dm vdo wait-queue: add proper namespace to interface

Rename various interfaces and structs associated with vdo's wait-queue,
e.g.: s/wait_queue/vdo_wait_queue/, s/waiter/vdo_waiter/, etc.

Now all function names start with "vdo_waitq_" or "vdo_waiter_".
Reviewed-by: Ken Raeburn <raeburn@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@kernel.org>
Signed-off-by: Matthew Sakai <msakai@redhat.com>

drivers/md/dm-vdo/block-map.h

@@ -68,7 +68,7 @@ struct vdo_page_cache {
 	/* how many VPCs waiting for free page */
 	unsigned int waiter_count;
 	/* queue of waiters who want a free page */
-	struct wait_queue free_waiters;
+	struct vdo_wait_queue free_waiters;
 	/*
 	 * Statistics are only updated on the logical zone thread, but are accessed from other
 	 * threads.
@@ -129,7 +129,7 @@ struct page_info {
 	/* page state */
 	enum vdo_page_buffer_state state;
 	/* queue of completions awaiting this item */
-	struct wait_queue waiting;
+	struct vdo_wait_queue waiting;
 	/* state linked list entry */
 	struct list_head state_entry;
 	/* LRU entry */
@@ -153,7 +153,7 @@ struct vdo_page_completion {
 	/* The cache involved */
 	struct vdo_page_cache *cache;
 	/* The waiter for the pending list */
-	struct waiter waiter;
+	struct vdo_waiter waiter;
 	/* The absolute physical block number of the page on disk */
 	physical_block_number_t pbn;
 	/* Whether the page may be modified */
@@ -167,7 +167,7 @@ struct vdo_page_completion {
 struct forest;
 
 struct tree_page {
-	struct waiter waiter;
+	struct vdo_waiter waiter;
 
 	/* Dirty list entry */
 	struct list_head entry;
@@ -228,7 +228,7 @@ struct block_map_zone {
 	struct vio_pool *vio_pool;
 	/* The tree page which has issued or will be issuing a flush */
 	struct tree_page *flusher;
-	struct wait_queue flush_waiters;
+	struct vdo_wait_queue flush_waiters;
 	/* The generation after the most recent flush */
 	u8 generation;
 	u8 oldest_generation;

drivers/md/dm-vdo/data-vio.c

@@ -249,7 +249,7 @@ static void initialize_lbn_lock(struct data_vio *data_vio, logical_block_number_
 
 	lock->lbn = lbn;
 	lock->locked = false;
-	vdo_initialize_wait_queue(&lock->waiters);
+	vdo_waitq_init(&lock->waiters);
 	zone_number = vdo_compute_logical_zone(data_vio);
 	lock->zone = &vdo->logical_zones->zones[zone_number];
 }
@@ -466,7 +466,7 @@ static void attempt_logical_block_lock(struct vdo_completion *completion)
 	}
 
 	data_vio->last_async_operation = VIO_ASYNC_OP_ATTEMPT_LOGICAL_BLOCK_LOCK;
-	vdo_enqueue_waiter(&lock_holder->logical.waiters, &data_vio->waiter);
+	vdo_waitq_enqueue_waiter(&lock_holder->logical.waiters, &data_vio->waiter);
 
 	/*
 	 * Prevent writes and read-modify-writes from blocking indefinitely on lock holders in the
@@ -1191,10 +1191,10 @@ static void transfer_lock(struct data_vio *data_vio, struct lbn_lock *lock)
 
 	/* Another data_vio is waiting for the lock, transfer it in a single lock map operation. */
 	next_lock_holder =
-		waiter_as_data_vio(vdo_dequeue_next_waiter(&lock->waiters));
+		vdo_waiter_as_data_vio(vdo_waitq_dequeue_next_waiter(&lock->waiters));
 
 	/* Transfer the remaining lock waiters to the next lock holder. */
-	vdo_transfer_all_waiters(&lock->waiters,
+	vdo_waitq_transfer_all_waiters(&lock->waiters,
 				       &next_lock_holder->logical.waiters);
 
 	result = vdo_int_map_put(lock->zone->lbn_operations, lock->lbn,
@@ -1213,7 +1213,7 @@ static void transfer_lock(struct data_vio *data_vio, struct lbn_lock *lock)
 	 * If there are still waiters, other data_vios must be trying to get the lock we just
 	 * transferred. We must ensure that the new lock holder doesn't block in the packer.
 	 */
-	if (vdo_has_waiters(&next_lock_holder->logical.waiters))
+	if (vdo_waitq_has_waiters(&next_lock_holder->logical.waiters))
 		cancel_data_vio_compression(next_lock_holder);
 
 	/*
@@ -1235,7 +1235,7 @@ static void release_logical_lock(struct vdo_completion *completion)
 
 	assert_data_vio_in_logical_zone(data_vio);
 
-	if (vdo_has_waiters(&lock->waiters))
+	if (vdo_waitq_has_waiters(&lock->waiters))
 		transfer_lock(data_vio, lock);
 	else
 		release_lock(data_vio, lock);

drivers/md/dm-vdo/data-vio.h

@@ -54,7 +54,7 @@ enum async_operation_number {
 struct lbn_lock {
 	logical_block_number_t lbn;
 	bool locked;
-	struct wait_queue waiters;
+	struct vdo_wait_queue waiters;
 	struct logical_zone *zone;
 };
 
@@ -75,7 +75,7 @@ struct tree_lock {
 	/* The key for the lock map */
 	u64 key;
 	/* The queue of waiters for the page this vio is allocating or loading */
-	struct wait_queue waiters;
+	struct vdo_wait_queue waiters;
 	/* The block map tree slots for this LBN */
 	struct block_map_tree_slot tree_slots[VDO_BLOCK_MAP_TREE_HEIGHT + 1];
 };
@@ -168,13 +168,13 @@ struct reference_updater {
 	bool increment;
 	struct zoned_pbn zpbn;
 	struct pbn_lock *lock;
-	struct waiter waiter;
+	struct vdo_waiter waiter;
 };
 
 /* A vio for processing user data requests. */
 struct data_vio {
-	/* The wait_queue entry structure */
-	struct waiter waiter;
+	/* The vdo_wait_queue entry structure */
+	struct vdo_waiter waiter;
 
 	/* The logical block of this request */
 	struct lbn_lock logical;
@@ -288,7 +288,7 @@ static inline struct data_vio *as_data_vio(struct vdo_completion *completion)
 	return vio_as_data_vio(as_vio(completion));
 }
 
