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authorLinus Torvalds <torvalds@linux-foundation.org>2022-06-03 19:14:48 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2022-06-03 19:14:48 +0200
commit34845d92bca527b5c2cf8b2293b71b9c746c79ca (patch)
treea1fd77581f6275843d0305a966d42d5b1b4748cf /block
parentMerge tag 'io_uring-5.19-2022-06-02' of git://git.kernel.dk/linux-block (diff)
parentblock: Fix potential deadlock in blk_ia_range_sysfs_show() (diff)
downloadlinux-34845d92bca527b5c2cf8b2293b71b9c746c79ca.tar.xz
linux-34845d92bca527b5c2cf8b2293b71b9c746c79ca.zip
Merge tag 'for-5.19/block-2022-06-02' of git://git.kernel.dk/linux-block
Pull block fixes from Jens Axboe: "Just a collection of fixes that have been queued up since the initial merge window pull request, the majority of which are targeted for stable as well. One bio_set fix that fixes an issue with the dm adoption of cached bio structs that got introduced in this merge window" * tag 'for-5.19/block-2022-06-02' of git://git.kernel.dk/linux-block: block: Fix potential deadlock in blk_ia_range_sysfs_show() block: fix bio_clone_blkg_association() to associate with proper blkcg_gq block: remove useless BUG_ON() in blk_mq_put_tag() blk-mq: do not update io_ticks with passthrough requests block: make bioset_exit() fully resilient against being called twice block: use bio_queue_enter instead of blk_queue_enter in bio_poll block: document BLK_STS_AGAIN usage block: take destination bvec offsets into account in bio_copy_data_iter blk-iolatency: Fix inflight count imbalances and IO hangs on offline blk-mq: don't touch ->tagset in blk_mq_get_sq_hctx
Diffstat (limited to 'block')
-rw-r--r--block/bio.c9
-rw-r--r--block/blk-cgroup.c8
-rw-r--r--block/blk-core.c2
-rw-r--r--block/blk-ia-ranges.c7
-rw-r--r--block/blk-iolatency.c122
-rw-r--r--block/blk-mq-tag.c1
-rw-r--r--block/blk-mq.c10
7 files changed, 79 insertions, 80 deletions
diff --git a/block/bio.c b/block/bio.c
index a3893d80dccc..f92d0223247b 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -722,6 +722,7 @@ static void bio_alloc_cache_destroy(struct bio_set *bs)
bio_alloc_cache_prune(cache, -1U);
}
free_percpu(bs->cache);
+ bs->cache = NULL;
}
/**
@@ -1366,10 +1367,12 @@ void bio_copy_data_iter(struct bio *dst, struct bvec_iter *dst_iter,
struct bio_vec src_bv = bio_iter_iovec(src, *src_iter);
struct bio_vec dst_bv = bio_iter_iovec(dst, *dst_iter);
unsigned int bytes = min(src_bv.bv_len, dst_bv.bv_len);
- void *src_buf;
+ void *src_buf = bvec_kmap_local(&src_bv);
+ void *dst_buf = bvec_kmap_local(&dst_bv);
- src_buf = bvec_kmap_local(&src_bv);
- memcpy_to_bvec(&dst_bv, src_buf);
+ memcpy(dst_buf, src_buf, bytes);
+
+ kunmap_local(dst_buf);
kunmap_local(src_buf);
bio_advance_iter_single(src, src_iter, bytes);
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 40161a3f68d0..764e740b0c0f 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -1974,12 +1974,8 @@ EXPORT_SYMBOL_GPL(bio_associate_blkg);
*/
void bio_clone_blkg_association(struct bio *dst, struct bio *src)
{
- if (src->bi_blkg) {
- if (dst->bi_blkg)
- blkg_put(dst->bi_blkg);
- blkg_get(src->bi_blkg);
- dst->bi_blkg = src->bi_blkg;
- }
+ if (src->bi_blkg)
+ bio_associate_blkg_from_css(dst, bio_blkcg_css(src));
}
EXPORT_SYMBOL_GPL(bio_clone_blkg_association);
diff --git a/block/blk-core.c b/block/blk-core.c
index 80fa73c419a9..06ff5bbfe8f6 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -939,7 +939,7 @@ int bio_poll(struct bio *bio, struct io_comp_batch *iob, unsigned int flags)
