Merge tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linuxgrafted

Pull I3C updates from Alexandre Belloni:
 "A new driver this cycle, for the AMD AXI I3C controller.

  There are also new features such as IBI wakeup support, SETAASA device
  discovery and ACPI support for the the DAA methods, meaning we can now
  communicate with the SPD devices on DDR5 modules.

  New driver:
   - AMD AXI I3C master controller

  Subsystem:
   - I3C Common Command Code (CCC) handling improvements, especially
     around GET CCCs
   - SETAASA device discovery support
   - ACPI support for all existing DAA methods like SETDASA, SETNEWDA as
     well as I2C devices on I3C bus
   - IBI-based wakeup support

  Drivers:
   - dw: SETAASA support
   - mipi-i3c-hci: advertise IBI wakeup capability, AMD_PT I3C
     controller support, PIO queue management support for HCI v1.2
   - renesas: improve suspend to RAM support, add runtime PM support"

* tag 'i3c/for-7.3' of git://git.kernel.org/pub/scm/linux/kernel/git/i3c/linux: (70 commits)
  i3c: dw: reduce do_daa time if there's no client
  i3c: mipi-i3c-hci: Add support for AMD_PT I3C controller
  i3c: mipi-i3c-hci: Add PIO queue management support for HCI v1.2
  i3c: mipi-i3c-hci: Fix missing STAT_IBI_STATUS_THLD in PIO mode
  i3c: dw: rename "pclk" to "apb" to match dt-binding
  i3c: dw: make struct dw_i3c_cmd smaller
  i3c: dw: use COMMAND_PORT_TRANSFER_ARG instead of hardcoding
  i3c: renesas: Don't register devices when ENTDAA times out
  i3c: master: dw-i3c-master: fix OD timing for first broadcast
  i3c: mipi-i3c-hci: Advertise IBI wakeup capability
  i3c: mipi-i3c-hci: Factor out i3c_hci_sysdev()
  i3c: mipi-i3c-hci-pci: Propagate I3C wakeup requirements to PCI
  i3c: master: Reject IBI requests from non-IBI-capable devices
  i3c: master: Add helper to query bus wakeup requirements
  i3c: master: Report wakeup events for IBIs
  i3c: master: Support IBI-based wakeup capability
  i3c: master: Fix potential UAF in i3c_device_match()
  i3c: master: Fix potential UAF in i3c_device_uevent()
  i3c: Make dev->desc locking assumptions explicit
  i3c: master: Fix use-after-free of master->this
  ...

1 files changed, 829 insertions, 0 deletions

diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
new file mode 100644
index 000000000..6754d8f94
--- /dev/null
+++ b/block/blk-mq-debugfs.c
@@ -0,0 +1,829 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2017 Facebook
+ */
+
+#include <linux/kernel.h>
+#include <linux/blkdev.h>
+#include <linux/build_bug.h>
+#include <linux/debugfs.h>
+
+#include "blk.h"
+#include "blk-mq.h"
+#include "blk-mq-debugfs.h"
+#include "blk-mq-sched.h"
+#include "blk-rq-qos.h"
+
+static int queue_poll_stat_show(void *data, struct seq_file *m)
+{
+	return 0;
+}
+
+#define TO_REQUEST_QUEUE(m) ((struct request_queue *)m->private)