-static inline struct data_vio *waiter_as_data_vio(struct waiter *waiter)
+static inline struct data_vio *vdo_waiter_as_data_vio(struct vdo_waiter *waiter)
 {
 	if (waiter == NULL)
 		return NULL;

drivers/md/dm-vdo/dedupe.c

@@ -270,7 +270,7 @@ struct hash_lock {
 	 * to get the information they all need to deduplicate--either against each other, or
 	 * against an existing duplicate on disk.
 	 */
-	struct wait_queue waiters;
+	struct vdo_wait_queue waiters;
 };
 
 enum {
@@ -351,7 +351,7 @@ static void return_hash_lock_to_pool(struct hash_zone *zone, struct hash_lock *l
 	memset(lock, 0, sizeof(*lock));
 	INIT_LIST_HEAD(&lock->pool_node);
 	INIT_LIST_HEAD(&lock->duplicate_ring);
-	vdo_initialize_wait_queue(&lock->waiters);
+	vdo_waitq_init(&lock->waiters);
 	list_add_tail(&lock->pool_node, &zone->lock_pool);
 }
 
@@ -420,7 +420,7 @@ static void set_duplicate_lock(struct hash_lock *hash_lock, struct pbn_lock *pbn
  */
 static inline struct data_vio *dequeue_lock_waiter(struct hash_lock *lock)
 {
-	return waiter_as_data_vio(vdo_dequeue_next_waiter(&lock->waiters));
+	return vdo_waiter_as_data_vio(vdo_waitq_dequeue_next_waiter(&lock->waiters));
 }
 
 /**
@@ -536,7 +536,7 @@ static struct data_vio *retire_lock_agent(struct hash_lock *lock)
  */
 static void wait_on_hash_lock(struct hash_lock *lock, struct data_vio *data_vio)
 {
-	vdo_enqueue_waiter(&lock->waiters, &data_vio->waiter);
+	vdo_waitq_enqueue_waiter(&lock->waiters, &data_vio->waiter);
 
 	/*
 	 * Make sure the agent doesn't block indefinitely in the packer since it now has at least
@@ -562,9 +562,9 @@ static void wait_on_hash_lock(struct hash_lock *lock, struct data_vio *data_vio)
  * @waiter: The data_vio's waiter link.
  * @context: Not used.
  */
-static void abort_waiter(struct waiter *waiter, void *context __always_unused)
+static void abort_waiter(struct vdo_waiter *waiter, void *context __always_unused)
 {
-	write_data_vio(waiter_as_data_vio(waiter));
+	write_data_vio(vdo_waiter_as_data_vio(waiter));
 }
 
 /**
@@ -602,7 +602,7 @@ void vdo_clean_failed_hash_lock(struct data_vio *data_vio)
 	/* Ensure we don't attempt to update advice when cleaning up. */
 	lock->update_advice = false;
 
-	vdo_notify_all_waiters(&lock->waiters, abort_waiter, NULL);
+	vdo_waitq_notify_all_waiters(&lock->waiters, abort_waiter, NULL);
 
 	if (lock->duplicate_lock != NULL) {
 		/* The agent must reference the duplicate zone to launch it. */
@@ -650,7 +650,7 @@ static void finish_unlocking(struct vdo_completion *completion)
 	 */
 	lock->verified = false;
 
-	if (vdo_has_waiters(&lock->waiters)) {
+	if (vdo_waitq_has_waiters(&lock->waiters)) {
 		/*
 		 * UNLOCKING -> LOCKING transition: A new data_vio entered the hash lock while the
 		 * agent was releasing the PBN lock. The current agent exits and the waiter has to
@@ -750,7 +750,7 @@ static void finish_updating(struct vdo_completion *completion)
 	 */
 	lock->update_advice = false;
 
-	if (vdo_has_waiters(&lock->waiters)) {
+	if (vdo_waitq_has_waiters(&lock->waiters)) {
 		/*
 		 * UPDATING -> DEDUPING transition: A new data_vio arrived during the UDS update.
 		 * Send it on the verified dedupe path. The agent is done with the lock, but the
@@ -812,7 +812,7 @@ static void finish_deduping(struct hash_lock *lock, struct data_vio *data_vio)
 	struct data_vio *agent = data_vio;
 
 	ASSERT_LOG_ONLY(lock->agent == NULL, "shouldn't have an agent in DEDUPING");
-	ASSERT_LOG_ONLY(!vdo_has_waiters(&lock->waiters),
+	ASSERT_LOG_ONLY(!vdo_waitq_has_waiters(&lock->waiters),
 			"shouldn't have any lock waiters in DEDUPING");
 
 	/* Just release the lock reference if other data_vios are still deduping. */
@@ -917,9 +917,9 @@ static int __must_check acquire_lock(struct hash_zone *zone,
  * Implements waiter_callback_fn. Binds the data_vio that was waiting to a new hash lock and waits
  * on that lock.
  */
-static void enter_forked_lock(struct waiter *waiter, void *context)
+static void enter_forked_lock(struct vdo_waiter *waiter, void *context)
 {
-	struct data_vio *data_vio = waiter_as_data_vio(waiter);
+	struct data_vio *data_vio = vdo_waiter_as_data_vio(waiter);
 	struct hash_lock *new_lock = context;
 
 	set_hash_lock(data_vio, new_lock);
@@ -956,7 +956,7 @@ static void fork_hash_lock(struct hash_lock *old_lock, struct data_vio *new_agen
 	set_hash_lock(new_agent, new_lock);
 	new_lock->agent = new_agent;
 
-	vdo_notify_all_waiters(&old_lock->waiters, enter_forked_lock, new_lock);
+	vdo_waitq_notify_all_waiters(&old_lock->waiters, enter_forked_lock, new_lock);
 
 	new_agent->is_duplicate = false;
 	start_writing(new_lock, new_agent);
@@ -1033,7 +1033,7 @@ static void start_deduping(struct hash_lock *lock, struct data_vio *agent,
 		launch_dedupe(lock, agent, true);
 		agent = NULL;
 	}
-	while (vdo_has_waiters(&lock->waiters))
+	while (vdo_waitq_has_waiters(&lock->waiters))
 		launch_dedupe(lock, dequeue_lock_waiter(lock), false);
 
 	if (agent_is_done) {
@@ -1454,7 +1454,7 @@ static void finish_writing(struct hash_lock *lock, struct data_vio *agent)
 		lock->update_advice = true;
 
 	/* If there are any waiters, we need to start deduping them. */
-	if (vdo_has_waiters(&lock->waiters)) {
+	if (vdo_waitq_has_waiters(&lock->waiters)) {
 		/*
 		 * WRITING -> DEDUPING transition: an asynchronously-written block failed to
 		 * compress, so the PBN lock on the written copy was already transferred. The agent
@@ -1502,10 +1502,10 @@ static void finish_writing(struct hash_lock *lock, struct data_vio *agent)
  */
 static struct data_vio *select_writing_agent(struct hash_lock *lock)
 {
-	struct wait_queue temp_queue;
+	struct vdo_wait_queue temp_queue;
 	struct data_vio *data_vio;
 
