[PATCH 4.14 105/167] jbd2: fix sphinx kernel-doc build warnings

Greg Kroah-Hartman
2018-02-21T12:48:36Z

From: Tobin C. Harding <me@tobin.cc>

commit f69120ce6c024aa634a8fc25787205e42f0ccbe6 upstream.

Sphinx emits various (26) warnings when building make target 'htmldocs'.
Currently struct definitions contain duplicate documentation, some as
kernel-docs and some as standard c89 comments. We can reduce
duplication while cleaning up the kernel docs.

Move all kernel-docs to right above each struct member. Use the set of
all existing comments (kernel-doc and c89). Add documentation for
missing struct members and function arguments.

Signed-off-by: Tobin C. Harding <me@tobin.cc>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/jbd2/transaction.c | 5
include/linux/jbd2.h | 431 +++++++++++++++++++++++++++++++-------------------
2 files changed, 272 insertions(+), 164 deletions(-)

--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -495,8 +495,10 @@ void jbd2_journal_free_reserved(handle_t
EXPORT_SYMBOL(jbd2_journal_free_reserved);

/**
- * int jbd2_journal_start_reserved(handle_t *handle) - start reserved handle
+ * int jbd2_journal_start_reserved() - start reserved handle
* @handle: handle to start
+ * @type: for handle statistics
+ * @line_no: for handle statistics
*
* Start handle that has been previously reserved with jbd2_journal_reserve().
* This attaches @handle to the running transaction (or creates one if there's
@@ -626,6 +628,7 @@ error_out:
* int jbd2_journal_restart() - restart a handle .
* @handle: handle to restart
* @nblocks: nr credits requested
+ * @gfp_mask: memory allocation flags (for start_this_handle)
*
* Restart a handle for a multi-transaction filesystem
* operation.
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -418,26 +418,41 @@ static inline void jbd_unlock_bh_journal
#define JI_WAIT_DATA (1 << __JI_WAIT_DATA)

/**
- * struct jbd_inode is the structure linking inodes in ordered mode
- * present in a transaction so that we can sync them during commit.
+ * struct jbd_inode - The jbd_inode type is the structure linking inodes in
+ * ordered mode present in a transaction so that we can sync them during commit.
*/
struct jbd2_inode {
- /* Which transaction does this inode belong to? Either the running
- * transaction or the committing one. [j_list_lock] */
+ /**
+ * @i_transaction:
+ *
+ * Which transaction does this inode belong to? Either the running
+ * transaction or the committing one. [j_list_lock]
+ */
transaction_t *i_transaction;

- /* Pointer to the running transaction modifying inode's data in case
- * there is already a committing transaction touching it. [j_list_lock] */
+ /**
+ * @i_next_transaction:
+ *
+ * Pointer to the running transaction modifying inode's data in case
+ * there is already a committing transaction touching it. [j_list_lock]
+ */
transaction_t *i_next_transaction;

- /* List of inodes in the i_transaction [j_list_lock] */
+ /**
+ * @i_list: List of inodes in the i_transaction [j_list_lock]
+ */
struct list_head i_list;

- /* VFS inode this inode belongs to [constant during the lifetime
- * of the structure] */
+ /**
+ * @i_vfs_inode:
+ *
+ * VFS inode this inode belongs to [constant for lifetime of structure]
+ */
struct inode *i_vfs_inode;

- /* Flags of inode [j_list_lock] */
+ /**
+ * @i_flags: Flags of inode [j_list_lock]
+ */
unsigned long i_flags;
};

