From c41108049d143304faf06852c7181262b7b0d242 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Tue, 12 Oct 2021 11:33:01 +0200 Subject: [PATCH] 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 Link: https://lore.kernel.org/r/20211012093301.GA27795@lst.de Tested-by: Yi Zhang Signed-off-by: Jens Axboe --- block/kyber-iosched.c | 10 ++++++---- include/trace/events/kyber.h | 19 +++++++++---------- 2 files changed, 15 insertions(+), 14 deletions(-) diff --git a/block/kyber-iosched.c b/block/kyber-iosched.c index 15a8be57203d..a0ffbabfac2c 100644 --- a/block/kyber-iosched.c +++ b/block/kyber-iosched.c @@ -151,6 +151,7 @@ struct kyber_ctx_queue { 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 @@ static int calculate_percentile(struct kyber_queue_data *kqd, } 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 @@ static void kyber_resize_domain(struct kyber_queue_data *kqd, 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 @@ static struct kyber_queue_data *kyber_queue_data_alloc(struct request_queue *q) 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 @@ kyber_dispatch_cur_domain(struct kyber_queue_data *kqd, 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 @@ kyber_dispatch_cur_domain(struct kyber_queue_data *kqd, 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 491098a0d8ed..bf7533f171ff 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 @@ TRACE_EVENT(kyber_latency, ), 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_latency, 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 @@ TRACE_EVENT(kyber_adjust, ), 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_adjust, 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 @@ TRACE_EVENT(kyber_throttled, ), TP_fast_assign( - __entry->dev = disk_devt(q->disk); + __entry->dev = dev; strlcpy(__entry->domain, domain, sizeof(__entry->domain)); ),