+
+static void *queue_requeue_list_start(struct seq_file *m, loff_t *pos)
+	__acquires(&TO_REQUEST_QUEUE(m)->requeue_lock)
+{
+	struct request_queue *q = m->private;
+
+	spin_lock_irq(&q->requeue_lock);
+	return seq_list_start(&q->requeue_list, *pos);
+}
+
+static void *queue_requeue_list_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	struct request_queue *q = m->private;
+
+	return seq_list_next(v, &q->requeue_list, pos);
+}
+
+static void queue_requeue_list_stop(struct seq_file *m, void *v)
+	__releases(&TO_REQUEST_QUEUE(m)->requeue_lock)
+{
+	struct request_queue *q = m->private;
+
+	spin_unlock_irq(&q->requeue_lock);
+}
+
+#undef TO_REQUEST_QUEUE
+
+static const struct seq_operations queue_requeue_list_seq_ops = {
+	.start	= queue_requeue_list_start,
+	.next	= queue_requeue_list_next,
+	.stop	= queue_requeue_list_stop,
+	.show	= blk_mq_debugfs_rq_show,
+};
+
+static int blk_flags_show(struct seq_file *m, const unsigned long flags,
+			  const char *const *flag_name, int flag_name_count)
+{
+	bool sep = false;
+	int i;
+
+	for (i = 0; i < sizeof(flags) * BITS_PER_BYTE; i++) {
+		if (!(flags & BIT(i)))
+			continue;
+		if (sep)
+			seq_puts(m, "|");
+		sep = true;
+		if (i < flag_name_count && flag_name[i])
+			seq_puts(m, flag_name[i]);
+		else
+			seq_printf(m, "%d", i);
+	}
+	return 0;
+}
+
+static int queue_pm_only_show(void *data, struct seq_file *m)
+{
+	struct request_queue *q = data;
+
+	seq_printf(m, "%d\n", atomic_read(&q->pm_only));
+	return 0;
+}
+
+#define QUEUE_FLAG_NAME(name) [QUEUE_FLAG_##name] = #name
+static const char *const blk_queue_flag_name[] = {
+	QUEUE_FLAG_NAME(DYING),
+	QUEUE_FLAG_NAME(NOMERGES),
+	QUEUE_FLAG_NAME(SAME_COMP),
+	QUEUE_FLAG_NAME(FAIL_IO),
+	QUEUE_FLAG_NAME(NOXMERGES),
+	QUEUE_FLAG_NAME(SAME_FORCE),
+	QUEUE_FLAG_NAME(INIT_DONE),
+	QUEUE_FLAG_NAME(STATS),
+	QUEUE_FLAG_NAME(REGISTERED),
+	QUEUE_FLAG_NAME(QUIESCED),
+	QUEUE_FLAG_NAME(RQ_ALLOC_TIME),
+	QUEUE_FLAG_NAME(HCTX_ACTIVE),
+	QUEUE_FLAG_NAME(SQ_SCHED),
+	QUEUE_FLAG_NAME(DISABLE_WBT_DEF),
+	QUEUE_FLAG_NAME(NO_ELV_SWITCH),
+	QUEUE_FLAG_NAME(QOS_ENABLED),
+	QUEUE_FLAG_NAME(BIO_ISSUE_TIME),
+	QUEUE_FLAG_NAME(ZONED_QD1_WRITES),
+};
+#undef QUEUE_FLAG_NAME
+
+static int queue_state_show(void *data, struct seq_file *m)
+{
+	struct request_queue *q = data;
+
+	BUILD_BUG_ON(ARRAY_SIZE(blk_queue_flag_name) != QUEUE_FLAG_MAX);
+	blk_flags_show(m, q->queue_flags, blk_queue_flag_name,
+		       ARRAY_SIZE(blk_queue_flag_name));
+	seq_puts(m, "\n");
+	return 0;
+}
+
+static ssize_t queue_state_write(void *data, const char __user *buf,
+				 size_t count, loff_t *ppos)
+{
+	struct request_queue *q = data;
+	char opbuf[16] = { }, *op;
+
+	/*
+	 * The "state" attribute is removed when the queue is removed.  Don't
+	 * allow setting the state on a dying queue to avoid a use-after-free.