blk_flush_plug(current->plug, false);
- if (blk_queue_enter(q, BLK_MQ_REQ_NOWAIT))
+ if (bio_queue_enter(bio))
return 0;
if (queue_is_mq(q)) {
ret = blk_mq_poll(q, cookie, iob, flags);
diff --git a/block/blk-ia-ranges.c b/block/blk-ia-ranges.c
index 18c68d8b9138..56ed48d2954e 100644
--- a/block/blk-ia-ranges.c
+++ b/block/blk-ia-ranges.c
@@ -54,13 +54,8 @@ static ssize_t blk_ia_range_sysfs_show(struct kobject *kobj,
container_of(attr, struct blk_ia_range_sysfs_entry, attr);
struct blk_independent_access_range *iar =
container_of(kobj, struct blk_independent_access_range, kobj);
- ssize_t ret;
- mutex_lock(&iar->queue->sysfs_lock);
- ret = entry->show(iar, buf);
- mutex_unlock(&iar->queue->sysfs_lock);
-
- return ret;
+ return entry->show(iar, buf);
}
static const struct sysfs_ops blk_ia_range_sysfs_ops = {
diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
index 5b676c7cf2b6..9568bf8dfe82 100644
--- a/block/blk-iolatency.c
+++ b/block/blk-iolatency.c
@@ -87,7 +87,17 @@ struct iolatency_grp;
struct blk_iolatency {
struct rq_qos rqos;
struct timer_list timer;
- atomic_t enabled;
+
+ /*
+ * ->enabled is the master enable switch gating the throttling logic and
+ * inflight tracking. The number of cgroups which have iolat enabled is
+ * tracked in ->enable_cnt, and ->enable is flipped on/off accordingly
+ * from ->enable_work with the request_queue frozen. For details, See
+ * blkiolatency_enable_work_fn().
+ */
+ bool enabled;
+ atomic_t enable_cnt;
+ struct work_struct enable_work;
};
static inline struct blk_iolatency *BLKIOLATENCY(struct rq_qos *rqos)
@@ -95,11 +105,6 @@ static inline struct blk_iolatency *BLKIOLATENCY(struct rq_qos *rqos)
return container_of(rqos, struct blk_iolatency, rqos);
}
-static inline bool blk_iolatency_enabled(struct blk_iolatency *blkiolat)
-{
- return atomic_read(&blkiolat->enabled) > 0;
-}
-
struct child_latency_info {
spinlock_t lock;
@@ -464,7 +469,7 @@ static void blkcg_iolatency_throttle(struct rq_qos *rqos, struct bio *bio)
struct blkcg_gq *blkg = bio->bi_blkg;
bool issue_as_root = bio_issue_as_root_blkg(bio);
- if (!blk_iolatency_enabled(blkiolat))
+ if (!blkiolat->enabled)
return;
while (blkg && blkg->parent) {
@@ -594,7 +599,6 @@ static void blkcg_iolatency_done_bio(struct rq_qos *rqos, struct bio *bio)
u64 window_start;
u64 now;
bool issue_as_root = bio_issue_as_root_blkg(bio);
- bool enabled = false;
int inflight = 0;
blkg = bio->bi_blkg;
@@ -605,8 +609,7 @@ static void blkcg_iolatency_done_bio(struct rq_qos *rqos, struct bio *bio)
if (!iolat)
return;
- enabled = blk_iolatency_enabled(iolat->blkiolat);
- if (!enabled)
+ if (!iolat->blkiolat->enabled)
return;
now = ktime_to_ns(ktime_get());
@@ -645,6 +648,7 @@ static void blkcg_iolatency_exit(struct rq_qos *rqos)
struct blk_iolatency *blkiolat = BLKIOLATENCY(rqos);
del_timer_sync(&blkiolat->timer);
+ flush_work(&blkiolat->enable_work);
blkcg_deactivate_policy(rqos->q, &blkcg_policy_iolatency);
kfree(blkiolat);
}
@@ -716,6 +720,44 @@ next:
rcu_read_unlock();
}
+/**
+ * blkiolatency_enable_work_fn - Enable or disable iolatency on the device
+ * @work: enable_work of the blk_iolatency of interest
+ *
+ * iolatency needs to keep track of the number of in-flight IOs per cgroup. This
+ * is relatively expensive as it involves walking up the hierarchy twice for
+ * every IO. Thus, if iolatency is not enabled in any cgroup for the device, we
+ * want to disable the in-flight tracking.