@@ -447,12 +462,20 @@ struct jbd2_revoke_table_s;
* struct handle_s - The handle_s type is the concrete type associated with
* handle_t.
* @h_transaction: Which compound transaction is this update a part of?
+ * @h_journal: Which journal handle belongs to - used iff h_reserved set.
+ * @h_rsv_handle: Handle reserved for finishing the logical operation.
* @h_buffer_credits: Number of remaining buffers we are allowed to dirty.
- * @h_ref: Reference count on this handle
- * @h_err: Field for caller's use to track errors through large fs operations
- * @h_sync: flag for sync-on-close
- * @h_jdata: flag to force data journaling
- * @h_aborted: flag indicating fatal error on handle
+ * @h_ref: Reference count on this handle.
+ * @h_err: Field for caller's use to track errors through large fs operations.
+ * @h_sync: Flag for sync-on-close.
+ * @h_jdata: Flag to force data journaling.
+ * @h_reserved: Flag for handle for reserved credits.
+ * @h_aborted: Flag indicating fatal error on handle.
+ * @h_type: For handle statistics.
+ * @h_line_no: For handle statistics.
+ * @h_start_jiffies: Handle Start time.
+ * @h_requested_credits: Holds @h_buffer_credits after handle is started.
+ * @saved_alloc_context: Saved context while transaction is open.
**/

/* Docbook can't yet cope with the bit fields, but will leave the documentation
@@ -462,32 +485,23 @@ struct jbd2_revoke_table_s;
struct jbd2_journal_handle
{
union {
- /* Which compound transaction is this update a part of? */
transaction_t *h_transaction;
/* Which journal handle belongs to - used iff h_reserved set */
journal_t *h_journal;
};

- /* Handle reserved for finishing the logical operation */
handle_t *h_rsv_handle;
-
- /* Number of remaining buffers we are allowed to dirty: */
int h_buffer_credits;
-
- /* Reference count on this handle */
int h_ref;
-
- /* Field for caller's use to track errors through large fs */
- /* operations */
int h_err;

/* Flags [no locking] */
- unsigned int h_sync: 1; /* sync-on-close */
- unsigned int h_jdata: 1; /* force data journaling */
- unsigned int h_reserved: 1; /* handle with reserved credits */
- unsigned int h_aborted: 1; /* fatal error on handle */
- unsigned int h_type: 8; /* for handle statistics */
- unsigned int h_line_no: 16; /* for handle statistics */
+ unsigned int h_sync: 1;
+ unsigned int h_jdata: 1;
+ unsigned int h_reserved: 1;
+ unsigned int h_aborted: 1;
+ unsigned int h_type: 8;
+ unsigned int h_line_no: 16;