+	 */
+	if (blk_queue_dying(q))
+		return -ENOENT;
+
+	if (count >= sizeof(opbuf)) {
+		pr_err("%s: operation too long\n", __func__);
+		goto inval;
+	}
+
+	if (copy_from_user(opbuf, buf, count))
+		return -EFAULT;
+	op = strstrip(opbuf);
+	if (strcmp(op, "run") == 0) {
+		blk_mq_run_hw_queues(q, true);
+	} else if (strcmp(op, "start") == 0) {
+		blk_mq_start_stopped_hw_queues(q, true);
+	} else if (strcmp(op, "kick") == 0) {
+		blk_mq_kick_requeue_list(q);
+	} else {
+		pr_err("%s: unsupported operation '%s'\n", __func__, op);
+inval:
+		pr_err("%s: use 'run', 'start' or 'kick'\n", __func__);
+		return -EINVAL;
+	}
+	return count;
+}
+
+static const struct blk_mq_debugfs_attr blk_mq_debugfs_queue_attrs[] = {
+	{ "poll_stat", 0400, queue_poll_stat_show },
+	{ "requeue_list", 0400, .seq_ops = &queue_requeue_list_seq_ops },
+	{ "pm_only", 0600, queue_pm_only_show, NULL },
+	{ "state", 0600, queue_state_show, queue_state_write },
+	{ "zone_wplugs", 0400, queue_zone_wplugs_show, NULL },
+	{ },
+};
+
+#define HCTX_STATE_NAME(name) [BLK_MQ_S_##name] = #name
+static const char *const hctx_state_name[] = {
+	HCTX_STATE_NAME(STOPPED),
+	HCTX_STATE_NAME(TAG_ACTIVE),
+	HCTX_STATE_NAME(SCHED_RESTART),
+	HCTX_STATE_NAME(INACTIVE),
+};
+#undef HCTX_STATE_NAME
+
+static int hctx_state_show(void *data, struct seq_file *m)
+{
+	struct blk_mq_hw_ctx *hctx = data;
+
+	BUILD_BUG_ON(ARRAY_SIZE(hctx_state_name) != BLK_MQ_S_MAX);
+	blk_flags_show(m, hctx->state, hctx_state_name,
+		       ARRAY_SIZE(hctx_state_name));
+	seq_puts(m, "\n");
+	return 0;
+}
+
+#define HCTX_FLAG_NAME(name) [ilog2(BLK_MQ_F_##name)] = #name
+static const char *const hctx_flag_name[] = {
+	HCTX_FLAG_NAME(TAG_QUEUE_SHARED),
+	HCTX_FLAG_NAME(STACKING),
+	HCTX_FLAG_NAME(TAG_HCTX_SHARED),
+	HCTX_FLAG_NAME(BLOCKING),
+	HCTX_FLAG_NAME(TAG_RR),
+	HCTX_FLAG_NAME(NO_SCHED_BY_DEFAULT),
+};
+#undef HCTX_FLAG_NAME
+
+static int hctx_flags_show(void *data, struct seq_file *m)
+{
+	struct blk_mq_hw_ctx *hctx = data;
+
+	BUILD_BUG_ON(ARRAY_SIZE(hctx_flag_name) != ilog2(BLK_MQ_F_MAX));
+
+	blk_flags_show(m, hctx->flags, hctx_flag_name,
+			ARRAY_SIZE(hctx_flag_name));
+	seq_puts(m, "\n");
+	return 0;
+}
+
+#define CMD_FLAG_NAME(name) [__REQ_##name] = #name
+static const char *const cmd_flag_name[] = {
+	CMD_FLAG_NAME(FAILFAST_DEV),
+	CMD_FLAG_NAME(FAILFAST_TRANSPORT),
+	CMD_FLAG_NAME(FAILFAST_DRIVER),
+	CMD_FLAG_NAME(SYNC),
+	CMD_FLAG_NAME(META),
+	CMD_FLAG_NAME(PRIO),
+	CMD_FLAG_NAME(NOMERGE),
+	CMD_FLAG_NAME(IDLE),
+	CMD_FLAG_NAME(INTEGRITY),
+	CMD_FLAG_NAME(FUA),
+	CMD_FLAG_NAME(PREFLUSH),
+	CMD_FLAG_NAME(RAHEAD),
+	CMD_FLAG_NAME(BACKGROUND),
+	CMD_FLAG_NAME(NOWAIT),
+	CMD_FLAG_NAME(POLLED),
+	CMD_FLAG_NAME(ALLOC_CACHE),
+	CMD_FLAG_NAME(SWAP),
+	CMD_FLAG_NAME(DRV),
+	CMD_FLAG_NAME(FS_PRIVATE),
+	CMD_FLAG_NAME(ATOMIC),
+	CMD_FLAG_NAME(NOUNMAP),
+};
+#undef CMD_FLAG_NAME
+
+#define RQF_NAME(name) [__RQF_##name] = #name
+static const char *const rqf_name[] = {
+	RQF_NAME(STARTED),
+	RQF_NAME(FLUSH_SEQ),
+	RQF_NAME(MIXED_MERGE),
