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authorLinus Torvalds <torvalds@linux-foundation.org>2020-02-28 11:43:30 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2020-02-28 11:43:30 -0800
commit2edc78b9a4b868d7bfee4f87ea29f2df19b6e955 (patch)
treee719289213d2691ad2a89a9576f72e9b670cbf74
parent74dea5d99d19236608914d2c556134e4cdc21c60 (diff)
parent5b8ea58b6a338cb981670c4408225331aedb4b89 (diff)
Merge tag 'block-5.6-2020-02-28' of git://git.kernel.dk/linux-block
Pull block fixes from Jens Axboe: - Passthrough insertion fix (Ming) - Kill off some unused arguments (John) - blktrace RCU fix (Jan) - Dead fields removal for null_blk (Dongli) - NVMe polled IO fix (Bijan) * tag 'block-5.6-2020-02-28' of git://git.kernel.dk/linux-block: nvme-pci: Hold cq_poll_lock while completing CQEs blk-mq: Remove some unused function arguments null_blk: remove unused fields in 'nullb_cmd' blktrace: Protect q->blk_trace with RCU blk-mq: insert passthrough request into hctx->dispatch directly
-rw-r--r--block/blk-flush.c2
-rw-r--r--block/blk-mq-sched.c22
-rw-r--r--block/blk-mq-tag.c4
-rw-r--r--block/blk-mq-tag.h4
-rw-r--r--block/blk-mq.c28
-rw-r--r--block/blk-mq.h5
-rw-r--r--drivers/block/null_blk.h3
-rw-r--r--drivers/block/null_blk_main.c2
-rw-r--r--drivers/nvme/host/pci.c2
-rw-r--r--include/linux/blkdev.h2
-rw-r--r--include/linux/blktrace_api.h18
-rw-r--r--kernel/trace/blktrace.c114
12 files changed, 136 insertions, 70 deletions
diff --git a/block/blk-flush.c b/block/blk-flush.c
index 3f977c517960..5cc775bdb06a 100644
--- a/block/blk-flush.c
+++ b/block/blk-flush.c
@@ -412,7 +412,7 @@ void blk_insert_flush(struct request *rq)
*/
if ((policy & REQ_FSEQ_DATA) &&
!(policy & (REQ_FSEQ_PREFLUSH | REQ_FSEQ_POSTFLUSH))) {
- blk_mq_request_bypass_insert(rq, false);
+ blk_mq_request_bypass_insert(rq, false, false);
return;
}
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index ca22afd47b3d..856356b1619e 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -361,13 +361,19 @@ static bool blk_mq_sched_bypass_insert(struct blk_mq_hw_ctx *hctx,
bool has_sched,
struct request *rq)
{
- /* dispatch flush rq directly */
- if (rq->rq_flags & RQF_FLUSH_SEQ) {
- spin_lock(&hctx->lock);
- list_add(&rq->queuelist, &hctx->dispatch);
- spin_unlock(&hctx->lock);
+ /*
+ * dispatch flush and passthrough rq directly
+ *
+ * passthrough request has to be added to hctx->dispatch directly.
+ * For some reason, device may be in one situation which can't
+ * handle FS request, so STS_RESOURCE is always returned and the
+ * FS request will be added to hctx->dispatch. However passthrough
+ * request may be required at that time for fixing the problem. If
+ * passthrough request is added to scheduler queue, there isn't any
+ * chance to dispatch it given we prioritize requests in hctx->dispatch.