unsigned long h_start_jiffies;
unsigned int h_requested_credits;
@@ -729,228 +743,253 @@ jbd2_time_diff(unsigned long start, unsi
/**
* struct journal_s - The journal_s type is the concrete type associated with
* journal_t.
- * @j_flags: General journaling state flags
- * @j_errno: Is there an outstanding uncleared error on the journal (from a
- * prior abort)?
- * @j_sb_buffer: First part of superblock buffer
- * @j_superblock: Second part of superblock buffer
- * @j_format_version: Version of the superblock format
- * @j_state_lock: Protect the various scalars in the journal
- * @j_barrier_count: Number of processes waiting to create a barrier lock
- * @j_barrier: The barrier lock itself
- * @j_running_transaction: The current running transaction..
- * @j_committing_transaction: the transaction we are pushing to disk
- * @j_checkpoint_transactions: a linked circular list of all transactions
- * waiting for checkpointing
- * @j_wait_transaction_locked: Wait queue for waiting for a locked transaction
- * to start committing, or for a barrier lock to be released
- * @j_wait_done_commit: Wait queue for waiting for commit to complete
- * @j_wait_commit: Wait queue to trigger commit
- * @j_wait_updates: Wait queue to wait for updates to complete
- * @j_wait_reserved: Wait queue to wait for reserved buffer credits to drop
- * @j_checkpoint_mutex: Mutex for locking against concurrent checkpoints
- * @j_head: Journal head - identifies the first unused block in the journal
- * @j_tail: Journal tail - identifies the oldest still-used block in the
- * journal.
- * @j_free: Journal free - how many free blocks are there in the journal?
- * @j_first: The block number of the first usable block
- * @j_last: The block number one beyond the last usable block
- * @j_dev: Device where we store the journal
- * @j_blocksize: blocksize for the location where we store the journal.
- * @j_blk_offset: starting block offset for into the device where we store the
- * journal
- * @j_fs_dev: Device which holds the client fs. For internal journal this will
- * be equal to j_dev
- * @j_reserved_credits: Number of buffers reserved from the running transaction
- * @j_maxlen: Total maximum capacity of the journal region on disk.
- * @j_list_lock: Protects the buffer lists and internal buffer state.
- * @j_inode: Optional inode where we store the journal. If present, all journal
- * block numbers are mapped into this inode via bmap().
- * @j_tail_sequence: Sequence number of the oldest transaction in the log
- * @j_transaction_sequence: Sequence number of the next transaction to grant
- * @j_commit_sequence: Sequence number of the most recently committed
- * transaction
- * @j_commit_request: Sequence number of the most recent transaction wanting
- * commit
- * @j_uuid: Uuid of client object.
- * @j_task: Pointer to the current commit thread for this journal
- * @j_max_transaction_buffers: Maximum number of metadata buffers to allow in a
- * single compound commit transaction
- * @j_commit_interval: What is the maximum transaction lifetime before we begin
- * a commit?
- * @j_commit_timer: The timer used to wakeup the commit thread
- * @j_revoke_lock: Protect the revoke table
- * @j_revoke: The revoke table - maintains the list of revoked blocks in the
- * current transaction.
- * @j_revoke_table: alternate revoke tables for j_revoke
- * @j_wbuf: array of buffer_heads for jbd2_journal_commit_transaction
- * @j_wbufsize: maximum number of buffer_heads allowed in j_wbuf, the
- * number that will fit in j_blocksize
- * @j_last_sync_writer: most recent pid which did a synchronous write
- * @j_history_lock: Protect the transactions statistics history
- * @j_proc_entry: procfs entry for the jbd statistics directory
- * @j_stats: Overall statistics
- * @j_private: An opaque pointer to fs-private information.
- * @j_trans_commit_map: Lockdep entity to track transaction commit dependencies
*/
-
struct journal_s
{
- /* General journaling state flags [j_state_lock] */
+ /**
+ * @j_flags: General journaling state flags [j_state_lock]
+ */
unsigned long j_flags;

- /*
+ /**
+ * @j_errno:
+ *
* Is there an outstanding uncleared error on the journal (from a prior
* abort)? [j_state_lock]
*/
int j_errno;

- /* The superblock buffer */
+ /**
+ * @j_sb_buffer: The first part of the superblock buffer.
+ */
struct buffer_head *j_sb_buffer;
+
+ /**
+ * @j_superblock: The second part of the superblock buffer.
+ */
journal_superblock_t *j_superblock;

- /* Version of the superblock format */
+ /**
+ * @j_format_version: Version of the superblock format.
+ */
int j_format_version;

- /*
- * Protect the various scalars in the journal
+ /**
+ * @j_state_lock: Protect the various scalars in the journal.
*/
rwlock_t j_state_lock;

- /*
+ /**
+ * @j_barrier_count:
+ *
* Number of processes waiting to create a barrier lock [j_state_lock]
*/
int j_barrier_count;

- /* The barrier lock itself */
+ /**
+ * @j_barrier: The barrier lock itself.
+ */
struct mutex j_barrier;

- /*
+ /**
+ * @j_running_transaction:
+ *
* Transactions: The current running transaction...
* [j_state_lock] [caller holding open handle]
*/
transaction_t *j_running_transaction;

- /*
+ /**
+ * @j_committing_transaction:
+ *
* the transaction we are pushing to disk
* [j_state_lock] [caller holding open handle]
*/
transaction_t *j_committing_transaction;