+	RQF_NAME(DONTPREP),
+	RQF_NAME(SCHED_TAGS),
+	RQF_NAME(USE_SCHED),
+	RQF_NAME(FAILED),
+	RQF_NAME(QUIET),
+	RQF_NAME(IO_STAT),
+	RQF_NAME(PM),
+	RQF_NAME(HASHED),
+	RQF_NAME(STATS),
+	RQF_NAME(SPECIAL_PAYLOAD),
+	RQF_NAME(ZONE_WRITE_PLUGGING),
+	RQF_NAME(TIMED_OUT),
+	RQF_NAME(RESV),
+};
+#undef RQF_NAME
+
+static const char *const blk_mq_rq_state_name_array[] = {
+	[MQ_RQ_IDLE]		= "idle",
+	[MQ_RQ_IN_FLIGHT]	= "in_flight",
+	[MQ_RQ_COMPLETE]	= "complete",
+};
+
+static const char *blk_mq_rq_state_name(enum mq_rq_state rq_state)
+{
+	if (WARN_ON_ONCE((unsigned int)rq_state >=
+			 ARRAY_SIZE(blk_mq_rq_state_name_array)))
+		return "(?)";
+	return blk_mq_rq_state_name_array[rq_state];
+}
+
+int __blk_mq_debugfs_rq_show(struct seq_file *m, struct request *rq)
+{
+	const struct blk_mq_ops *const mq_ops = rq->q->mq_ops;
+	const enum req_op op = req_op(rq);
+	const char *op_str = blk_op_str(op);
+
+	BUILD_BUG_ON(ARRAY_SIZE(cmd_flag_name) != __REQ_NR_BITS);
+	BUILD_BUG_ON(ARRAY_SIZE(rqf_name) != __RQF_BITS);
+
+	seq_printf(m, "%p {.op=", rq);
+	if (strcmp(op_str, "UNKNOWN") == 0)
+		seq_printf(m, "%u", op);
+	else
+		seq_printf(m, "%s", op_str);
+	seq_puts(m, ", .cmd_flags=");
+	blk_flags_show(m, (__force unsigned int)(rq->cmd_flags & ~REQ_OP_MASK),
+		       cmd_flag_name, ARRAY_SIZE(cmd_flag_name));
+	seq_puts(m, ", .rq_flags=");
+	blk_flags_show(m, (__force unsigned int)rq->rq_flags, rqf_name,
+		       ARRAY_SIZE(rqf_name));
+	seq_printf(m, ", .state=%s", blk_mq_rq_state_name(blk_mq_rq_state(rq)));
+	seq_printf(m, ", .tag=%d, .internal_tag=%d", rq->tag,
+		   rq->internal_tag);
+	if (mq_ops->show_rq)
+		mq_ops->show_rq(m, rq);
+	seq_puts(m, "}\n");
+	return 0;
+}
+EXPORT_SYMBOL_GPL(__blk_mq_debugfs_rq_show);
+
+int blk_mq_debugfs_rq_show(struct seq_file *m, void *v)
+{
+	return __blk_mq_debugfs_rq_show(m, list_entry_rq(v));
+}
+EXPORT_SYMBOL_GPL(blk_mq_debugfs_rq_show);
+
+#define TO_HCTX(m) ((struct blk_mq_hw_ctx *)m->private)
+
+static void *hctx_dispatch_start(struct seq_file *m, loff_t *pos)
+	__acquires(&TO_HCTX(m)->lock)
+{
+	struct blk_mq_hw_ctx *hctx = m->private;
+
+	spin_lock(&hctx->lock);
+	return seq_list_start(&hctx->dispatch, *pos);
+}
+
+static void *hctx_dispatch_next(struct seq_file *m, void *v, loff_t *pos)
+{
+	struct blk_mq_hw_ctx *hctx = m->private;
+
+	return seq_list_next(v, &hctx->dispatch, pos);
+}
+
+static void hctx_dispatch_stop(struct seq_file *m, void *v)
+	__releases(&TO_HCTX(m)->lock)
+{
+	struct blk_mq_hw_ctx *hctx = m->private;
+
+	spin_unlock(&hctx->lock);
+}
+
+#undef TO_HCTX
+
+static const struct seq_operations hctx_dispatch_seq_ops = {
+	.start	= hctx_dispatch_start,
+	.next	= hctx_dispatch_next,
+	.stop	= hctx_dispatch_stop,
+	.show	= blk_mq_debugfs_rq_show,
+};
+
+struct show_busy_params {
+	struct seq_file		*m;
+	struct blk_mq_hw_ctx	*hctx;
+};
+
+/*
+ * Note: the state of a request may change while this function is in progress,
+ * e.g. due to a concurrent blk_mq_finish_request() call. Returns true to
+ * keep iterating requests.
