1 files changed, 362 insertions, 0 deletions
diff --git a/drivers/md/dm-vdo/vdo.h b/drivers/md/dm-vdo/vdo.h
new file mode 100644
index 000000000000..483ae873e002
--- /dev/null
+++ b/drivers/md/dm-vdo/vdo.h
@@ -0,0 +1,362 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright 2023 Red Hat
+ */
+
+#ifndef VDO_H
+#define VDO_H
+
+#include <linux/atomic.h>
+#include <linux/blk_types.h>
+#include <linux/completion.h>
+#include <linux/dm-kcopyd.h>
+#include <linux/list.h>
+#include <linux/spinlock.h>
+
+#include "admin-state.h"
+#include "encodings.h"
+#include "funnel-workqueue.h"
+#include "packer.h"
+#include "physical-zone.h"
+#include "statistics.h"
+#include "thread-registry.h"
+#include "types.h"
+
+enum notifier_state {
+	/* Notifications are allowed but not in progress */
+	MAY_NOTIFY,
+	/* A notification is in progress */
+	NOTIFYING,
+	/* Notifications are not allowed */
+	MAY_NOT_NOTIFY,
+	/* A notification has completed */
+	NOTIFIED,
+};
+
+/**
+ * typedef vdo_read_only_notification_fn - A function to notify a listener that the VDO has gone
+ *                                         read-only.
+ * @listener: The object to notify.
+ * @parent: The completion to notify in order to acknowledge the notification.
+ */
+typedef void (*vdo_read_only_notification_fn)(void *listener, struct vdo_completion *parent);
+
+/*
+ * An object to be notified when the VDO enters read-only mode
+ */
+struct read_only_listener {
+	/* The listener */
+	void *listener;
+	/* The method to call to notify the listener */
+	vdo_read_only_notification_fn notify;
+	/* A pointer to the next listener */
+	struct read_only_listener *next;
+};
+
+struct vdo_thread {
+	struct vdo *vdo;
+	thread_id_t thread_id;
+	struct vdo_work_queue *queue;
+	/*
+	 * Each thread maintains its own notion of whether the VDO is read-only so that the
+	 * read-only state can be checked from any base thread without worrying about
+	 * synchronization or thread safety. This does mean that knowledge of the VDO going
+	 * read-only does not occur simultaneously across the VDO's threads, but that does not seem
+	 * to cause any problems.
+	 */
+	bool is_read_only;
+	/*
+	 * A list of objects waiting to be notified on this thread that the VDO has entered
+	 * read-only mode.
+	 */
+	struct read_only_listener *listeners;
+	struct registered_thread allocating_thread;
+};
+
+/* Keep struct bio statistics atomically */
+struct atomic_bio_stats {
+	atomic64_t read; /* Number of not REQ_WRITE bios */
+	atomic64_t write; /* Number of REQ_WRITE bios */
+	atomic64_t discard; /* Number of REQ_DISCARD bios */
+	atomic64_t flush; /* Number of REQ_FLUSH bios */
+	atomic64_t empty_flush; /* Number of REQ_PREFLUSH bios without data */
+	atomic64_t fua; /* Number of REQ_FUA bios */
+};
+
+/* Counters are atomic since updates can arrive concurrently from arbitrary threads. */
+struct atomic_statistics {
+	atomic64_t bios_submitted;
+	atomic64_t bios_completed;
+	atomic64_t flush_out;
+	atomic64_t invalid_advice_pbn_count;
+	atomic64_t no_space_error_count;
+	atomic64_t read_only_error_count;
+	struct atomic_bio_stats bios_in;
+	struct atomic_bio_stats bios_in_partial;
+	struct atomic_bio_stats bios_out;
+	struct atomic_bio_stats bios_out_completed;
+	struct atomic_bio_stats bios_acknowledged;
+	struct atomic_bio_stats bios_acknowledged_partial;
+	struct atomic_bio_stats bios_meta;
+	struct atomic_bio_stats bios_meta_completed;
+	struct atomic_bio_stats bios_journal;
+	struct atomic_bio_stats bios_journal_completed;
+	struct atomic_bio_stats bios_page_cache;
+	struct atomic_bio_stats bios_page_cache_completed;
+};
+
+struct read_only_notifier {
+	/* The completion for entering read-only mode */
+	struct vdo_completion completion;
+	/* A completion waiting for notifications to be drained or enabled */
+	struct vdo_completion *waiter;
+	/* Lock to protect the next two fields */
+	spinlock_t lock;
+	/* The code of the error which put the VDO into read-only mode */
+	int read_only_error;
+	/* The current state of the notifier (values described above) */
+	enum notifier_state state;
+};
+
+/*
+ * The thread ID returned when the current thread is not a vdo thread, or can not be determined
+ * (usually due to being at interrupt context).