+ */
+ if ((rq->rq_flags & RQF_FLUSH_SEQ) || blk_rq_is_passthrough(rq))
return true;
- }
if (has_sched)
rq->rq_flags |= RQF_SORTED;
@@ -391,8 +397,10 @@ void blk_mq_sched_insert_request(struct request *rq, bool at_head,
WARN_ON(e && (rq->tag != -1));
- if (blk_mq_sched_bypass_insert(hctx, !!e, rq))
+ if (blk_mq_sched_bypass_insert(hctx, !!e, rq)) {
+ blk_mq_request_bypass_insert(rq, at_head, false);
goto run;
+ }
if (e && e->type->ops.insert_requests) {
LIST_HEAD(list);
diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c
index fbacde454718..586c9d6e904a 100644
--- a/block/blk-mq-tag.c
+++ b/block/blk-mq-tag.c
@@ -183,8 +183,8 @@ found_tag:
return tag + tag_offset;
}
-void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx, struct blk_mq_tags *tags,
- struct blk_mq_ctx *ctx, unsigned int tag)
+void blk_mq_put_tag(struct blk_mq_tags *tags, struct blk_mq_ctx *ctx,
+ unsigned int tag)
{
if (!blk_mq_tag_is_reserved(tags, tag)) {
const int real_tag = tag - tags->nr_reserved_tags;
diff --git a/block/blk-mq-tag.h b/block/blk-mq-tag.h
index 15bc74acb57e..2b8321efb682 100644
--- a/block/blk-mq-tag.h
+++ b/block/blk-mq-tag.h
@@ -26,8 +26,8 @@ extern struct blk_mq_tags *blk_mq_init_tags(unsigned int nr_tags, unsigned int r
extern void blk_mq_free_tags(struct blk_mq_tags *tags);
extern unsigned int blk_mq_get_tag(struct blk_mq_alloc_data *data);
-extern void blk_mq_put_tag(struct blk_mq_hw_ctx *hctx, struct blk_mq_tags *tags,
- struct blk_mq_ctx *ctx, unsigned int tag);
+extern void blk_mq_put_tag(struct blk_mq_tags *tags, struct blk_mq_ctx *ctx,
+ unsigned int tag);
extern int blk_mq_tag_update_depth(struct blk_mq_hw_ctx *hctx,
struct blk_mq_tags **tags,
unsigned int depth, bool can_grow);
diff --git a/block/blk-mq.c b/block/blk-mq.c
index a12b1763508d..d92088dec6c3 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -477,9 +477,9 @@ static void __blk_mq_free_request(struct request *rq)
blk_pm_mark_last_busy(rq);
rq->mq_hctx = NULL;
if (rq->tag != -1)
- blk_mq_put_tag(hctx, hctx->tags, ctx, rq->tag);
+ blk_mq_put_tag(hctx->tags, ctx, rq->tag);
if (sched_tag != -1)
- blk_mq_put_tag(hctx, hctx->sched_tags, ctx, sched_tag);
+ blk_mq_put_tag(hctx->sched_tags, ctx, sched_tag);
blk_mq_sched_restart(hctx);
blk_queue_exit(q);
}
@@ -735,7 +735,7 @@ static void blk_mq_requeue_work(struct work_struct *work)
* merge.
*/
if (rq->rq_flags & RQF_DONTPREP)
- blk_mq_request_bypass_insert(rq, false);
+ blk_mq_request_bypass_insert(rq, false, false);
else
blk_mq_sched_insert_request(rq, true, false, false);
}
@@ -1286,7 +1286,7 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list,
q->mq_ops->commit_rqs(hctx);
spin_lock(&hctx->lock);
- list_splice_init(list, &hctx->dispatch);
+ list_splice_tail_init(list, &hctx->dispatch);
spin_unlock(&hctx->lock);
/*
@@ -1677,12 +1677,16 @@ void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
* Should only be used carefully, when the caller knows we want to
* bypass a potential IO scheduler on the target device.
*/
-void blk_mq_request_bypass_insert(struct request *rq, bool run_queue)
+void blk_mq_request_bypass_insert(struct request *rq, bool at_head,
+ bool run_queue)
{
struct blk_mq_hw_ctx *hctx = rq->mq_hctx;
spin_lock(&hctx->lock);
- list_add_tail(&rq->queuelist, &hctx->dispatch);
+ if (at_head)
+ list_add(&rq->queuelist, &hctx->dispatch);
+ else
+ list_add_tail(&rq->queuelist, &hctx->dispatch);
spin_unlock(&hctx->lock);
if (run_queue)
@@ -1849,7 +1853,7 @@ insert:
if (bypass_insert)
return BLK_STS_RESOURCE;
- blk_mq_request_bypass_insert(rq, run_queue);
+ blk_mq_request_bypass_insert(rq, false, run_queue);