+ */
+static bool hctx_show_busy_rq(struct request *rq, void *data)
+{
+	const struct show_busy_params *params = data;
+
+	if (rq->mq_hctx == params->hctx)
+		__blk_mq_debugfs_rq_show(params->m, rq);
+
+	return true;
+}
+
+static int hctx_busy_show(void *data, struct seq_file *m)
+{
+	struct blk_mq_hw_ctx *hctx = data;
+	struct show_busy_params params = { .m = m, .hctx = hctx };
+	int res;
+
+	res = mutex_lock_interruptible(&hctx->queue->elevator_lock);
+	if (res)
+		return res;
+	blk_mq_tagset_busy_iter(hctx->queue->tag_set, hctx_show_busy_rq,
+				&params);
+	mutex_unlock(&hctx->queue->elevator_lock);
+
+	return 0;
+}
+
+static const char *const hctx_types[] = {
+	[HCTX_TYPE_DEFAULT]	= "default",
+	[HCTX_TYPE_READ]	= "read",
+	[HCTX_TYPE_POLL]	= "poll",
+};
+
+static int hctx_type_show(void *data, struct seq_file *m)
+{
+	struct blk_mq_hw_ctx *hctx = data;
+
+	BUILD_BUG_ON(ARRAY_SIZE(hctx_types) != HCTX_MAX_TYPES);
+	seq_printf(m, "%s\n", hctx_types[hctx->type]);
+	return 0;
+}
+
+static int hctx_ctx_map_show(void *data, struct seq_file *m)
+{
+	struct blk_mq_hw_ctx *hctx = data;
+
+	sbitmap_bitmap_show(&hctx->ctx_map, m);
+	return 0;
+}
+
+static void blk_mq_debugfs_tags_show(struct seq_file *m,
+				     struct blk_mq_tags *tags)
+{
+	seq_printf(m, "nr_tags=%u\n", tags->nr_tags);
+	seq_printf(m, "nr_reserved_tags=%u\n", tags->nr_reserved_tags);
+	seq_printf(m, "active_queues=%d\n",
+		   READ_ONCE(tags->active_queues));
+
+	seq_puts(m, "\nbitmap_tags:\n");
+	sbitmap_queue_show(&tags->bitmap_tags, m);
+
+	if (tags->nr_reserved_tags) {
+		seq_puts(m, "\nbreserved_tags:\n");
+		sbitmap_queue_show(&tags->breserved_tags, m);
+	}
+}
+
+static int hctx_tags_show(void *data, struct seq_file *m)
+{
+	struct blk_mq_hw_ctx *hctx = data;
+	struct request_queue *q = hctx->queue;
+	int res;
+
+	res = mutex_lock_interruptible(&q->elevator_lock);
+	if (res)
+		return res;
+	if (hctx->tags)
+		blk_mq_debugfs_tags_show(m, hctx->tags);
+	mutex_unlock(&q->elevator_lock);
+
+	return 0;
+}
+
+static int hctx_tags_bitmap_show(void *data, struct seq_file *m)
+{
+	struct blk_mq_hw_ctx *hctx = data;
+	struct request_queue *q = hctx->queue;
+	int res;
+
+	res = mutex_lock_interruptible(&q->elevator_lock);
+	if (res)
+		return res;
+	if (hctx->tags)
+		sbitmap_bitmap_show(&hctx->tags->bitmap_tags.sb, m);
+	mutex_unlock(&q->elevator_lock);
+
+	return 0;
+}
+
+static int hctx_sched_tags_show(void *data, struct seq_file *m)
+{
+	struct blk_mq_hw_ctx *hctx = data;
+	struct request_queue *q = hctx->queue;
+	int res;
+
+	res = mutex_lock_interruptible(&q->elevator_lock);
+	if (res)
+		return res;
+	if (hctx->sched_tags)
+		blk_mq_debugfs_tags_show(m, hctx->sched_tags);
+	mutex_unlock(&q->elevator_lock);
+
+	return 0;
+}
+
+static int hctx_sched_tags_bitmap_show(void *data, struct seq_file *m)
+{
+	struct blk_mq_hw_ctx *hctx = data;
+	struct request_queue *q = hctx->queue;
+	int res;
+
+	res = mutex_lock_interruptible(&q->elevator_lock);
+	if (res)
+		return res;
+	if (hctx->sched_tags)
+		sbitmap_bitmap_show(&hctx->sched_tags->bitmap_tags.sb, m);
+	mutex_unlock(&q->elevator_lock);
+
+	return 0;
+}
+
+static int hctx_active_show(void *data, struct seq_file *m)
+{
+	struct blk_mq_hw_ctx *hctx = data;
+
+	seq_printf(m, "%d\n", __blk_mq_active_requests(hctx));
+	return 0;
+}
+
+static int hctx_dispatch_busy_show(void *data, struct seq_file *m)