+ */
+#define VDO_INVALID_THREAD_ID ((thread_id_t) -1)
+
+struct thread_config {
+	zone_count_t logical_zone_count;
+	zone_count_t physical_zone_count;
+	zone_count_t hash_zone_count;
+	thread_count_t bio_thread_count;
+	thread_count_t thread_count;
+	thread_id_t admin_thread;
+	thread_id_t journal_thread;
+	thread_id_t packer_thread;
+	thread_id_t dedupe_thread;
+	thread_id_t bio_ack_thread;
+	thread_id_t cpu_thread;
+	thread_id_t *logical_threads;
+	thread_id_t *physical_threads;
+	thread_id_t *hash_zone_threads;
+	thread_id_t *bio_threads;
+};
+
+struct thread_count_config;
+
+struct vdo_super_block {
+	/* The vio for reading and writing the super block to disk */
+	struct vio vio;
+	/* A buffer to hold the super block */
+	u8 *buffer;
+	/* Whether this super block may not be written */
+	bool unwritable;
+};
+
+struct data_vio_pool;
+
+struct vdo_administrator {
+	struct vdo_completion completion;
+	struct admin_state state;
+	atomic_t busy;
+	u32 phase;
+	struct completion callback_sync;
+};
+
+struct vdo {
+	char thread_name_prefix[MAX_VDO_WORK_QUEUE_NAME_LEN];
+	struct vdo_thread *threads;
+	vdo_action_fn action;
+	struct vdo_completion *completion;
+	struct vio_tracer *vio_tracer;
+
+	/* The atomic version of the state of this vdo */
+	atomic_t state;
+	/* The full state of all components */
+	struct vdo_component_states states;
+	/*
+	 * A counter value to attach to thread names and log messages to identify the individual
+	 * device.
+	 */
+	unsigned int instance;
+	/* The read-only notifier */
+	struct read_only_notifier read_only_notifier;
+	/* The load-time configuration of this vdo */
+	struct device_config *device_config;
+	/* The thread mapping */
+	struct thread_config thread_config;
+
+	/* The super block */
+	struct vdo_super_block super_block;
+
+	/* The partitioning of the underlying storage */
+	struct layout layout;
+	struct layout next_layout;
+	struct dm_kcopyd_client *partition_copier;
+
+	/* The block map */
+	struct block_map *block_map;
+
+	/* The journal for block map recovery */
+	struct recovery_journal *recovery_journal;
+
+	/* The slab depot */
+	struct slab_depot *depot;
+
+	/* The compressed-block packer */
+	struct packer *packer;
+	/* Whether incoming data should be compressed */
+	bool compressing;
+
+	/* The handler for flush requests */
+	struct flusher *flusher;
+
+	/* The state the vdo was in when loaded (primarily for unit tests) */
+	enum vdo_state load_state;
+
+	/* The logical zones of this vdo */
+	struct logical_zones *logical_zones;
+
+	/* The physical zones of this vdo */
+	struct physical_zones *physical_zones;
+
+	/* The hash lock zones of this vdo */
+	struct hash_zones *hash_zones;
+
+	/* Bio submission manager used for sending bios to the storage device. */
+	struct io_submitter *io_submitter;
+
+	/* The pool of data_vios for servicing incoming bios */
+	struct data_vio_pool *data_vio_pool;
+
+	/* The manager for administrative operations */
+	struct vdo_administrator admin;
+
+	/* Flags controlling administrative operations */
+	const struct admin_state_code *suspend_type;
+	bool allocations_allowed;
+	bool dump_on_shutdown;
+	atomic_t processing_message;
+
+	/*
+	 * Statistics
+	 * Atomic stats counters
+	 */
+	struct atomic_statistics stats;
+	/* Used to gather statistics without allocating memory */
+	struct vdo_statistics stats_buffer;
+	/* Protects the stats_buffer */
+	struct mutex stats_mutex;
+
+	/* A list of all device_configs referencing this vdo */
+	struct list_head device_config_list;
+
+	/* This VDO's list entry for the device registry */
+	struct list_head registration;
+
+	/* Underlying block device info. */
+	u64 starting_sector_offset;
+	struct volume_geometry geometry;
+
+	/* N blobs of context data for LZ4 code, one per CPU thread. */
+	char **compression_context;
+};
+
+/**
+ * vdo_uses_bio_ack_queue() - Indicate whether the vdo is configured to use a separate work queue
+ *                            for acknowledging received and processed bios.