+ *
+ * We have to make sure that the counting is balanced - we don't want to leak
+ * the in-flight counts by disabling accounting in the completion path while IOs
+ * are in flight. This is achieved by ensuring that no IO is in flight by
+ * freezing the queue while flipping ->enabled. As this requires a sleepable
+ * context, ->enabled flipping is punted to this work function.
+ */
+static void blkiolatency_enable_work_fn(struct work_struct *work)
+{
+ struct blk_iolatency *blkiolat = container_of(work, struct blk_iolatency,
+ enable_work);
+ bool enabled;
+
+ /*
+ * There can only be one instance of this function running for @blkiolat
+ * and it's guaranteed to be executed at least once after the latest
+ * ->enabled_cnt modification. Acting on the latest ->enable_cnt is
+ * sufficient.
+ *
+ * Also, we know @blkiolat is safe to access as ->enable_work is flushed
+ * in blkcg_iolatency_exit().
+ */
+ enabled = atomic_read(&blkiolat->enable_cnt);
+ if (enabled != blkiolat->enabled) {
+ blk_mq_freeze_queue(blkiolat->rqos.q);
+ blkiolat->enabled = enabled;
+ blk_mq_unfreeze_queue(blkiolat->rqos.q);
+ }
+}
+
int blk_iolatency_init(struct request_queue *q)
{
struct blk_iolatency *blkiolat;
@@ -741,17 +783,15 @@ int blk_iolatency_init(struct request_queue *q)
}
timer_setup(&blkiolat->timer, blkiolatency_timer_fn, 0);
+ INIT_WORK(&blkiolat->enable_work, blkiolatency_enable_work_fn);
return 0;
}
-/*
- * return 1 for enabling iolatency, return -1 for disabling iolatency, otherwise
- * return 0.
- */
-static int iolatency_set_min_lat_nsec(struct blkcg_gq *blkg, u64 val)
+static void iolatency_set_min_lat_nsec(struct blkcg_gq *blkg, u64 val)
{
struct iolatency_grp *iolat = blkg_to_lat(blkg);
+ struct blk_iolatency *blkiolat = iolat->blkiolat;
u64 oldval = iolat->min_lat_nsec;
iolat->min_lat_nsec = val;
@@ -759,13 +799,15 @@ static int iolatency_set_min_lat_nsec(struct blkcg_gq *blkg, u64 val)
iolat->cur_win_nsec = min_t(u64, iolat->cur_win_nsec,
BLKIOLATENCY_MAX_WIN_SIZE);
- if (!oldval && val)
- return 1;
+ if (!oldval && val) {
+ if (atomic_inc_return(&blkiolat->enable_cnt) == 1)
+ schedule_work(&blkiolat->enable_work);
+ }
if (oldval && !val) {
blkcg_clear_delay(blkg);
- return -1;
+ if (atomic_dec_return(&blkiolat->enable_cnt) == 0)
+ schedule_work(&blkiolat->enable_work);
}
- return 0;
}
static void iolatency_clear_scaling(struct blkcg_gq *blkg)
@@ -797,7 +839,6 @@ static ssize_t iolatency_set_limit(struct kernfs_open_file *of, char *buf,
u64 lat_val = 0;
u64 oldval;
int ret;
- int enable = 0;
ret = blkg_conf_prep(blkcg, &blkcg_policy_iolatency, buf, &ctx);
if (ret)
@@ -832,41 +873,12 @@ static ssize_t iolatency_set_limit(struct kernfs_open_file *of, char *buf,
blkg = ctx.blkg;
oldval = iolat->min_lat_nsec;
- enable = iolatency_set_min_lat_nsec(blkg, lat_val);
- if (enable) {