-	vdo_initialize_wait_queue(&temp_queue);
+	vdo_waitq_init(&temp_queue);
 
 	/*
 	 * Move waiters to the temp queue one-by-one until we find an allocation. Not ideal to
@@ -1514,7 +1514,7 @@ static struct data_vio *select_writing_agent(struct hash_lock *lock)
 	while (((data_vio = dequeue_lock_waiter(lock)) != NULL) &&
 	       !data_vio_has_allocation(data_vio)) {
 		/* Use the lower-level enqueue since we're just moving waiters around. */
-		vdo_enqueue_waiter(&temp_queue, &data_vio->waiter);
+		vdo_waitq_enqueue_waiter(&temp_queue, &data_vio->waiter);
 	}
 
 	if (data_vio != NULL) {
@@ -1522,13 +1522,13 @@ static struct data_vio *select_writing_agent(struct hash_lock *lock)
 		 * Move the rest of the waiters over to the temp queue, preserving the order they
 		 * arrived at the lock.
 		 */
-		vdo_transfer_all_waiters(&lock->waiters, &temp_queue);
+		vdo_waitq_transfer_all_waiters(&lock->waiters, &temp_queue);
 
 		/*
 		 * The current agent is being replaced and will have to wait to dedupe; make it the
 		 * first waiter since it was the first to reach the lock.
 		 */
-		vdo_enqueue_waiter(&lock->waiters, &lock->agent->waiter);
+		vdo_waitq_enqueue_waiter(&lock->waiters, &lock->agent->waiter);
 		lock->agent = data_vio;
 	} else {
 		/* No one has an allocation, so keep the current agent. */
@@ -1536,7 +1536,7 @@ static struct data_vio *select_writing_agent(struct hash_lock *lock)
 	}
 
 	/* Swap all the waiters back onto the lock's queue. */
-	vdo_transfer_all_waiters(&temp_queue, &lock->waiters);
+	vdo_waitq_transfer_all_waiters(&temp_queue, &lock->waiters);
 	return data_vio;
 }
 
@@ -1577,7 +1577,7 @@ static void start_writing(struct hash_lock *lock, struct data_vio *agent)
 	 * If the agent compresses, it might wait indefinitely in the packer, which would be bad if
 	 * there are any other data_vios waiting.
 	 */
-	if (vdo_has_waiters(&lock->waiters))
+	if (vdo_waitq_has_waiters(&lock->waiters))
 		cancel_data_vio_compression(agent);
 
 	/*
@@ -1928,7 +1928,7 @@ void vdo_release_hash_lock(struct data_vio *data_vio)
 				"unregistered hash lock must not be in the lock map");
 	}
 
-	ASSERT_LOG_ONLY(!vdo_has_waiters(&lock->waiters),
+	ASSERT_LOG_ONLY(!vdo_waitq_has_waiters(&lock->waiters),
 			"hash lock returned to zone must have no waiters");
 	ASSERT_LOG_ONLY((lock->duplicate_lock == NULL),
 			"hash lock returned to zone must not reference a PBN lock");
@@ -2812,7 +2812,7 @@ static void dump_hash_lock(const struct hash_lock *lock)
 		     lock, state, (lock->registered ? 'D' : 'U'),
 		     (unsigned long long) lock->duplicate.pbn,
 		     lock->duplicate.state, lock->reference_count,
-		     vdo_count_waiters(&lock->waiters), lock->agent);
+		     vdo_waitq_num_waiters(&lock->waiters), lock->agent);
 }
 
 static const char *index_state_to_string(struct hash_zones *zones,

drivers/md/dm-vdo/dump.c

@@ -146,25 +146,25 @@ void vdo_dump_all(struct vdo *vdo, const char *why)
 }
 
 /*
- * Dump out the data_vio waiters on a wait queue.
+ * Dump out the data_vio waiters on a waitq.
  * wait_on should be the label to print for queue (e.g. logical or physical)
  */
-static void dump_vio_waiters(struct wait_queue *queue, char *wait_on)
+static void dump_vio_waiters(struct vdo_wait_queue *waitq, char *wait_on)
 {
-	struct waiter *waiter, *first = vdo_get_first_waiter(queue);
+	struct vdo_waiter *waiter, *first = vdo_waitq_get_first_waiter(waitq);
 	struct data_vio *data_vio;
 
 	if (first == NULL)
 		return;
 
-	data_vio = waiter_as_data_vio(first);
+	data_vio = vdo_waiter_as_data_vio(first);
 
 	uds_log_info("      %s is locked. Waited on by: vio %px pbn %llu lbn %llu d-pbn %llu lastOp %s",
 		     wait_on, data_vio, data_vio->allocation.pbn, data_vio->logical.lbn,
 		     data_vio->duplicate.pbn, get_data_vio_operation_name(data_vio));
 
 	for (waiter = first->next_waiter; waiter != first; waiter = waiter->next_waiter) {
-		data_vio = waiter_as_data_vio(waiter);
+		data_vio = vdo_waiter_as_data_vio(waiter);
 		uds_log_info("     ... and : vio %px pbn %llu lbn %llu d-pbn %llu lastOp %s",
 			     data_vio, data_vio->allocation.pbn, data_vio->logical.lbn,
 			     data_vio->duplicate.pbn,
@@ -177,7 +177,7 @@ static void dump_vio_waiters(struct wait_queue *queue, char *wait_on)
  * logging brevity:
  *
  * R => vio completion result not VDO_SUCCESS
- * W => vio is on a wait queue
+ * W => vio is on a waitq
  * D => vio is a duplicate
  * p => vio is a partial block operation
  * z => vio is a zero block

drivers/md/dm-vdo/flush.c

@@ -31,9 +31,9 @@ struct flusher {
 	/** The first unacknowledged flush generation */
 	sequence_number_t first_unacknowledged_generation;
 	/** The queue of flush requests waiting to notify other threads */
-	struct wait_queue notifiers;
+	struct vdo_wait_queue notifiers;
 	/** The queue of flush requests waiting for VIOs to complete */
-	struct wait_queue pending_flushes;
+	struct vdo_wait_queue pending_flushes;
 	/** The flush generation for which notifications are being sent */
 	sequence_number_t notify_generation;
 	/** The logical zone to notify next */
@@ -93,7 +93,7 @@ static inline struct vdo_flush *completion_as_vdo_flush(struct vdo_completion *c
  *
  * Return: The wait queue entry as a vdo_flush.
  */
-static struct vdo_flush *waiter_as_flush(struct waiter *waiter)
+static struct vdo_flush *vdo_waiter_as_flush(struct vdo_waiter *waiter)
 {
 	return container_of(waiter, struct vdo_flush, waiter);
 }
@@ -195,10 +195,10 @@ static void finish_notification(struct vdo_completion *completion)
 
 	assert_on_flusher_thread(flusher, __func__);
 
