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Diffstat (limited to 'kernel/trace/blktrace.c')
-rw-r--r--kernel/trace/blktrace.c86
1 files changed, 55 insertions, 31 deletions
diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c
index 5ef0484513ec..7ba62d68885a 100644
--- a/kernel/trace/blktrace.c
+++ b/kernel/trace/blktrace.c
@@ -348,7 +348,7 @@ static int __blk_trace_remove(struct request_queue *q)
struct blk_trace *bt;
bt = rcu_replace_pointer(q->blk_trace, NULL,
- lockdep_is_held(&q->blk_trace_mutex));
+ lockdep_is_held(&q->debugfs_mutex));
if (!bt)
return -EINVAL;
@@ -362,9 +362,9 @@ int blk_trace_remove(struct request_queue *q)
{
int ret;
- mutex_lock(&q->blk_trace_mutex);
+ mutex_lock(&q->debugfs_mutex);
ret = __blk_trace_remove(q);
- mutex_unlock(&q->blk_trace_mutex);
+ mutex_unlock(&q->debugfs_mutex);
return ret;
}
@@ -483,12 +483,11 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
struct dentry *dir = NULL;
int ret;
+ lockdep_assert_held(&q->debugfs_mutex);
+
if (!buts->buf_size || !buts->buf_nr)
return -EINVAL;
- if (!blk_debugfs_root)
- return -ENOENT;
-
strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
@@ -503,7 +502,7 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
* we can be.
*/
if (rcu_dereference_protected(q->blk_trace,
- lockdep_is_held(&q->blk_trace_mutex))) {
+ lockdep_is_held(&q->debugfs_mutex))) {
pr_warn("Concurrent blktraces are not allowed on %s\n",
buts->name);
return -EBUSY;
@@ -522,12 +521,29 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
if (!bt->msg_data)
goto err;
- ret = -ENOENT;
-
- dir = debugfs_lookup(buts->name, blk_debugfs_root);
- if (!dir)
+ /*
+ * When tracing the whole disk reuse the existing debugfs directory
+ * created by the block layer on init. For partitions block devices,
+ * and scsi-generic block devices we create a temporary new debugfs
+ * directory that will be removed once the trace ends.
+ */
+ if (bdev && bdev == bdev->bd_contains)
+ dir = q->debugfs_dir;
+ else
bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);
+ /*
+ * As blktrace relies on debugfs for its interface the debugfs directory
+ * is required, contrary to the usual mantra of not checking for debugfs
+ * files or directories.
+ */
+ if (IS_ERR_OR_NULL(dir)) {
+ pr_warn("debugfs_dir not present for %s so skipping\n",
+ buts->name);
+ ret = -ENOENT;
+ goto err;
+ }
+
bt->dev = dev;
atomic_set(&bt->dropped, 0);
INIT_LIST_HEAD(&bt->running_list);
@@ -563,8 +579,6 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
ret = 0;
err:
- if (dir && !bt->dir)
- dput(dir);
if (ret)
blk_trace_free(bt);
return ret;
@@ -597,9 +611,9 @@ int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
{
int ret;
- mutex_lock(&q->blk_trace_mutex);
+ mutex_lock(&q->debugfs_mutex);
ret = __blk_trace_setup(q, name, dev, bdev, arg);
- mutex_unlock(&q->blk_trace_mutex);
+ mutex_unlock(&q->debugfs_mutex);
return ret;
}
@@ -645,7 +659,7 @@ static int __blk_trace_startstop(struct request_queue *q, int start)
struct blk_trace *bt;
bt = rcu_dereference_protected(q->blk_trace,
- lockdep_is_held(&q->blk_trace_mutex));
+ lockdep_is_held(&q->debugfs_mutex));
if (bt == NULL)
return -EINVAL;
@@ -685,9 +699,9 @@ int blk_trace_startstop(struct request_queue *q, int start)
{
int ret;
- mutex_lock(&q->blk_trace_mutex);
+ mutex_lock(&q->debugfs_mutex);
ret = __blk_trace_startstop(q, start);
- mutex_unlock(&q->blk_trace_mutex);
+ mutex_unlock(&q->debugfs_mutex);
return ret;
}
@@ -716,7 +730,7 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