- if (!blk_get_queue(blkg->q)) {
- ret = -ENODEV;
- goto out;
- }
-
- blkg_get(blkg);
- }
-
- if (oldval != iolat->min_lat_nsec) {
+ iolatency_set_min_lat_nsec(blkg, lat_val);
+ if (oldval != iolat->min_lat_nsec)
iolatency_clear_scaling(blkg);
- }
-
ret = 0;
out:
blkg_conf_finish(&ctx);
- if (ret == 0 && enable) {
- struct iolatency_grp *tmp = blkg_to_lat(blkg);
- struct blk_iolatency *blkiolat = tmp->blkiolat;
-
- blk_mq_freeze_queue(blkg->q);
-
- if (enable == 1)
- atomic_inc(&blkiolat->enabled);
- else if (enable == -1)
- atomic_dec(&blkiolat->enabled);
- else
- WARN_ON_ONCE(1);
-
- blk_mq_unfreeze_queue(blkg->q);
-
- blkg_put(blkg);
- blk_put_queue(blkg->q);
- }
return ret ?: nbytes;
}
@@ -1005,14 +1017,8 @@ static void iolatency_pd_offline(struct blkg_policy_data *pd)
{
struct iolatency_grp *iolat = pd_to_lat(pd);
struct blkcg_gq *blkg = lat_to_blkg(iolat);
- struct blk_iolatency *blkiolat = iolat->blkiolat;
- int ret;
- ret = iolatency_set_min_lat_nsec(blkg, 0);
- if (ret == 1)
- atomic_inc(&blkiolat->enabled);
- if (ret == -1)
- atomic_dec(&blkiolat->enabled);
+ iolatency_set_min_lat_nsec(blkg, 0);
iolatency_clear_scaling(blkg);
}
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index 68ac23d0b640..2dcd738c6952 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -228,7 +228,6 @@ void blk_mq_put_tag(struct blk_mq_tags *tags, struct blk_mq_ctx *ctx,
BUG_ON(real_tag >= tags->nr_tags);
sbitmap_queue_clear(&tags->bitmap_tags, real_tag, ctx->cpu);
} else {
- BUG_ON(tag >= tags->nr_reserved_tags);
sbitmap_queue_clear(&tags->breserved_tags, tag, ctx->cpu);
}
}
diff --git a/block/blk-mq.c b/block/blk-mq.c
index ae116b755648..30e4bdcd8d7f 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -133,7 +133,8 @@ static bool blk_mq_check_inflight(struct request *rq, void *priv,
{
struct mq_inflight *mi = priv;
- if ((!mi->part->bd_partno || rq->part == mi->part) &&
+ if (rq->part && blk_do_io_stat(rq) &&
+ (!mi->part->bd_partno || rq->part == mi->part) &&
blk_mq_rq_state(rq) == MQ_RQ_IN_FLIGHT)
mi->inflight[rq_data_dir(rq)]++;
@@ -2174,8 +2175,7 @@ static bool blk_mq_has_sqsched(struct request_queue *q)
*/
static struct blk_mq_hw_ctx *blk_mq_get_sq_hctx(struct request_queue *q)
{
- struct blk_mq_hw_ctx *hctx;
-
+ struct blk_mq_ctx *ctx = blk_mq_get_ctx(q);
/*
* If the IO scheduler does not respect hardware queues when
* dispatching, we just don't bother with multiple HW queues and
@@ -2183,8 +2183,8 @@ static struct blk_mq_hw_ctx *blk_mq_get_sq_hctx(struct request_queue *q)
* just causes lock contention inside the scheduler and pointless cache
* bouncing.
*/
- hctx = blk_mq_map_queue_type(q, HCTX_TYPE_DEFAULT,
- raw_smp_processor_id());
+ struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, 0, ctx);
+
if (!blk_mq_hctx_stopped(hctx))
return hctx;
return NULL;