-	vdo_enqueue_waiter(&flusher->pending_flushes,
-			   vdo_dequeue_next_waiter(&flusher->notifiers));
+	vdo_waitq_enqueue_waiter(&flusher->pending_flushes,
+				 vdo_waitq_dequeue_next_waiter(&flusher->notifiers));
 	vdo_complete_flushes(flusher);
-	if (vdo_has_waiters(&flusher->notifiers))
+	if (vdo_waitq_has_waiters(&flusher->notifiers))
 		notify_flush(flusher);
 }
 
@@ -248,7 +248,8 @@ static void increment_generation(struct vdo_completion *completion)
  */
 static void notify_flush(struct flusher *flusher)
 {
-	struct vdo_flush *flush = waiter_as_flush(vdo_get_first_waiter(&flusher->notifiers));
+	struct vdo_flush *flush =
+		vdo_waiter_as_flush(vdo_waitq_get_first_waiter(&flusher->notifiers));
 
 	flusher->notify_generation = flush->flush_generation;
 	flusher->logical_zone_to_notify = &flusher->vdo->logical_zones->zones[0];
@@ -280,8 +281,8 @@ static void flush_vdo(struct vdo_completion *completion)
 	}
 
 	flush->flush_generation = flusher->flush_generation++;
-	may_notify = !vdo_has_waiters(&flusher->notifiers);
-	vdo_enqueue_waiter(&flusher->notifiers, &flush->waiter);
+	may_notify = !vdo_waitq_has_waiters(&flusher->notifiers);
+	vdo_waitq_enqueue_waiter(&flusher->notifiers, &flush->waiter);
 	if (may_notify)
 		notify_flush(flusher);
 }
@@ -294,7 +295,8 @@ static void check_for_drain_complete(struct flusher *flusher)
 {
 	bool drained;
 
-	if (!vdo_is_state_draining(&flusher->state) || vdo_has_waiters(&flusher->pending_flushes))
+	if (!vdo_is_state_draining(&flusher->state) ||
+	    vdo_waitq_has_waiters(&flusher->pending_flushes))
 		return;
 
 	spin_lock(&flusher->lock);
@@ -321,9 +323,9 @@ void vdo_complete_flushes(struct flusher *flusher)
 			min(oldest_active_generation,
 			    READ_ONCE(zone->oldest_active_generation));
 
-	while (vdo_has_waiters(&flusher->pending_flushes)) {
+	while (vdo_waitq_has_waiters(&flusher->pending_flushes)) {
 		struct vdo_flush *flush =
-			waiter_as_flush(vdo_get_first_waiter(&flusher->pending_flushes));
+			vdo_waiter_as_flush(vdo_waitq_get_first_waiter(&flusher->pending_flushes));
 
 		if (flush->flush_generation >= oldest_active_generation)
 			return;
@@ -333,7 +335,7 @@ void vdo_complete_flushes(struct flusher *flusher)
 				"acknowledged next expected flush, %llu, was: %llu",
 				(unsigned long long) flusher->first_unacknowledged_generation,
 				(unsigned long long) flush->flush_generation);
-		vdo_dequeue_next_waiter(&flusher->pending_flushes);
+		vdo_waitq_dequeue_next_waiter(&flusher->pending_flushes);
 		vdo_complete_flush(flush);
 		flusher->first_unacknowledged_generation++;
 	}
@@ -352,8 +354,8 @@ void vdo_dump_flusher(const struct flusher *flusher)
 		     (unsigned long long) flusher->flush_generation,
 		     (unsigned long long) flusher->first_unacknowledged_generation);
 	uds_log_info("  notifiers queue is %s; pending_flushes queue is %s",
-		     (vdo_has_waiters(&flusher->notifiers) ? "not empty" : "empty"),
-		     (vdo_has_waiters(&flusher->pending_flushes) ? "not empty" : "empty"));
+		     (vdo_waitq_has_waiters(&flusher->notifiers) ? "not empty" : "empty"),
+		     (vdo_waitq_has_waiters(&flusher->pending_flushes) ? "not empty" : "empty"));
 }
 
 /**

drivers/md/dm-vdo/flush.h

@@ -18,7 +18,7 @@ struct vdo_flush {
 	/* The flush bios covered by this request */
 	struct bio_list bios;
 	/* The wait queue entry for this flush */
-	struct waiter waiter;
+	struct vdo_waiter waiter;
 	/* Which flush this struct represents */
 	sequence_number_t flush_generation;
 };

drivers/md/dm-vdo/physical-zone.c

@@ -519,9 +519,9 @@ static int allocate_and_lock_block(struct allocation *allocation)
  * @waiter: The allocating_vio that was waiting to allocate.
  * @context: The context (unused).
  */
-static void retry_allocation(struct waiter *waiter, void *context __always_unused)
+static void retry_allocation(struct vdo_waiter *waiter, void *context __always_unused)
 {
-	struct data_vio *data_vio = waiter_as_data_vio(waiter);
+	struct data_vio *data_vio = vdo_waiter_as_data_vio(waiter);
 
 	/* Now that some slab has scrubbed, restart the allocation process. */
 	data_vio->allocation.wait_for_clean_slab = false;

drivers/md/dm-vdo/recovery-journal.c

@@ -267,9 +267,9 @@ static void assert_on_journal_thread(struct recovery_journal *journal,
  * Invoked whenever a data_vio is to be released from the journal, either because its entry was
  * committed to disk, or because there was an error. Implements waiter_callback_fn.
  */
-static void continue_waiter(struct waiter *waiter, void *context)
+static void continue_waiter(struct vdo_waiter *waiter, void *context)
 {
-	continue_data_vio_with_error(waiter_as_data_vio(waiter), *((int *) context));
+	continue_data_vio_with_error(vdo_waiter_as_data_vio(waiter), *((int *) context));
 }
 
 /**
@@ -287,8 +287,8 @@ static inline bool has_block_waiters(struct recovery_journal *journal)
 	 * has waiters.
 	 */
 	return ((block != NULL) &&
-		(vdo_has_waiters(&block->entry_waiters) ||
-		 vdo_has_waiters(&block->commit_waiters)));
+		(vdo_waitq_has_waiters(&block->entry_waiters) ||
+		 vdo_waitq_has_waiters(&block->commit_waiters)));
 }
 
 static void recycle_journal_blocks(struct recovery_journal *journal);
@@ -343,14 +343,14 @@ static void check_for_drain_complete(struct recovery_journal *journal)
 		recycle_journal_blocks(journal);
 