return BLK_STS_OK;
}
@@ -1876,7 +1880,7 @@ static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
ret = __blk_mq_try_issue_directly(hctx, rq, cookie, false, true);
if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE)
- blk_mq_request_bypass_insert(rq, true);
+ blk_mq_request_bypass_insert(rq, false, true);
else if (ret != BLK_STS_OK)
blk_mq_end_request(rq, ret);
@@ -1910,7 +1914,7 @@ void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
if (ret != BLK_STS_OK) {
if (ret == BLK_STS_RESOURCE ||
ret == BLK_STS_DEV_RESOURCE) {
- blk_mq_request_bypass_insert(rq,
+ blk_mq_request_bypass_insert(rq, false,
list_empty(list));
break;
}
@@ -3398,7 +3402,6 @@ static void blk_mq_poll_stats_fn(struct blk_stat_callback *cb)
}
static unsigned long blk_mq_poll_nsecs(struct request_queue *q,
- struct blk_mq_hw_ctx *hctx,
struct request *rq)
{
unsigned long ret = 0;
@@ -3431,7 +3434,6 @@ static unsigned long blk_mq_poll_nsecs(struct request_queue *q,
}
static bool blk_mq_poll_hybrid_sleep(struct request_queue *q,
- struct blk_mq_hw_ctx *hctx,
struct request *rq)
{
struct hrtimer_sleeper hs;
@@ -3451,7 +3453,7 @@ static bool blk_mq_poll_hybrid_sleep(struct request_queue *q,
if (q->poll_nsec > 0)
nsecs = q->poll_nsec;
else
- nsecs = blk_mq_poll_nsecs(q, hctx, rq);
+ nsecs = blk_mq_poll_nsecs(q, rq);
if (!nsecs)
return false;
@@ -3506,7 +3508,7 @@ static bool blk_mq_poll_hybrid(struct request_queue *q,
return false;
}
- return blk_mq_poll_hybrid_sleep(q, hctx, rq);
+ return blk_mq_poll_hybrid_sleep(q, rq);
}
/**
diff --git a/block/blk-mq.h b/block/blk-mq.h
index eaaca8fc1c28..10bfdfb494fa 100644
--- a/block/blk-mq.h
+++ b/block/blk-mq.h
@@ -66,7 +66,8 @@ int blk_mq_alloc_rqs(struct blk_mq_tag_set *set, struct blk_mq_tags *tags,
*/
void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq,
bool at_head);
-void blk_mq_request_bypass_insert(struct request *rq, bool run_queue);
+void blk_mq_request_bypass_insert(struct request *rq, bool at_head,
+ bool run_queue);
void blk_mq_insert_requests(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *ctx,
struct list_head *list);
@@ -199,7 +200,7 @@ static inline bool blk_mq_get_dispatch_budget(struct blk_mq_hw_ctx *hctx)
static inline void __blk_mq_put_driver_tag(struct blk_mq_hw_ctx *hctx,
struct request *rq)
{
- blk_mq_put_tag(hctx, hctx->tags, rq->mq_ctx, rq->tag);
+ blk_mq_put_tag(hctx->tags, rq->mq_ctx, rq->tag);
rq->tag = -1;
if (rq->rq_flags & RQF_MQ_INFLIGHT) {
diff --git a/drivers/block/null_blk.h b/drivers/block/null_blk.h
index bc837862b767..62b660821dbc 100644
--- a/drivers/block/null_blk.h
+++ b/drivers/block/null_blk.h
@@ -14,9 +14,6 @@
#include <linux/fault-inject.h>
struct nullb_cmd {
- struct list_head list;
- struct llist_node ll_list;
- struct __call_single_data csd;
struct request *rq;
struct bio *bio;
unsigned int tag;
diff --git a/drivers/block/null_blk_main.c b/drivers/block/null_blk_main.c
index 16510795e377..133060431dbd 100644
--- a/drivers/block/null_blk_main.c
+++ b/drivers/block/null_blk_main.c
@@ -1518,8 +1518,6 @@ static int setup_commands(struct nullb_queue *nq)
for (i = 0; i < nq->queue_depth; i++) {
cmd = &nq->cmds[i];
- INIT_LIST_HEAD(&cmd->list);
- cmd->ll_list.next = NULL;
cmd->tag = -1U;
}
diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c
index ace4dd9e953c..d3f23d6254e4 100644
--- a/drivers/nvme/host/pci.c
+++ b/drivers/nvme/host/pci.c
@@ -1078,9 +1078,9 @@ static int nvme_poll(struct blk_mq_hw_ctx *hctx)
spin_lock(&nvmeq->cq_poll_lock);
found = nvme_process_cq(nvmeq, &start, &end, -1);
+ nvme_complete_cqes(nvmeq, start, end);
spin_unlock(&nvmeq->cq_poll_lock);