+{
+	struct blk_mq_hw_ctx *hctx = data;
+
+	seq_printf(m, "%u\n", hctx->dispatch_busy);
+	return 0;
+}
+
+#define TO_CTX(m) ((struct blk_mq_ctx *)m->private)
+
+#define CTX_RQ_SEQ_OPS(name, type)					\
+static void *ctx_##name##_rq_list_start(struct seq_file *m, loff_t *pos) \
+	__acquires(&TO_CTX(m)->lock)					\
+{									\
+	struct blk_mq_ctx *ctx = m->private;				\
+									\
+	spin_lock(&ctx->lock);						\
+	return seq_list_start(&ctx->rq_lists[type], *pos);		\
+}									\
+									\
+static void *ctx_##name##_rq_list_next(struct seq_file *m, void *v,	\
+				     loff_t *pos)			\
+{									\
+	struct blk_mq_ctx *ctx = m->private;				\
+									\
+	return seq_list_next(v, &ctx->rq_lists[type], pos);		\
+}									\
+									\
+static void ctx_##name##_rq_list_stop(struct seq_file *m, void *v)	\
+	__releases(&TO_CTX(m)->lock)					\
+{									\
+	struct blk_mq_ctx *ctx = m->private;				\
+									\
+	spin_unlock(&ctx->lock);					\
+}									\
+									\
+static const struct seq_operations ctx_##name##_rq_list_seq_ops = {	\
+	.start	= ctx_##name##_rq_list_start,				\
+	.next	= ctx_##name##_rq_list_next,				\
+	.stop	= ctx_##name##_rq_list_stop,				\
+	.show	= blk_mq_debugfs_rq_show,				\
+}
+
+CTX_RQ_SEQ_OPS(default, HCTX_TYPE_DEFAULT);
+CTX_RQ_SEQ_OPS(read, HCTX_TYPE_READ);
+CTX_RQ_SEQ_OPS(poll, HCTX_TYPE_POLL);
+
+#undef TO_CTX
+
+static int blk_mq_debugfs_show(struct seq_file *m, void *v)
+{
+	const struct blk_mq_debugfs_attr *attr = m->private;
+	void *data = debugfs_get_aux(m->file);
+
+	return attr->show(data, m);
+}
+
+static ssize_t blk_mq_debugfs_write(struct file *file, const char __user *buf,
+				    size_t count, loff_t *ppos)
+{
+	struct seq_file *m = file->private_data;
+	const struct blk_mq_debugfs_attr *attr = m->private;
+	void *data = debugfs_get_aux(file);
+
+	/*
+	 * Attributes that only implement .seq_ops are read-only and 'attr' is
+	 * the same with 'data' in this case.
+	 */
+	if (attr == data || !attr->write)
+		return -EPERM;
+
+	return attr->write(data, buf, count, ppos);
+}
+
+static int blk_mq_debugfs_open(struct inode *inode, struct file *file)
+{
+	const struct blk_mq_debugfs_attr *attr = inode->i_private;
+	void *data = debugfs_get_aux(file);
+	struct seq_file *m;
+	int ret;
+
+	if (attr->seq_ops) {
+		ret = seq_open(file, attr->seq_ops);
+		if (!ret) {
+			m = file->private_data;
+			m->private = data;
+		}
+		return ret;
+	}
+
+	if (WARN_ON_ONCE(!attr->show))
+		return -EPERM;
+
+	return single_open(file, blk_mq_debugfs_show, inode->i_private);
+}
+
+static int blk_mq_debugfs_release(struct inode *inode, struct file *file)
+{
+	const struct blk_mq_debugfs_attr *attr = inode->i_private;
+
+	if (attr->show)
+		return single_release(inode, file);
+
+	return seq_release(inode, file);
+}
+
+static const struct file_operations blk_mq_debugfs_fops = {
+	.open		= blk_mq_debugfs_open,
+	.read		= seq_read,
+	.write		= blk_mq_debugfs_write,
+	.llseek		= seq_lseek,
+	.release	= blk_mq_debugfs_release,
+};
+
+static const struct blk_mq_debugfs_attr blk_mq_debugfs_hctx_attrs[] = {
+	{"state", 0400, hctx_state_show},
+	{"flags", 0400, hctx_flags_show},
+	{"dispatch", 0400, .seq_ops = &hctx_dispatch_seq_ops},
+	{"busy", 0400, hctx_busy_show},
+	{"ctx_map", 0400, hctx_ctx_map_show},
+	{"tags", 0400, hctx_tags_show},