 		/* Release any data_vios waiting to be assigned entries. */
-		vdo_notify_all_waiters(&journal->entry_waiters, continue_waiter,
-				       &result);
+		vdo_waitq_notify_all_waiters(&journal->entry_waiters,
+					     continue_waiter, &result);
 	}
 
 	if (!vdo_is_state_draining(&journal->state) ||
 	    journal->reaping ||
 	    has_block_waiters(journal) ||
-	    vdo_has_waiters(&journal->entry_waiters) ||
+	    vdo_waitq_has_waiters(&journal->entry_waiters) ||
 	    !suspend_lock_counter(&journal->lock_counter))
 		return;
 
@@ -721,7 +721,7 @@ int vdo_decode_recovery_journal(struct recovery_journal_state_7_0 state, nonce_t
 
 	INIT_LIST_HEAD(&journal->free_tail_blocks);
 	INIT_LIST_HEAD(&journal->active_tail_blocks);
-	vdo_initialize_wait_queue(&journal->pending_writes);
+	vdo_waitq_init(&journal->pending_writes);
 
 	journal->thread_id = vdo->thread_config.journal_thread;
 	journal->origin = partition->offset;
@@ -1047,7 +1047,7 @@ static void schedule_block_write(struct recovery_journal *journal,
 				 struct recovery_journal_block *block)
 {
 	if (!block->committing)
-		vdo_enqueue_waiter(&journal->pending_writes, &block->write_waiter);
+		vdo_waitq_enqueue_waiter(&journal->pending_writes, &block->write_waiter);
 	/*
 	 * At the end of adding entries, or discovering this partial block is now full and ready to
 	 * rewrite, we will call write_blocks() and write a whole batch.
@@ -1084,9 +1084,9 @@ static void update_usages(struct recovery_journal *journal, struct data_vio *dat
  *
  * Implements waiter_callback_fn.
  */
-static void assign_entry(struct waiter *waiter, void *context)
+static void assign_entry(struct vdo_waiter *waiter, void *context)
 {
-	struct data_vio *data_vio = waiter_as_data_vio(waiter);
+	struct data_vio *data_vio = vdo_waiter_as_data_vio(waiter);
 	struct recovery_journal_block *block = context;
 	struct recovery_journal *journal = block->journal;
 
@@ -1099,10 +1099,10 @@ static void assign_entry(struct waiter *waiter, void *context)
 	update_usages(journal, data_vio);
 	journal->available_space--;
 
-	if (!vdo_has_waiters(&block->entry_waiters))
+	if (!vdo_waitq_has_waiters(&block->entry_waiters))
 		journal->events.blocks.started++;
 
-	vdo_enqueue_waiter(&block->entry_waiters, &data_vio->waiter);
+	vdo_waitq_enqueue_waiter(&block->entry_waiters, &data_vio->waiter);
 	block->entry_count++;
 	block->uncommitted_entry_count++;
 	journal->events.entries.started++;
@@ -1127,9 +1127,10 @@ static void assign_entries(struct recovery_journal *journal)
 	}
 
 	journal->adding_entries = true;
-	while (vdo_has_waiters(&journal->entry_waiters) && prepare_to_assign_entry(journal)) {
-		vdo_notify_next_waiter(&journal->entry_waiters, assign_entry,
-				       journal->active_block);
+	while (vdo_waitq_has_waiters(&journal->entry_waiters) &&
+	       prepare_to_assign_entry(journal)) {
+		vdo_waitq_notify_next_waiter(&journal->entry_waiters,
+					     assign_entry, journal->active_block);
 	}
 
 	/* Now that we've finished with entries, see if we have a batch of blocks to write. */
@@ -1170,9 +1171,9 @@ static void recycle_journal_block(struct recovery_journal_block *block)
  *
  * Implements waiter_callback_fn.
  */
-static void continue_committed_waiter(struct waiter *waiter, void *context)
+static void continue_committed_waiter(struct vdo_waiter *waiter, void *context)
 {
-	struct data_vio *data_vio = waiter_as_data_vio(waiter);
+	struct data_vio *data_vio = vdo_waiter_as_data_vio(waiter);
 	struct recovery_journal *journal = context;
 	int result = (is_read_only(journal) ? VDO_READ_ONLY : VDO_SUCCESS);
 	bool has_decrement;
@@ -1216,11 +1217,12 @@ static void notify_commit_waiters(struct recovery_journal *journal)
 		if (block->committing)
 			return;
 
-		vdo_notify_all_waiters(&block->commit_waiters, continue_committed_waiter,
-				       journal);
-		if (is_read_only(journal)) {
-			vdo_notify_all_waiters(&block->entry_waiters,
+		vdo_waitq_notify_all_waiters(&block->commit_waiters,
 					     continue_committed_waiter, journal);
+		if (is_read_only(journal)) {
+			vdo_waitq_notify_all_waiters(&block->entry_waiters,
+						     continue_committed_waiter,
+						     journal);
 		} else if (is_block_dirty(block) || !is_block_full(block)) {
 			/* Stop at partially-committed or partially-filled blocks. */
 			return;
@@ -1328,9 +1330,9 @@ static void complete_write_endio(struct bio *bio)
  */
 static void add_queued_recovery_entries(struct recovery_journal_block *block)
 {
-	while (vdo_has_waiters(&block->entry_waiters)) {
+	while (vdo_waitq_has_waiters(&block->entry_waiters)) {
 		struct data_vio *data_vio =
-			waiter_as_data_vio(vdo_dequeue_next_waiter(&block->entry_waiters));
+			vdo_waiter_as_data_vio(vdo_waitq_dequeue_next_waiter(&block->entry_waiters));
 		struct tree_lock *lock = &data_vio->tree_lock;
 		struct packed_recovery_journal_entry *packed_entry;
 		struct recovery_journal_entry new_entry;
@@ -1357,7 +1359,7 @@ static void add_queued_recovery_entries(struct recovery_journal_block *block)
 		data_vio->recovery_sequence_number = block->sequence_number;
 
 		/* Enqueue the data_vio to wait for its entry to commit. */
-		vdo_enqueue_waiter(&block->commit_waiters, &data_vio->waiter);
+		vdo_waitq_enqueue_waiter(&block->commit_waiters, &data_vio->waiter);
 	}
 }
 