- nvme_complete_cqes(nvmeq, start, end);
return found;
}
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 053ea4b51988..10455b2bbbb4 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -524,7 +524,7 @@ struct request_queue {
unsigned int sg_reserved_size;
int node;
#ifdef CONFIG_BLK_DEV_IO_TRACE
- struct blk_trace *blk_trace;
+ struct blk_trace __rcu *blk_trace;
struct mutex blk_trace_mutex;
#endif
/*
diff --git a/include/linux/blktrace_api.h b/include/linux/blktrace_api.h
index 7bb2d8de9f30..3b6ff5902edc 100644
--- a/include/linux/blktrace_api.h
+++ b/include/linux/blktrace_api.h
@@ -51,9 +51,13 @@ void __trace_note_message(struct blk_trace *, struct blkcg *blkcg, const char *f
**/
#define blk_add_cgroup_trace_msg(q, cg, fmt, ...) \
do { \
- struct blk_trace *bt = (q)->blk_trace; \
+ struct blk_trace *bt; \
+ \
+ rcu_read_lock(); \
+ bt = rcu_dereference((q)->blk_trace); \
if (unlikely(bt)) \
__trace_note_message(bt, cg, fmt, ##__VA_ARGS__);\
+ rcu_read_unlock(); \
} while (0)
#define blk_add_trace_msg(q, fmt, ...) \
blk_add_cgroup_trace_msg(q, NULL, fmt, ##__VA_ARGS__)
@@ -61,10 +65,14 @@ void __trace_note_message(struct blk_trace *, struct blkcg *blkcg, const char *f
static inline bool blk_trace_note_message_enabled(struct request_queue *q)
{
- struct blk_trace *bt = q->blk_trace;
- if (likely(!bt))
- return false;
- return bt->act_mask & BLK_TC_NOTIFY;
+ struct blk_trace *bt;
+ bool ret;
+
+ rcu_read_lock();
+ bt = rcu_dereference(q->blk_trace);
+ ret = bt && (bt->act_mask & BLK_TC_NOTIFY);
+ rcu_read_unlock();
+ return ret;
}
extern void blk_add_driver_data(struct request_queue *q, struct request *rq,
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 0735ae8545d8..4560878f0bac 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -335,6 +335,7 @@ static void put_probe_ref(void)
static void blk_trace_cleanup(struct blk_trace *bt)
{
+ synchronize_rcu();
blk_trace_free(bt);
put_probe_ref();
}
@@ -629,8 +630,10 @@ static int compat_blk_trace_setup(struct request_queue *q, char *name,
static int __blk_trace_startstop(struct request_queue *q, int start)
{
int ret;
- struct blk_trace *bt = q->blk_trace;
+ struct blk_trace *bt;
+ bt = rcu_dereference_protected(q->blk_trace,
+ lockdep_is_held(&q->blk_trace_mutex));
if (bt == NULL)
return -EINVAL;
@@ -740,8 +743,8 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
void blk_trace_shutdown(struct request_queue *q)
{
mutex_lock(&q->blk_trace_mutex);
-
- if (q->blk_trace) {
+ if (rcu_dereference_protected(q->blk_trace,
+ lockdep_is_held(&q->blk_trace_mutex))) {
__blk_trace_startstop(q, 0);
__blk_trace_remove(q);
}
@@ -752,8 +755,10 @@ void blk_trace_shutdown(struct request_queue *q)
#ifdef CONFIG_BLK_CGROUP
static u64 blk_trace_bio_get_cgid(struct request_queue *q, struct bio *bio)
{
- struct blk_trace *bt = q->blk_trace;
+ struct blk_trace *bt;
+ /* We don't use the 'bt' value here except as an optimization... */
+ bt = rcu_dereference_protected(q->blk_trace, 1);
if (!bt || !(blk_tracer_flags.val & TRACE_BLK_OPT_CGROUP))
return 0;
@@ -796,10 +801,14 @@ blk_trace_request_get_cgid(struct request_queue *q, struct request *rq)
static void blk_add_trace_rq(struct request *rq, int error,
unsigned int nr_bytes, u32 what, u64 cgid)
{
- struct blk_trace *bt = rq->q->blk_trace;
+ struct blk_trace *bt;
- if (likely(!bt))
+ rcu_read_lock();
+ bt = rcu_dereference(rq->q->blk_trace);
+ if (likely(!bt)) {
+ rcu_read_unlock();
return;
+ }
if (blk_rq_is_passthrough(rq))
what |= BLK_TC_ACT(BLK_TC_PC);
@@ -808,6 +817,7 @@ static void blk_add_trace_rq(struct request *rq, int error,