+	{"tags_bitmap", 0400, hctx_tags_bitmap_show},
+	{"sched_tags", 0400, hctx_sched_tags_show},
+	{"sched_tags_bitmap", 0400, hctx_sched_tags_bitmap_show},
+	{"active", 0400, hctx_active_show},
+	{"dispatch_busy", 0400, hctx_dispatch_busy_show},
+	{"type", 0400, hctx_type_show},
+	{},
+};
+
+static const struct blk_mq_debugfs_attr blk_mq_debugfs_ctx_attrs[] = {
+	{"default_rq_list", 0400, .seq_ops = &ctx_default_rq_list_seq_ops},
+	{"read_rq_list", 0400, .seq_ops = &ctx_read_rq_list_seq_ops},
+	{"poll_rq_list", 0400, .seq_ops = &ctx_poll_rq_list_seq_ops},
+	{},
+};
+
+static void debugfs_create_files(struct request_queue *q, struct dentry *parent,
+				 void *data,
+				 const struct blk_mq_debugfs_attr *attr)
+{
+	lockdep_assert_held(&q->debugfs_mutex);
+	/*
+	 * debugfs_mutex should not be nested under other locks that can be
+	 * grabbed while queue is frozen.
+	 */
+	lockdep_assert_not_held(&q->elevator_lock);
+	lockdep_assert_not_held(&q->rq_qos_mutex);
+
+	if (IS_ERR_OR_NULL(parent))
+		return;
+
+	for (; attr->name; attr++)
+		debugfs_create_file_aux(attr->name, attr->mode, parent,
+				    (void *)attr, data, &blk_mq_debugfs_fops);
+}
+
+void blk_mq_debugfs_register(struct request_queue *q)
+{
+	struct blk_mq_hw_ctx *hctx;
+	unsigned long i;
+
+	debugfs_create_files(q, q->debugfs_dir, q, blk_mq_debugfs_queue_attrs);
+
+	queue_for_each_hw_ctx(q, hctx, i) {
+		if (!hctx->debugfs_dir)
+			blk_mq_debugfs_register_hctx(q, hctx);
+	}
+
+	blk_mq_debugfs_register_rq_qos(q);
+}
+
+static void blk_mq_debugfs_register_ctx(struct blk_mq_hw_ctx *hctx,
+					struct blk_mq_ctx *ctx)
+{
+	struct dentry *ctx_dir;
+	char name[20];
+
+	snprintf(name, sizeof(name), "cpu%u", ctx->cpu);
+	ctx_dir = debugfs_create_dir(name, hctx->debugfs_dir);
+
+	debugfs_create_files(hctx->queue, ctx_dir, ctx,
+			     blk_mq_debugfs_ctx_attrs);
+}
+
+void blk_mq_debugfs_register_hctx(struct request_queue *q,
+				  struct blk_mq_hw_ctx *hctx)
+{
+	struct blk_mq_ctx *ctx;
+	char name[20];
+	int i;
+
+	if (!q->debugfs_dir)
+		return;
+
+	snprintf(name, sizeof(name), "hctx%u", hctx->queue_num);
+	hctx->debugfs_dir = debugfs_create_dir(name, q->debugfs_dir);
+
+	debugfs_create_files(q, hctx->debugfs_dir, hctx,
+			     blk_mq_debugfs_hctx_attrs);
+
+	hctx_for_each_ctx(hctx, ctx, i)
+		blk_mq_debugfs_register_ctx(hctx, ctx);
+}
+
+void blk_mq_debugfs_unregister_hctx(struct blk_mq_hw_ctx *hctx)
+{
+	if (!hctx->queue->debugfs_dir)
+		return;
+	debugfs_remove_recursive(hctx->debugfs_dir);
+	hctx->sched_debugfs_dir = NULL;
+	hctx->debugfs_dir = NULL;
+}
+
+void blk_mq_debugfs_register_hctxs(struct request_queue *q)
+{
+	struct blk_mq_hw_ctx *hctx;
+	unsigned int memflags;
+	unsigned long i;
+
+	memflags = blk_debugfs_lock(q);
+	queue_for_each_hw_ctx(q, hctx, i)
+		blk_mq_debugfs_register_hctx(q, hctx);
+	blk_debugfs_unlock(q, memflags);
+}
+
+void blk_mq_debugfs_unregister_hctxs(struct request_queue *q)
+{
+	struct blk_mq_hw_ctx *hctx;
+	unsigned long i;
+
+	queue_for_each_hw_ctx(q, hctx, i)
+		blk_mq_debugfs_unregister_hctx(hctx);
+}
+
+void blk_mq_debugfs_register_sched(struct request_queue *q)
+{
+	struct elevator_type *e = q->elevator->type;
+
+	lockdep_assert_held(&q->debugfs_mutex);
+
+	/*
+	 * If the parent directory has not been created yet, return, we will be
+	 * called again later on and the directory/files will be created then.