if (!q)
return -ENXIO;
- mutex_lock(&q->blk_trace_mutex);
+ mutex_lock(&q->debugfs_mutex);
switch (cmd) {
case BLKTRACESETUP:
@@ -743,7 +757,7 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
break;
}
- mutex_unlock(&q->blk_trace_mutex);
+ mutex_unlock(&q->debugfs_mutex);
return ret;
}
@@ -754,14 +768,14 @@ 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);
+ mutex_lock(&q->debugfs_mutex);
if (rcu_dereference_protected(q->blk_trace,
- lockdep_is_held(&q->blk_trace_mutex))) {
+ lockdep_is_held(&q->debugfs_mutex))) {
__blk_trace_startstop(q, 0);
__blk_trace_remove(q);
}
- mutex_unlock(&q->blk_trace_mutex);
+ mutex_unlock(&q->debugfs_mutex);
}
#ifdef CONFIG_BLK_CGROUP
@@ -846,6 +860,13 @@ static void blk_add_trace_rq_issue(void *ignore,
blk_trace_request_get_cgid(q, rq));
}
+static void blk_add_trace_rq_merge(void *ignore,
+ struct request_queue *q, struct request *rq)
+{
+ blk_add_trace_rq(rq, 0, blk_rq_bytes(rq), BLK_TA_BACKMERGE,
+ blk_trace_request_get_cgid(q, rq));
+}
+
static void blk_add_trace_rq_requeue(void *ignore,
struct request_queue *q,
struct request *rq)
@@ -1130,6 +1151,8 @@ static void blk_register_tracepoints(void)
WARN_ON(ret);
ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
WARN_ON(ret);
+ ret = register_trace_block_rq_merge(blk_add_trace_rq_merge, NULL);
+ WARN_ON(ret);
ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
WARN_ON(ret);
ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
@@ -1176,6 +1199,7 @@ static void blk_unregister_tracepoints(void)
unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
+ unregister_trace_block_rq_merge(blk_add_trace_rq_merge, NULL);
unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
@@ -1642,7 +1666,7 @@ static int blk_trace_remove_queue(struct request_queue *q)
struct blk_trace *bt;
bt = rcu_replace_pointer(q->blk_trace, NULL,
- lockdep_is_held(&q->blk_trace_mutex));
+ lockdep_is_held(&q->debugfs_mutex));
if (bt == NULL)
return -EINVAL;
@@ -1817,10 +1841,10 @@ static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
if (q == NULL)
goto out_bdput;
- mutex_lock(&q->blk_trace_mutex);
+ mutex_lock(&q->debugfs_mutex);
bt = rcu_dereference_protected(q->blk_trace,
- lockdep_is_held(&q->blk_trace_mutex));
+ lockdep_is_held(&q->debugfs_mutex));
if (attr == &dev_attr_enable) {
ret = sprintf(buf, "%u\n", !!bt);
goto out_unlock_bdev;
@@ -1838,7 +1862,7 @@ static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
ret = sprintf(buf, "%llu\n", bt->end_lba);
out_unlock_bdev:
- mutex_unlock(&q->blk_trace_mutex);
+ mutex_unlock(&q->debugfs_mutex);
out_bdput:
bdput(bdev);
out:
@@ -1881,10 +1905,10 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
if (q == NULL)
goto out_bdput;
- mutex_lock(&q->blk_trace_mutex);
+ mutex_lock(&q->debugfs_mutex);
bt = rcu_dereference_protected(q->blk_trace,
- lockdep_is_held(&q->blk_trace_mutex));
+ lockdep_is_held(&q->debugfs_mutex));
if (attr == &dev_attr_enable) {
if (!!value == !!bt) {
ret = 0;
@@ -1901,7 +1925,7 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
if (bt == NULL) {
ret = blk_trace_setup_queue(q, bdev);
bt = rcu_dereference_protected(q->blk_trace,
- lockdep_is_held(&q->blk_trace_mutex));
+ lockdep_is_held(&q->debugfs_mutex));
}
if (ret == 0) {
@@ -1916,7 +1940,7 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
}
out_unlock_bdev:
- mutex_unlock(&q->blk_trace_mutex);
+ mutex_unlock(&q->debugfs_mutex);
out_bdput:
bdput(bdev);
out:
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-16 10:05:24 +0000