@@ -1366,17 +1368,18 @@ static void add_queued_recovery_entries(struct recovery_journal_block *block)
  *
  * Implements waiter_callback_fn.
  */
-static void write_block(struct waiter *waiter, void *context __always_unused)
+static void write_block(struct vdo_waiter *waiter, void *context __always_unused)
 {
 	struct recovery_journal_block *block =
 		container_of(waiter, struct recovery_journal_block, write_waiter);
 	struct recovery_journal *journal = block->journal;
 	struct packed_journal_header *header = get_block_header(block);
 
-	if (block->committing || !vdo_has_waiters(&block->entry_waiters) || is_read_only(journal))
+	if (block->committing || !vdo_waitq_has_waiters(&block->entry_waiters) ||
+	    is_read_only(journal))
 		return;
 
-	block->entries_in_commit = vdo_count_waiters(&block->entry_waiters);
+	block->entries_in_commit = vdo_waitq_num_waiters(&block->entry_waiters);
 	add_queued_recovery_entries(block);
 
 	journal->pending_write_count += 1;
@@ -1419,7 +1422,7 @@ static void write_blocks(struct recovery_journal *journal)
 		return;
 
 	/* Write all the full blocks. */
-	vdo_notify_all_waiters(&journal->pending_writes, write_block, NULL);
+	vdo_waitq_notify_all_waiters(&journal->pending_writes, write_block, NULL);
 
 	/*
 	 * Do we need to write the active block? Only if we have no outstanding writes, even after
@@ -1459,7 +1462,7 @@ void vdo_add_recovery_journal_entry(struct recovery_journal *journal,
 			"journal lock not held for new entry");
 
 	vdo_advance_journal_point(&journal->append_point, journal->entries_per_block);
-	vdo_enqueue_waiter(&journal->entry_waiters, &data_vio->waiter);
+	vdo_waitq_enqueue_waiter(&journal->entry_waiters, &data_vio->waiter);
 	assign_entries(journal);
 }
 
@@ -1721,8 +1724,8 @@ static void dump_recovery_block(const struct recovery_journal_block *block)
 	uds_log_info("    sequence number %llu; entries %u; %s; %zu entry waiters; %zu commit waiters",
 		     (unsigned long long) block->sequence_number, block->entry_count,
 		     (block->committing ? "committing" : "waiting"),
-		     vdo_count_waiters(&block->entry_waiters),
-		     vdo_count_waiters(&block->commit_waiters));
+		     vdo_waitq_num_waiters(&block->entry_waiters),
+		     vdo_waitq_num_waiters(&block->commit_waiters));
 }
 
 /**
@@ -1745,7 +1748,7 @@ void vdo_dump_recovery_journal_statistics(const struct recovery_journal *journal
 		     (unsigned long long) journal->slab_journal_reap_head,
 		     (unsigned long long) stats.disk_full,
 		     (unsigned long long) stats.slab_journal_commits_requested,
-		     vdo_count_waiters(&journal->entry_waiters));
+		     vdo_waitq_num_waiters(&journal->entry_waiters));
 	uds_log_info("	entries: started=%llu written=%llu committed=%llu",
 		     (unsigned long long) stats.entries.started,
 		     (unsigned long long) stats.entries.written,

drivers/md/dm-vdo/recovery-journal.h

@@ -113,7 +113,7 @@ struct recovery_journal_block {
 	/* The doubly linked pointers for the free or active lists */
 	struct list_head list_node;
 	/* The waiter for the pending full block list */
-	struct waiter write_waiter;
+	struct vdo_waiter write_waiter;
 	/* The journal to which this block belongs */
 	struct recovery_journal *journal;
 	/* A pointer to the current sector in the packed block buffer */
@@ -133,9 +133,9 @@ struct recovery_journal_block {
 	/* The number of new entries in the current commit */
 	journal_entry_count_t entries_in_commit;
 	/* The queue of vios which will make entries for the next commit */
-	struct wait_queue entry_waiters;
+	struct vdo_wait_queue entry_waiters;
 	/* The queue of vios waiting for the current commit */
-	struct wait_queue commit_waiters;
+	struct vdo_wait_queue commit_waiters;
 };
 
 struct recovery_journal {
@@ -146,7 +146,7 @@ struct recovery_journal {
 	/* The block map which can hold locks on this journal */
 	struct block_map *block_map;
 	/* The queue of vios waiting to make entries */
-	struct wait_queue entry_waiters;
+	struct vdo_wait_queue entry_waiters;
 	/* The number of free entries in the journal */
 	u64 available_space;
 	/* The number of decrement entries which need to be made */
@@ -184,7 +184,7 @@ struct recovery_journal {
 	/* A pointer to the active block (the one we are adding entries to now) */
 	struct recovery_journal_block *active_block;
 	/* Journal blocks that need writing */
-	struct wait_queue pending_writes;
+	struct vdo_wait_queue pending_writes;
 	/* The new block map reap head after reaping */
 	sequence_number_t block_map_reap_head;
 	/* The head block number for the block map rebuild range */

drivers/md/dm-vdo/slab-depot.h

@@ -60,13 +60,13 @@ struct journal_lock {
 
 struct slab_journal {
 	/* A waiter object for getting a VIO pool entry */
-	struct waiter resource_waiter;
+	struct vdo_waiter resource_waiter;
 	/* A waiter object for updating the slab summary */
-	struct waiter slab_summary_waiter;
+	struct vdo_waiter slab_summary_waiter;
 	/* A waiter object for getting a vio with which to flush */
-	struct waiter flush_waiter;
+	struct vdo_waiter flush_waiter;
 	/* The queue of VIOs waiting to make an entry */
-	struct wait_queue entry_waiters;
+	struct vdo_wait_queue entry_waiters;
 	/* The parent slab reference of this journal */
 	struct vdo_slab *slab;
 
@@ -149,7 +149,7 @@ struct slab_journal {
  */
 struct reference_block {
 	/* This block waits on the ref_counts to tell it to write */
-	struct waiter waiter;
+	struct vdo_waiter waiter;
 	/* The slab to which this reference_block belongs */
 	struct vdo_slab *slab;
 	/* The number of references in this block that represent allocations */
@@ -241,12 +241,12 @@ struct vdo_slab {
 	struct search_cursor search_cursor;
 
 	/* A list of the dirty blocks waiting to be written out */
-	struct wait_queue dirty_blocks;
+	struct vdo_wait_queue dirty_blocks;
 	/* The number of blocks which are currently writing */
 	size_t active_count;
 
 	/* A waiter object for updating the slab summary */
-	struct waiter summary_waiter;
+	struct vdo_waiter summary_waiter;
 