+	 */
+	if (!q->debugfs_dir)
+		return;
+
+	if (!e->queue_debugfs_attrs)
+		return;
+
+	q->sched_debugfs_dir = debugfs_create_dir("sched", q->debugfs_dir);
+
+	debugfs_create_files(q, q->sched_debugfs_dir, q, e->queue_debugfs_attrs);
+}
+
+void blk_mq_debugfs_unregister_sched(struct request_queue *q)
+{
+	lockdep_assert_held(&q->debugfs_mutex);
+
+	debugfs_remove_recursive(q->sched_debugfs_dir);
+	q->sched_debugfs_dir = NULL;
+}
+
+static const char *rq_qos_id_to_name(enum rq_qos_id id)
+{
+	switch (id) {
+	case RQ_QOS_WBT:
+		return "wbt";
+	case RQ_QOS_LATENCY:
+		return "latency";
+	case RQ_QOS_COST:
+		return "cost";
+	}
+	return "unknown";
+}
+
+static void blk_mq_debugfs_register_rqos(struct rq_qos *rqos)
+{
+	struct request_queue *q = rqos->disk->queue;
+	const char *dir_name = rq_qos_id_to_name(rqos->id);
+
+	lockdep_assert_held(&q->debugfs_mutex);
+
+	if (rqos->debugfs_dir || !rqos->ops->debugfs_attrs)
+		return;
+
+	if (!q->rqos_debugfs_dir)
+		q->rqos_debugfs_dir = debugfs_create_dir("rqos",
+							 q->debugfs_dir);
+
+	rqos->debugfs_dir = debugfs_create_dir(dir_name, q->rqos_debugfs_dir);
+	debugfs_create_files(q, rqos->debugfs_dir, rqos,
+			     rqos->ops->debugfs_attrs);
+}
+
+void blk_mq_debugfs_register_rq_qos(struct request_queue *q)
+{
+	lockdep_assert_held(&q->debugfs_mutex);
+
+	if (q->rq_qos) {
+		struct rq_qos *rqos = q->rq_qos;
+
+		while (rqos) {
+			blk_mq_debugfs_register_rqos(rqos);
+			rqos = rqos->next;
+		}
+	}
+}
+
+void blk_mq_debugfs_register_sched_hctx(struct request_queue *q,
+					struct blk_mq_hw_ctx *hctx)
+{
+	struct elevator_type *e = q->elevator->type;
+
+	lockdep_assert_held(&q->debugfs_mutex);
+
+	/*
+	 * If the parent debugfs directory has not been created yet, return;
+	 * We will be called again later on with appropriate parent debugfs
+	 * directory from blk_register_queue()
+	 */
+	if (!hctx->debugfs_dir)
+		return;
+
+	if (!e->hctx_debugfs_attrs)
+		return;
+
+	hctx->sched_debugfs_dir = debugfs_create_dir("sched",
+						     hctx->debugfs_dir);
+	debugfs_create_files(q, hctx->sched_debugfs_dir, hctx,
+			     e->hctx_debugfs_attrs);
+}
+
+void blk_mq_debugfs_unregister_sched_hctx(struct blk_mq_hw_ctx *hctx)
+{
+	lockdep_assert_held(&hctx->queue->debugfs_mutex);
+
+	if (!hctx->queue->debugfs_dir)
+		return;
+	debugfs_remove_recursive(hctx->sched_debugfs_dir);
+	hctx->sched_debugfs_dir = NULL;
+}