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-rw-r--r--include/linux/blkdev.h2
-rw-r--r--include/linux/blktrace_api.h18
-rw-r--r--kernel/trace/blktrace.c114
3 files changed, 97 insertions, 37 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 51ccb4b8770a..bff1def62eed 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -531,7 +531,7 @@ 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 2d6e93ab0478..4b2ad374167b 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -336,6 +336,7 @@ static void put_probe_ref(void)
static void blk_trace_cleanup(struct blk_trace *bt)
{
+ synchronize_rcu();
blk_trace_free(bt);
put_probe_ref();
}
@@ -630,8 +631,10 @@ 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;
@@ -741,8 +744,8 @@ 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);
}
@@ -754,8 +757,10 @@ void blk_trace_shutdown(struct request_queue *q)
static union kernfs_node_id *
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 NULL;
@@ -800,10 +805,14 @@ static void blk_add_trace_rq(struct request *rq, int error,
unsigned int nr_bytes, u32 what,
union kernfs_node_id *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);
@@ -812,6 +821,7 @@ 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,
@@ -857,14 +867,19 @@ 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,
@@ -909,11 +924,14 @@ 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, NULL);
+ rcu_read_unlock();
}
}
@@ -925,27 +943,35 @@ 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, NULL);
+ 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, NULL);
+ 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;
@@ -957,14 +983,17 @@ 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, NULL);
}
+ 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);
@@ -973,6 +1002,7 @@ 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();
}
/**
@@ -992,11 +1022,15 @@ 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));
@@ -1005,6 +1039,7 @@ 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();
}
/**
@@ -1025,11 +1060,15 @@ 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));
@@ -1038,6 +1077,7 @@ 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();
}
/**
@@ -1055,14 +1095,19 @@ 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);
@@ -1589,6 +1634,7 @@ static int blk_trace_remove_queue(struct request_queue *q)
return -EINVAL;
put_probe_ref();
+ synchronize_rcu();
blk_trace_free(bt);
return 0;
}
@@ -1750,6 +1796,7 @@ 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));
@@ -1762,21 +1809,23 @@ 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);
@@ -1793,6 +1842,7 @@ 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;
@@ -1823,8 +1873,10 @@ 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;
}
@@ -1836,18 +1888,18 @@ 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:
generated by cgit 1.2.3-korg (git 2.39.0) at 2024-04-16 20:01:14 +0000