block: create the request_queue debugfs_dir on registration
We were only creating the request_queue debugfs_dir only for make_request block drivers (multiqueue), but never for request-based block drivers. We did this as we were only creating non-blktrace additional debugfs files on that directory for make_request drivers. However, since blktrace *always* creates that directory anyway, we special-case the use of that directory on blktrace. Other than this being an eye-sore, this exposes request-based block drivers to the same debugfs fragile race that used to exist with make_request block drivers where if we start adding files onto that directory we can later run a race with a double removal of dentries on the directory if we don't deal with this carefully on blktrace. Instead, just simplify things by always creating the request_queue debugfs_dir on request_queue registration. Rename the mutex also to reflect the fact that this is used outside of the blktrace context. Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
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Коммит
85e0cbbb8a
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@ -51,9 +51,7 @@
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#include "blk-pm.h"
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#include "blk-rq-qos.h"
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#ifdef CONFIG_DEBUG_FS
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struct dentry *blk_debugfs_root;
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#endif
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EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);
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EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
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@ -555,9 +553,7 @@ struct request_queue *__blk_alloc_queue(int node_id)
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kobject_init(&q->kobj, &blk_queue_ktype);
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#ifdef CONFIG_BLK_DEV_IO_TRACE
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mutex_init(&q->blk_trace_mutex);
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#endif
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mutex_init(&q->debugfs_mutex);
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mutex_init(&q->sysfs_lock);
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mutex_init(&q->sysfs_dir_lock);
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spin_lock_init(&q->queue_lock);
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@ -1931,9 +1927,7 @@ int __init blk_dev_init(void)
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blk_requestq_cachep = kmem_cache_create("request_queue",
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sizeof(struct request_queue), 0, SLAB_PANIC, NULL);
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#ifdef CONFIG_DEBUG_FS
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blk_debugfs_root = debugfs_create_dir("block", NULL);
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#endif
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return 0;
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}
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@ -824,9 +824,6 @@ void blk_mq_debugfs_register(struct request_queue *q)
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struct blk_mq_hw_ctx *hctx;
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int i;
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q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent),
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blk_debugfs_root);
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debugfs_create_files(q->debugfs_dir, q, blk_mq_debugfs_queue_attrs);
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/*
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@ -857,9 +854,7 @@ void blk_mq_debugfs_register(struct request_queue *q)
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void blk_mq_debugfs_unregister(struct request_queue *q)
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{
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debugfs_remove_recursive(q->debugfs_dir);
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q->sched_debugfs_dir = NULL;
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q->debugfs_dir = NULL;
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}
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static void blk_mq_debugfs_register_ctx(struct blk_mq_hw_ctx *hctx,
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@ -11,6 +11,7 @@
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#include <linux/blktrace_api.h>
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#include <linux/blk-mq.h>
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#include <linux/blk-cgroup.h>
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#include <linux/debugfs.h>
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#include "blk.h"
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#include "blk-mq.h"
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@ -917,6 +918,9 @@ static void blk_release_queue(struct kobject *kobj)
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blk_mq_release(q);
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blk_trace_shutdown(q);
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mutex_lock(&q->debugfs_mutex);
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debugfs_remove_recursive(q->debugfs_dir);
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mutex_unlock(&q->debugfs_mutex);
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if (queue_is_mq(q))
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blk_mq_debugfs_unregister(q);
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@ -989,6 +993,11 @@ int blk_register_queue(struct gendisk *disk)
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goto unlock;
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}
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mutex_lock(&q->debugfs_mutex);
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q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent),
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blk_debugfs_root);
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mutex_unlock(&q->debugfs_mutex);
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if (queue_is_mq(q)) {
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__blk_mq_register_dev(dev, q);
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blk_mq_debugfs_register(q);