- /*
+ /**
+ * @j_checkpoint_transactions:
+ *
* ... and a linked circular list of all transactions waiting for
* checkpointing. [j_list_lock]
*/
transaction_t *j_checkpoint_transactions;

- /*
+ /**
+ * @j_wait_transaction_locked:
+ *
* Wait queue for waiting for a locked transaction to start committing,
- * or for a barrier lock to be released
+ * or for a barrier lock to be released.
*/
wait_queue_head_t j_wait_transaction_locked;

- /* Wait queue for waiting for commit to complete */
+ /**
+ * @j_wait_done_commit: Wait queue for waiting for commit to complete.
+ */
wait_queue_head_t j_wait_done_commit;

- /* Wait queue to trigger commit */
+ /**
+ * @j_wait_commit: Wait queue to trigger commit.
+ */
wait_queue_head_t j_wait_commit;

- /* Wait queue to wait for updates to complete */
+ /**
+ * @j_wait_updates: Wait queue to wait for updates to complete.
+ */
wait_queue_head_t j_wait_updates;

- /* Wait queue to wait for reserved buffer credits to drop */
+ /**
+ * @j_wait_reserved:
+ *
+ * Wait queue to wait for reserved buffer credits to drop.
+ */
wait_queue_head_t j_wait_reserved;

- /* Semaphore for locking against concurrent checkpoints */
+ /**
+ * @j_checkpoint_mutex:
+ *
+ * Semaphore for locking against concurrent checkpoints.
+ */
struct mutex j_checkpoint_mutex;

- /*
+ /**
+ * @j_chkpt_bhs:
+ *
* List of buffer heads used by the checkpoint routine. This
* was moved from jbd2_log_do_checkpoint() to reduce stack
* usage. Access to this array is controlled by the
- * j_checkpoint_mutex. [j_checkpoint_mutex]
+ * @j_checkpoint_mutex. [j_checkpoint_mutex]
*/
struct buffer_head *j_chkpt_bhs[JBD2_NR_BATCH];
-
- /*
+
+ /**
+ * @j_head:
+ *
* Journal head: identifies the first unused block in the journal.
* [j_state_lock]
*/
unsigned long j_head;

- /*
+ /**
+ * @j_tail:
+ *
* Journal tail: identifies the oldest still-used block in the journal.
* [j_state_lock]
*/
unsigned long j_tail;

- /*
+ /**
+ * @j_free:
+ *
* Journal free: how many free blocks are there in the journal?
* [j_state_lock]
*/
unsigned long j_free;

- /*
- * Journal start and end: the block numbers of the first usable block
- * and one beyond the last usable block in the journal. [j_state_lock]
+ /**
+ * @j_first:
+ *
+ * The block number of the first usable block in the journal
+ * [j_state_lock].
*/
unsigned long j_first;
+
+ /**
+ * @j_last:
+ *
+ * The block number one beyond the last usable block in the journal
+ * [j_state_lock].
+ */
unsigned long j_last;

- /*
- * Device, blocksize and starting block offset for the location where we
- * store the journal.
+ /**
+ * @j_dev: Device where we store the journal.
*/
struct block_device *j_dev;
+
+ /**
+ * @j_blocksize: Block size for the location where we store the journal.
+ */
int j_blocksize;
+
+ /**
+ * @j_blk_offset:
+ *
+ * Starting block offset into the device where we store the journal.
+ */
unsigned long long j_blk_offset;
+
+ /**
+ * @j_devname: Journal device name.
+ */
char j_devname[BDEVNAME_SIZE+24];

- /*
+ /**
+ * @j_fs_dev:
+ *
* Device which holds the client fs. For internal journal this will be
* equal to j_dev.
*/
struct block_device *j_fs_dev;

- /* Total maximum capacity of the journal region on disk. */
+ /**
+ * @j_maxlen: Total maximum capacity of the journal region on disk.
+ */
unsigned int j_maxlen;