__blk_add_trace(bt, blk_rq_trace_sector(rq), nr_bytes, req_op(rq),
rq->cmd_flags, what, error, 0, NULL, cgid);
+ rcu_read_unlock();
}
static void blk_add_trace_rq_insert(void *ignore,
@@ -853,14 +863,19 @@ static void blk_add_trace_rq_complete(void *ignore, struct request *rq,
static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
u32 what, int error)
{
- struct blk_trace *bt = q->blk_trace;
+ struct blk_trace *bt;
- if (likely(!bt))
+ rcu_read_lock();
+ bt = rcu_dereference(q->blk_trace);
+ if (likely(!bt)) {
+ rcu_read_unlock();
return;
+ }
__blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
bio_op(bio), bio->bi_opf, what, error, 0, NULL,
blk_trace_bio_get_cgid(q, bio));
+ rcu_read_unlock();
}
static void blk_add_trace_bio_bounce(void *ignore,
@@ -905,11 +920,14 @@ static void blk_add_trace_getrq(void *ignore,
if (bio)
blk_add_trace_bio(q, bio, BLK_TA_GETRQ, 0);
else {
- struct blk_trace *bt = q->blk_trace;
+ struct blk_trace *bt;
+ rcu_read_lock();
+ bt = rcu_dereference(q->blk_trace);
if (bt)
__blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_GETRQ, 0, 0,
NULL, 0);
+ rcu_read_unlock();
}
}
@@ -921,27 +939,35 @@ static void blk_add_trace_sleeprq(void *ignore,
if (bio)
blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ, 0);
else {
- struct blk_trace *bt = q->blk_trace;
+ struct blk_trace *bt;
+ rcu_read_lock();
+ bt = rcu_dereference(q->blk_trace);
if (bt)
__blk_add_trace(bt, 0, 0, rw, 0, BLK_TA_SLEEPRQ,
0, 0, NULL, 0);
+ rcu_read_unlock();
}
}
static void blk_add_trace_plug(void *ignore, struct request_queue *q)
{
- struct blk_trace *bt = q->blk_trace;
+ struct blk_trace *bt;
+ rcu_read_lock();
+ bt = rcu_dereference(q->blk_trace);
if (bt)
__blk_add_trace(bt, 0, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL, 0);
+ rcu_read_unlock();
}
static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
unsigned int depth, bool explicit)
{
- struct blk_trace *bt = q->blk_trace;
+ struct blk_trace *bt;
+ rcu_read_lock();
+ bt = rcu_dereference(q->blk_trace);
if (bt) {
__be64 rpdu = cpu_to_be64(depth);
u32 what;
@@ -953,14 +979,17 @@ static void blk_add_trace_unplug(void *ignore, struct request_queue *q,
__blk_add_trace(bt, 0, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu, 0);
}
+ rcu_read_unlock();
}
static void blk_add_trace_split(void *ignore,
struct request_queue *q, struct bio *bio,
unsigned int pdu)
{
- struct blk_trace *bt = q->blk_trace;
+ struct blk_trace *bt;
+ rcu_read_lock();
+ bt = rcu_dereference(q->blk_trace);
if (bt) {
__be64 rpdu = cpu_to_be64(pdu);
@@ -969,6 +998,7 @@ static void blk_add_trace_split(void *ignore,
BLK_TA_SPLIT, bio->bi_status, sizeof(rpdu),
&rpdu, blk_trace_bio_get_cgid(q, bio));
}
+ rcu_read_unlock();
}
/**
@@ -988,11 +1018,15 @@ static void blk_add_trace_bio_remap(void *ignore,
struct request_queue *q, struct bio *bio,
dev_t dev, sector_t from)
{
- struct blk_trace *bt = q->blk_trace;
+ struct blk_trace *bt;
struct blk_io_trace_remap r;
- if (likely(!bt))
+ rcu_read_lock();
+ bt = rcu_dereference(q->blk_trace);
+ if (likely(!bt)) {
+ rcu_read_unlock();
return;
+ }
r.device_from = cpu_to_be32(dev);
r.device_to = cpu_to_be32(bio_dev(bio));
@@ -1001,6 +1035,7 @@ static void blk_add_trace_bio_remap(void *ignore,
__blk_add_trace(bt, bio->bi_iter.bi_sector, bio->bi_iter.bi_size,
bio_op(bio), bio->bi_opf, BLK_TA_REMAP, bio->bi_status,
sizeof(r), &r, blk_trace_bio_get_cgid(q, bio));
+ rcu_read_unlock();
}
/**
@@ -1021,11 +1056,15 @@ static void blk_add_trace_rq_remap(void *ignore,
struct request *rq, dev_t dev,
sector_t from)
{
- struct blk_trace *bt = q->blk_trace;