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@ -14,9 +14,7 @@
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/* Max future timer expiry for timeouts */
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#define BLK_MAX_TIMEOUT (5 * HZ)
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#ifdef CONFIG_DEBUG_FS
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extern struct dentry *blk_debugfs_root;
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#endif
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struct blk_flush_queue {
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unsigned int flush_pending_idx:1;
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@ -528,9 +528,9 @@ struct request_queue {
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unsigned int sg_timeout;
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unsigned int sg_reserved_size;
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int node;
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struct mutex debugfs_mutex;
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#ifdef CONFIG_BLK_DEV_IO_TRACE
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struct blk_trace __rcu *blk_trace;
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struct mutex blk_trace_mutex;
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#endif
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/*
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* for flush operations
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@ -574,8 +574,9 @@ struct request_queue {
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struct list_head tag_set_list;
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struct bio_set bio_split;
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#ifdef CONFIG_BLK_DEBUG_FS
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struct dentry *debugfs_dir;
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#ifdef CONFIG_BLK_DEBUG_FS
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struct dentry *sched_debugfs_dir;
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struct dentry *rqos_debugfs_dir;
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#endif
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@ -348,7 +348,7 @@ static int __blk_trace_remove(struct request_queue *q)
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struct blk_trace *bt;
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bt = rcu_replace_pointer(q->blk_trace, NULL,
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lockdep_is_held(&q->blk_trace_mutex));
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lockdep_is_held(&q->debugfs_mutex));
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if (!bt)
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return -EINVAL;
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@ -362,9 +362,9 @@ int blk_trace_remove(struct request_queue *q)
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{
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int ret;
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mutex_lock(&q->blk_trace_mutex);
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mutex_lock(&q->debugfs_mutex);
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ret = __blk_trace_remove(q);
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mutex_unlock(&q->blk_trace_mutex);
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mutex_unlock(&q->debugfs_mutex);
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return ret;
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}
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@ -483,14 +483,11 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
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struct dentry *dir = NULL;
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int ret;
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lockdep_assert_held(&q->blk_trace_mutex);
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lockdep_assert_held(&q->debugfs_mutex);
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if (!buts->buf_size || !buts->buf_nr)
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return -EINVAL;
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if (!blk_debugfs_root)
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return -ENOENT;
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strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
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buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
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@ -505,7 +502,7 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
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* we can be.
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*/
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if (rcu_dereference_protected(q->blk_trace,
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lockdep_is_held(&q->blk_trace_mutex))) {
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lockdep_is_held(&q->debugfs_mutex))) {
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pr_warn("Concurrent blktraces are not allowed on %s\n",
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buts->name);
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return -EBUSY;
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@ -524,18 +521,15 @@ static int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
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if (!bt->msg_data)
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goto err;
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#ifdef CONFIG_BLK_DEBUG_FS
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/*
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* When tracing whole make_request drivers (multiqueue) block devices,
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* reuse the existing debugfs directory created by the block layer on
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* init. For request-based block devices, all partitions block devices,
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* When tracing the whole disk reuse the existing debugfs directory
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* created by the block layer on init. For partitions block devices,
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* and scsi-generic block devices we create a temporary new debugfs
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* directory that will be removed once the trace ends.