 	/* The latest slab journal for which there has been a reference count update */
 	struct journal_point slab_journal_point;
@@ -271,7 +271,7 @@ struct slab_scrubber {
 	/* The queue of slabs to scrub once there are no high_priority_slabs */
 	struct list_head slabs;
 	/* The queue of VIOs waiting for a slab to be scrubbed */
-	struct wait_queue waiters;
+	struct vdo_wait_queue waiters;
 
 	/*
 	 * The number of slabs that are unrecovered or being scrubbed. This field is modified by
@@ -341,9 +341,9 @@ struct slab_summary_block {
 	/* Whether this block has a write outstanding */
 	bool writing;
 	/* Ring of updates waiting on the outstanding write */
-	struct wait_queue current_update_waiters;
+	struct vdo_wait_queue current_update_waiters;
 	/* Ring of updates waiting on the next write */
-	struct wait_queue next_update_waiters;
+	struct vdo_wait_queue next_update_waiters;
 	/* The active slab_summary_entry array for this block */
 	struct slab_summary_entry *entries;
 	/* The vio used to write this block */
@@ -522,7 +522,7 @@ int __must_check vdo_allocate_block(struct block_allocator *allocator,
 				    physical_block_number_t *block_number_ptr);
 
 int vdo_enqueue_clean_slab_waiter(struct block_allocator *allocator,
-				  struct waiter *waiter);
+				  struct vdo_waiter *waiter);
 
 void vdo_modify_reference_count(struct vdo_completion *completion,
 				struct reference_updater *updater);

drivers/md/dm-vdo/vio.c

@@ -25,7 +25,7 @@ struct vio_pool {
 	/** The list of objects which are available */
 	struct list_head available;
 	/** The queue of requestors waiting for objects from the pool */
-	struct wait_queue waiting;
+	struct vdo_wait_queue waiting;
 	/** The number of objects currently in use */
 	size_t busy_count;
 	/** The list of objects which are in use */
@@ -364,7 +364,7 @@ void free_vio_pool(struct vio_pool *pool)
 		return;
 
 	/* Remove all available vios from the object pool. */
-	ASSERT_LOG_ONLY(!vdo_has_waiters(&pool->waiting),
+	ASSERT_LOG_ONLY(!vdo_waitq_has_waiters(&pool->waiting),
 			"VIO pool must not have any waiters when being freed");
 	ASSERT_LOG_ONLY((pool->busy_count == 0),
 			"VIO pool must not have %zu busy entries when being freed",
@@ -400,7 +400,7 @@ bool is_vio_pool_busy(struct vio_pool *pool)
  * @pool: The vio pool.
  * @waiter: Object that is requesting a vio.
  */
-void acquire_vio_from_pool(struct vio_pool *pool, struct waiter *waiter)
+void acquire_vio_from_pool(struct vio_pool *pool, struct vdo_waiter *waiter)
 {
 	struct pooled_vio *pooled;
 
@@ -408,7 +408,7 @@ void acquire_vio_from_pool(struct vio_pool *pool, struct waiter *waiter)
 			"acquire from active vio_pool called from correct thread");
 
 	if (list_empty(&pool->available)) {
-		vdo_enqueue_waiter(&pool->waiting, waiter);
+		vdo_waitq_enqueue_waiter(&pool->waiting, waiter);
 		return;
 	}
 
@@ -430,8 +430,8 @@ void return_vio_to_pool(struct vio_pool *pool, struct pooled_vio *vio)
 
 	vio->vio.completion.error_handler = NULL;
 	vio->vio.completion.parent = NULL;
-	if (vdo_has_waiters(&pool->waiting)) {
-		vdo_notify_next_waiter(&pool->waiting, NULL, vio);
+	if (vdo_waitq_has_waiters(&pool->waiting)) {
+		vdo_waitq_notify_next_waiter(&pool->waiting, NULL, vio);
 		return;
 	}
 

drivers/md/dm-vdo/vio.h

@@ -193,7 +193,7 @@ int __must_check make_vio_pool(struct vdo *vdo, size_t pool_size, thread_id_t th
 			       void *context, struct vio_pool **pool_ptr);
 void free_vio_pool(struct vio_pool *pool);
 bool __must_check is_vio_pool_busy(struct vio_pool *pool);
-void acquire_vio_from_pool(struct vio_pool *pool, struct waiter *waiter);
+void acquire_vio_from_pool(struct vio_pool *pool, struct vdo_waiter *waiter);
 void return_vio_to_pool(struct vio_pool *pool, struct pooled_vio *vio);
 
 #endif /* VIO_H */

drivers/md/dm-vdo/wait-queue.h

@@ -10,122 +10,132 @@
 #include <linux/types.h>
 
 /**
- * DOC: Wait queues.
+ * A vdo_wait_queue is a circular singly linked list of entries waiting to be notified
+ * of a change in a condition. Keeping a circular list allows the vdo_wait_queue
+ * structure to simply be a pointer to the tail (newest) entry, supporting
+ * constant-time enqueue and dequeue operations. A null pointer is an empty waitq.
  *
- * A wait queue is a circular list of entries waiting to be notified of a change in a condition.
- * Keeping a circular list allows the queue structure to simply be a pointer to the tail (newest)
- * entry in the queue, supporting constant-time enqueue and dequeue operations. A null pointer is
- * an empty queue.
+ *   An empty waitq:
+ *     waitq0.last_waiter -> NULL
  *
- *   An empty queue:
- *     queue0.last_waiter -> NULL
+ *   A singleton waitq:
+ *     waitq1.last_waiter -> entry1 -> entry1 -> [...]
  *
- *   A singleton queue:
- *     queue1.last_waiter -> entry1 -> entry1 -> [...]
+ *   A three-element waitq:
+ *     waitq2.last_waiter -> entry3 -> entry1 -> entry2 -> entry3 -> [...]
  *
- *   A three-element queue:
- *     queue2.last_waiter -> entry3 -> entry1 -> entry2 -> entry3 -> [...]
+ *   linux/wait.h's wait_queue_head is _not_ used because vdo_wait_queue's
+ *   interface is much less complex (doesn't need locking, priorities or timers).
+ *   Made possible by vdo's thread-based resource allocation and locking; and
+ *   the polling nature of vdo_wait_queue consumers.
+ *
+ *   FIXME: could be made to use a linux/list.h's list_head but its extra barriers
+ *   really aren't needed. Nor is a doubly linked list, but vdo_wait_queue could
+ *   make use of __list_del_clearprev() -- but that would compromise the ability
+ *   to make full use of linux's list interface.
  */
 
-struct waiter;
+struct vdo_waiter;
 