+ struct blk_trace *bt;
struct blk_io_trace_remap r;
- if (likely(!bt))
+ rcu_read_lock();
+ bt = rcu_dereference(q->blk_trace);
+ if (likely(!bt)) {
+ rcu_read_unlock();
return;
+ }
r.device_from = cpu_to_be32(dev);
r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
@@ -1034,6 +1073,7 @@ static void blk_add_trace_rq_remap(void *ignore,
__blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
rq_data_dir(rq), 0, BLK_TA_REMAP, 0,
sizeof(r), &r, blk_trace_request_get_cgid(q, rq));
+ rcu_read_unlock();
}
/**
@@ -1051,14 +1091,19 @@ void blk_add_driver_data(struct request_queue *q,
struct request *rq,
void *data, size_t len)
{
- struct blk_trace *bt = q->blk_trace;
+ struct blk_trace *bt;
- if (likely(!bt))
+ rcu_read_lock();
+ bt = rcu_dereference(q->blk_trace);
+ if (likely(!bt)) {
+ rcu_read_unlock();
return;
+ }
__blk_add_trace(bt, blk_rq_trace_sector(rq), blk_rq_bytes(rq), 0, 0,
BLK_TA_DRV_DATA, 0, len, data,
blk_trace_request_get_cgid(q, rq));
+ rcu_read_unlock();
}
EXPORT_SYMBOL_GPL(blk_add_driver_data);
@@ -1597,6 +1642,7 @@ static int blk_trace_remove_queue(struct request_queue *q)
return -EINVAL;
put_probe_ref();
+ synchronize_rcu();
blk_trace_free(bt);
return 0;
}
@@ -1758,6 +1804,7 @@ static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
struct hd_struct *p = dev_to_part(dev);
struct request_queue *q;
struct block_device *bdev;
+ struct blk_trace *bt;
ssize_t ret = -ENXIO;
bdev = bdget(part_devt(p));
@@ -1770,21 +1817,23 @@ static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
mutex_lock(&q->blk_trace_mutex);
+ bt = rcu_dereference_protected(q->blk_trace,
+ lockdep_is_held(&q->blk_trace_mutex));
if (attr == &dev_attr_enable) {
- ret = sprintf(buf, "%u\n", !!q->blk_trace);
+ ret = sprintf(buf, "%u\n", !!bt);
goto out_unlock_bdev;
}
- if (q->blk_trace == NULL)
+ if (bt == NULL)
ret = sprintf(buf, "disabled\n");
else if (attr == &dev_attr_act_mask)
- ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
+ ret = blk_trace_mask2str(buf, bt->act_mask);
else if (attr == &dev_attr_pid)
- ret = sprintf(buf, "%u\n", q->blk_trace->pid);
+ ret = sprintf(buf, "%u\n", bt->pid);
else if (attr == &dev_attr_start_lba)
- ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
+ ret = sprintf(buf, "%llu\n", bt->start_lba);
else if (attr == &dev_attr_end_lba)
- ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
+ ret = sprintf(buf, "%llu\n", bt->end_lba);
out_unlock_bdev:
mutex_unlock(&q->blk_trace_mutex);
@@ -1801,6 +1850,7 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
struct block_device *bdev;
struct request_queue *q;
struct hd_struct *p;
+ struct blk_trace *bt;
u64 value;
ssize_t ret = -EINVAL;
@@ -1831,8 +1881,10 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
mutex_lock(&q->blk_trace_mutex);
+ bt = rcu_dereference_protected(q->blk_trace,
+ lockdep_is_held(&q->blk_trace_mutex));
if (attr == &dev_attr_enable) {
- if (!!value == !!q->blk_trace) {
+ if (!!value == !!bt) {
ret = 0;
goto out_unlock_bdev;
}
@@ -1844,18 +1896,18 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
}
ret = 0;
- if (q->blk_trace == NULL)
+ if (bt == NULL)
ret = blk_trace_setup_queue(q, bdev);
if (ret == 0) {
if (attr == &dev_attr_act_mask)
- q->blk_trace->act_mask = value;
+ bt->act_mask = value;
else if (attr == &dev_attr_pid)
- q->blk_trace->pid = value;
+ bt->pid = value;
else if (attr == &dev_attr_start_lba)
- q->blk_trace->start_lba = value;
+ bt->start_lba = value;
else if (attr == &dev_attr_end_lba)
- q->blk_trace->end_lba = value;
+ bt->end_lba = value;
}
out_unlock_bdev:

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