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*/
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if (queue_is_mq(q) && bdev && bdev == bdev->bd_contains)
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if (bdev && bdev == bdev->bd_contains)
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dir = q->debugfs_dir;
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else
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#endif
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bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);
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/*
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@ -617,9 +611,9 @@ int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
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{
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int ret;
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mutex_lock(&q->blk_trace_mutex);
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mutex_lock(&q->debugfs_mutex);
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ret = __blk_trace_setup(q, name, dev, bdev, arg);
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mutex_unlock(&q->blk_trace_mutex);
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mutex_unlock(&q->debugfs_mutex);
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return ret;
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}
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@ -665,7 +659,7 @@ static int __blk_trace_startstop(struct request_queue *q, int start)
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struct blk_trace *bt;
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bt = rcu_dereference_protected(q->blk_trace,
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lockdep_is_held(&q->blk_trace_mutex));
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lockdep_is_held(&q->debugfs_mutex));
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if (bt == NULL)
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return -EINVAL;
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@ -705,9 +699,9 @@ int blk_trace_startstop(struct request_queue *q, int start)
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{
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int ret;
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mutex_lock(&q->blk_trace_mutex);
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mutex_lock(&q->debugfs_mutex);
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ret = __blk_trace_startstop(q, start);
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mutex_unlock(&q->blk_trace_mutex);
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mutex_unlock(&q->debugfs_mutex);
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return ret;
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}
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@ -736,7 +730,7 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
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if (!q)
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return -ENXIO;
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mutex_lock(&q->blk_trace_mutex);
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mutex_lock(&q->debugfs_mutex);
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switch (cmd) {
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case BLKTRACESETUP:
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@ -763,7 +757,7 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
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break;
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}
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mutex_unlock(&q->blk_trace_mutex);
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mutex_unlock(&q->debugfs_mutex);
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return ret;
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}
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@ -774,14 +768,14 @@ int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
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**/
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void blk_trace_shutdown(struct request_queue *q)
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{
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mutex_lock(&q->blk_trace_mutex);
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mutex_lock(&q->debugfs_mutex);
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if (rcu_dereference_protected(q->blk_trace,
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lockdep_is_held(&q->blk_trace_mutex))) {
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lockdep_is_held(&q->debugfs_mutex))) {
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__blk_trace_startstop(q, 0);
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__blk_trace_remove(q);
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}
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mutex_unlock(&q->blk_trace_mutex);
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mutex_unlock(&q->debugfs_mutex);
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}
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#ifdef CONFIG_BLK_CGROUP
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@ -1662,7 +1656,7 @@ static int blk_trace_remove_queue(struct request_queue *q)
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struct blk_trace *bt;
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bt = rcu_replace_pointer(q->blk_trace, NULL,
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lockdep_is_held(&q->blk_trace_mutex));
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lockdep_is_held(&q->debugfs_mutex));
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if (bt == NULL)
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return -EINVAL;
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@ -1837,10 +1831,10 @@ static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
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if (q == NULL)
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goto out_bdput;
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mutex_lock(&q->blk_trace_mutex);
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mutex_lock(&q->debugfs_mutex);
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bt = rcu_dereference_protected(q->blk_trace,
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lockdep_is_held(&q->blk_trace_mutex));
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lockdep_is_held(&q->debugfs_mutex));
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if (attr == &dev_attr_enable) {
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ret = sprintf(buf, "%u\n", !!bt);
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goto out_unlock_bdev;
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@ -1858,7 +1852,7 @@ static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
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ret = sprintf(buf, "%llu\n", bt->end_lba);
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out_unlock_bdev:
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mutex_unlock(&q->blk_trace_mutex);
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mutex_unlock(&q->debugfs_mutex);
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out_bdput:
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bdput(bdev);
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out:
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@ -1901,10 +1895,10 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
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if (q == NULL)
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goto out_bdput;
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mutex_lock(&q->blk_trace_mutex);
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mutex_lock(&q->debugfs_mutex);
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bt = rcu_dereference_protected(q->blk_trace,
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lockdep_is_held(&q->blk_trace_mutex));
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lockdep_is_held(&q->debugfs_mutex));
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if (attr == &dev_attr_enable) {
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if (!!value == !!bt) {
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ret = 0;
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@ -1921,7 +1915,7 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
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if (bt == NULL) {
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ret = blk_trace_setup_queue(q, bdev);
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bt = rcu_dereference_protected(q->blk_trace,
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lockdep_is_held(&q->blk_trace_mutex));
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lockdep_is_held(&q->debugfs_mutex));
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}
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if (ret == 0) {
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@ -1936,7 +1930,7 @@ static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
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}
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out_unlock_bdev:
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mutex_unlock(&q->blk_trace_mutex);
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mutex_unlock(&q->debugfs_mutex);
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out_bdput:
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bdput(bdev);
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out:
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