+ * @vdo: The vdo.
+ *
+ * Note that this directly controls the handling of write operations, but the compile-time flag
+ * VDO_USE_BIO_ACK_QUEUE_FOR_READ is also checked for read operations.
+ *
+ * Return: Whether a bio-acknowledgement work queue is in use.
+ */
+static inline bool vdo_uses_bio_ack_queue(struct vdo *vdo)
+{
+	return vdo->device_config->thread_counts.bio_ack_threads > 0;
+}
+
+/**
+ * typedef vdo_filter_fn - Method type for vdo matching methods.
+ *
+ * A filter function returns false if the vdo doesn't match.
+ */
+typedef bool (*vdo_filter_fn)(struct vdo *vdo, const void *context);
+
+void vdo_initialize_device_registry_once(void);
+struct vdo * __must_check vdo_find_matching(vdo_filter_fn filter, const void *context);
+
+int __must_check vdo_make_thread(struct vdo *vdo, thread_id_t thread_id,
+				 const struct vdo_work_queue_type *type,
+				 unsigned int queue_count, void *contexts[]);
+
+static inline int __must_check vdo_make_default_thread(struct vdo *vdo,
+						       thread_id_t thread_id)
+{
+	return vdo_make_thread(vdo, thread_id, NULL, 1, NULL);
+}
+
+int __must_check vdo_make(unsigned int instance, struct device_config *config,
+			  char **reason, struct vdo **vdo_ptr);
+
+void vdo_destroy(struct vdo *vdo);
+
+void vdo_load_super_block(struct vdo *vdo, struct vdo_completion *parent);
+
+struct block_device * __must_check vdo_get_backing_device(const struct vdo *vdo);
+
+const char * __must_check vdo_get_device_name(const struct dm_target *target);
+
+int __must_check vdo_synchronous_flush(struct vdo *vdo);
+
+const struct admin_state_code * __must_check vdo_get_admin_state(const struct vdo *vdo);
+
+bool vdo_set_compressing(struct vdo *vdo, bool enable);
+
+bool vdo_get_compressing(struct vdo *vdo);
+
+void vdo_fetch_statistics(struct vdo *vdo, struct vdo_statistics *stats);
+
+thread_id_t vdo_get_callback_thread_id(void);
+
+enum vdo_state __must_check vdo_get_state(const struct vdo *vdo);
+
+void vdo_set_state(struct vdo *vdo, enum vdo_state state);
+
+void vdo_save_components(struct vdo *vdo, struct vdo_completion *parent);
+
+int vdo_register_read_only_listener(struct vdo *vdo, void *listener,
+				    vdo_read_only_notification_fn notification,
+				    thread_id_t thread_id);
+
+int vdo_enable_read_only_entry(struct vdo *vdo);
+
+void vdo_wait_until_not_entering_read_only_mode(struct vdo_completion *parent);
+
+void vdo_allow_read_only_mode_entry(struct vdo_completion *parent);
+
+void vdo_enter_read_only_mode(struct vdo *vdo, int error_code);
+
+bool __must_check vdo_is_read_only(struct vdo *vdo);
+
+bool __must_check vdo_in_read_only_mode(const struct vdo *vdo);
+
+bool __must_check vdo_in_recovery_mode(const struct vdo *vdo);
+
+void vdo_enter_recovery_mode(struct vdo *vdo);
+
+void vdo_assert_on_admin_thread(const struct vdo *vdo, const char *name);
+
+void vdo_assert_on_logical_zone_thread(const struct vdo *vdo, zone_count_t logical_zone,
+				       const char *name);
+
+void vdo_assert_on_physical_zone_thread(const struct vdo *vdo, zone_count_t physical_zone,
+					const char *name);
+
+int __must_check vdo_get_physical_zone(const struct vdo *vdo, physical_block_number_t pbn,
+				       struct physical_zone **zone_ptr);
+
+void vdo_dump_status(const struct vdo *vdo);
+
+#endif /* VDO_H */