rq->queuelist);
return rq;
} else {
- trace_kyber_throttled(kqd->q,
+ trace_kyber_throttled(kqd->dev,
kyber_domain_names[khd->cur_domain]);
}
}
diff --git a/include/trace/events/kyber.h b/include/trace/events/kyber.h
index 491098a..bf7533f 100644
--- a/include/trace/events/kyber.h
+++ b/include/trace/events/kyber.h
@@ -13,11 +13,11 @@
TRACE_EVENT(kyber_latency,
- TP_PROTO(struct request_queue *q, const char *domain, const char *type,
+ TP_PROTO(dev_t dev, const char *domain, const char *type,
unsigned int percentile, unsigned int numerator,
unsigned int denominator, unsigned int samples),
- TP_ARGS(q, domain, type, percentile, numerator, denominator, samples),
+ TP_ARGS(dev, domain, type, percentile, numerator, denominator, samples),
TP_STRUCT__entry(
__field( dev_t, dev )
@@ -30,7 +30,7 @@
),
TP_fast_assign(
- __entry->dev = disk_devt(q->disk);
+ __entry->dev = dev;
strlcpy(__entry->domain, domain, sizeof(__entry->domain));
strlcpy(__entry->type, type, sizeof(__entry->type));
__entry->percentile = percentile;
@@ -47,10 +47,9 @@
TRACE_EVENT(kyber_adjust,
- TP_PROTO(struct request_queue *q, const char *domain,
- unsigned int depth),
+ TP_PROTO(dev_t dev, const char *domain, unsigned int depth),
- TP_ARGS(q, domain, depth),
+ TP_ARGS(dev, domain, depth),
TP_STRUCT__entry(
__field( dev_t, dev )
@@ -59,7 +58,7 @@
),
TP_fast_assign(
- __entry->dev = disk_devt(q->disk);
+ __entry->dev = dev;
strlcpy(__entry->domain, domain, sizeof(__entry->domain));
__entry->depth = depth;
),
@@ -71,9 +70,9 @@
TRACE_EVENT(kyber_throttled,
- TP_PROTO(struct request_queue *q, const char *domain),
+ TP_PROTO(dev_t dev, const char *domain),
- TP_ARGS(q, domain),
+ TP_ARGS(dev, domain),
TP_STRUCT__entry(
__field( dev_t, dev )
@@ -81,7 +80,7 @@
),
TP_fast_assign(
- __entry->dev = disk_devt(q->disk);
+ __entry->dev = dev;
strlcpy(__entry->domain, domain, sizeof(__entry->domain));
),