-struct wait_queue {
+struct vdo_wait_queue {
 	/* The tail of the queue, the last (most recently added) entry */
-	struct waiter *last_waiter;
+	struct vdo_waiter *last_waiter;
 	/* The number of waiters currently in the queue */
-	size_t queue_length;
+	size_t length;
 };
 
 /**
- * typedef waiter_callback_fn - Callback type for functions which will be called to resume
- *                              processing of a waiter after it has been removed from its wait
- *                              queue.
+ * vdo_waiter_callback_fn - Callback type that will be called to resume processing
+ *                          of a waiter after it has been removed from its wait queue.
  */
-typedef void (*waiter_callback_fn)(struct waiter *waiter, void *context);
+typedef void (*vdo_waiter_callback_fn)(struct vdo_waiter *waiter, void *context);
 
 /**
- * typedef waiter_match_fn - Method type for waiter matching methods.
+ * vdo_waiter_match_fn - Method type for waiter matching methods.
  *
- * A waiter_match_fn method returns false if the waiter does not match.
+ * Returns false if the waiter does not match.
  */
-typedef bool (*waiter_match_fn)(struct waiter *waiter, void *context);
+typedef bool (*vdo_waiter_match_fn)(struct vdo_waiter *waiter, void *context);
 
-/* The queue entry structure for entries in a wait_queue. */
-struct waiter {
+/* The structure for entries in a vdo_wait_queue. */
+struct vdo_waiter {
 	/*
-	 * The next waiter in the queue. If this entry is the last waiter, then this is actually a
-	 * pointer back to the head of the queue.
+	 * The next waiter in the waitq. If this entry is the last waiter, then this
+	 * is actually a pointer back to the head of the waitq.
 	 */
-	struct waiter *next_waiter;
+	struct vdo_waiter *next_waiter;
 
-	/* Optional waiter-specific callback to invoke when waking this waiter. */
-	waiter_callback_fn callback;
+	/* Optional waiter-specific callback to invoke when dequeuing this waiter. */
+	vdo_waiter_callback_fn callback;
 };
 
 /**
- * is_waiting() - Check whether a waiter is waiting.
+ * vdo_waiter_is_waiting() - Check whether a waiter is waiting.
  * @waiter: The waiter to check.
  *
- * Return: true if the waiter is on some wait_queue.
+ * Return: true if the waiter is on some vdo_wait_queue.
  */
-static inline bool vdo_is_waiting(struct waiter *waiter)
+static inline bool vdo_waiter_is_waiting(struct vdo_waiter *waiter)
 {
 	return (waiter->next_waiter != NULL);
 }
 
 /**
- * initialize_wait_queue() - Initialize a wait queue.
- * @queue: The queue to initialize.
+ * vdo_waitq_init() - Initialize a vdo_wait_queue.
+ * @waitq: The vdo_wait_queue to initialize.
  */
-static inline void vdo_initialize_wait_queue(struct wait_queue *queue)
+static inline void vdo_waitq_init(struct vdo_wait_queue *waitq)
 {
-	*queue = (struct wait_queue) {
+	*waitq = (struct vdo_wait_queue) {
 		.last_waiter = NULL,
-		.queue_length = 0,
+		.length = 0,
 	};
 }
 
 /**
- * has_waiters() - Check whether a wait queue has any entries waiting in it.
- * @queue: The queue to query.
+ * vdo_waitq_has_waiters() - Check whether a vdo_wait_queue has any entries waiting.
+ * @waitq: The vdo_wait_queue to query.
  *
- * Return: true if there are any waiters in the queue.
+ * Return: true if there are any waiters in the waitq.
  */
-static inline bool __must_check vdo_has_waiters(const struct wait_queue *queue)
+static inline bool __must_check vdo_waitq_has_waiters(const struct vdo_wait_queue *waitq)
 {
-	return (queue->last_waiter != NULL);
+	return (waitq->last_waiter != NULL);
 }
 
-void vdo_enqueue_waiter(struct wait_queue *queue, struct waiter *waiter);
+void vdo_waitq_enqueue_waiter(struct vdo_wait_queue *waitq,
+			      struct vdo_waiter *waiter);
 
-void vdo_notify_all_waiters(struct wait_queue *queue, waiter_callback_fn callback,
-			    void *context);
+void vdo_waitq_notify_all_waiters(struct vdo_wait_queue *waitq,
+				  vdo_waiter_callback_fn callback, void *context);
 
-bool vdo_notify_next_waiter(struct wait_queue *queue, waiter_callback_fn callback,
-			    void *context);
+bool vdo_waitq_notify_next_waiter(struct vdo_wait_queue *waitq,
+				  vdo_waiter_callback_fn callback, void *context);
 
-void vdo_transfer_all_waiters(struct wait_queue *from_queue,
-			      struct wait_queue *to_queue);
+void vdo_waitq_transfer_all_waiters(struct vdo_wait_queue *from_waitq,
+				    struct vdo_wait_queue *to_waitq);
 
-struct waiter *vdo_get_first_waiter(const struct wait_queue *queue);
+struct vdo_waiter *vdo_waitq_get_first_waiter(const struct vdo_wait_queue *waitq);
 
-void vdo_dequeue_matching_waiters(struct wait_queue *queue, waiter_match_fn match_method,
-				  void *match_context, struct wait_queue *matched_queue);
+void vdo_waitq_dequeue_matching_waiters(struct vdo_wait_queue *waitq,
+					vdo_waiter_match_fn waiter_match,
+					void *match_context,
+					struct vdo_wait_queue *matched_waitq);
 
-struct waiter *vdo_dequeue_next_waiter(struct wait_queue *queue);
+struct vdo_waiter *vdo_waitq_dequeue_next_waiter(struct vdo_wait_queue *waitq);
 
 /**
- * count_waiters() - Count the number of waiters in a wait queue.
- * @queue: The wait queue to query.
+ * vdo_waitq_num_waiters() - Return the number of waiters in a vdo_wait_queue.
+ * @waitq: The vdo_wait_queue to query.
  *
- * Return: The number of waiters in the queue.
+ * Return: The number of waiters in the waitq.
  */
-static inline size_t __must_check vdo_count_waiters(const struct wait_queue *queue)
+static inline size_t __must_check vdo_waitq_num_waiters(const struct vdo_wait_queue *waitq)
 {
-	return queue->queue_length;
+	return waitq->length;
 }
 
-const struct waiter * __must_check vdo_get_next_waiter(const struct wait_queue *queue,
-						       const struct waiter *waiter);
+const struct vdo_waiter * __must_check
+vdo_waitq_get_next_waiter(const struct vdo_wait_queue *waitq, const struct vdo_waiter *waiter);
 
 #endif /* VDO_WAIT_QUEUE_H */