- /* Number of buffers reserved from the running transaction */
+ /**
+ * @j_reserved_credits:
+ *
+ * Number of buffers reserved from the running transaction.
+ */
atomic_t j_reserved_credits;

- /*
- * Protects the buffer lists and internal buffer state.
+ /**
+ * @j_list_lock: Protects the buffer lists and internal buffer state.
*/
spinlock_t j_list_lock;

- /* Optional inode where we store the journal. If present, all */
- /* journal block numbers are mapped into this inode via */
- /* bmap(). */
+ /**
+ * @j_inode:
+ *
+ * Optional inode where we store the journal. If present, all
+ * journal block numbers are mapped into this inode via bmap().
+ */
struct inode *j_inode;

- /*
+ /**
+ * @j_tail_sequence:
+ *
* Sequence number of the oldest transaction in the log [j_state_lock]
*/
tid_t j_tail_sequence;

- /*
+ /**
+ * @j_transaction_sequence:
+ *
* Sequence number of the next transaction to grant [j_state_lock]
*/
tid_t j_transaction_sequence;

- /*
+ /**
+ * @j_commit_sequence:
+ *
* Sequence number of the most recently committed transaction
* [j_state_lock].
*/
tid_t j_commit_sequence;

- /*
+ /**
+ * @j_commit_request:
+ *
* Sequence number of the most recent transaction wanting commit
* [j_state_lock]
*/
tid_t j_commit_request;

- /*
+ /**
+ * @j_uuid:
+ *
* Journal uuid: identifies the object (filesystem, LVM volume etc)
* backed by this journal. This will eventually be replaced by an array
* of uuids, allowing us to index multiple devices within a single
@@ -958,85 +997,151 @@ struct journal_s
*/
__u8 j_uuid[16];

- /* Pointer to the current commit thread for this journal */
+ /**
+ * @j_task: Pointer to the current commit thread for this journal.
+ */
struct task_struct *j_task;

- /*
+ /**
+ * @j_max_transaction_buffers:
+ *
* Maximum number of metadata buffers to allow in a single compound
- * commit transaction
+ * commit transaction.
*/
int j_max_transaction_buffers;

- /*
+ /**
+ * @j_commit_interval:
+ *
* What is the maximum transaction lifetime before we begin a commit?
*/
unsigned long j_commit_interval;

- /* The timer used to wakeup the commit thread: */
+ /**
+ * @j_commit_timer: The timer used to wakeup the commit thread.
+ */
struct timer_list j_commit_timer;

- /*
- * The revoke table: maintains the list of revoked blocks in the
- * current transaction. [j_revoke_lock]
+ /**
+ * @j_revoke_lock: Protect the revoke table.
*/
spinlock_t j_revoke_lock;
+
+ /**
+ * @j_revoke:
+ *
+ * The revoke table - maintains the list of revoked blocks in the
+ * current transaction.
+ */
struct jbd2_revoke_table_s *j_revoke;
+
+ /**
+ * @j_revoke_table: Alternate revoke tables for j_revoke.
+ */
struct jbd2_revoke_table_s *j_revoke_table[2];

- /*
- * array of bhs for jbd2_journal_commit_transaction
+ /**
+ * @j_wbuf: Array of bhs for jbd2_journal_commit_transaction.
*/
struct buffer_head **j_wbuf;
+
+ /**
+ * @j_wbufsize:
+ *
+ * Size of @j_wbuf array.
+ */
int j_wbufsize;

- /*
- * this is the pid of hte last person to run a synchronous operation
- * through the journal
+ /**
+ * @j_last_sync_writer:
+ *
+ * The pid of the last person to run a synchronous operation
+ * through the journal.
*/
pid_t j_last_sync_writer;

- /*
- * the average amount of time in nanoseconds it takes to commit a
+ /**
+ * @j_average_commit_time:
+ *
+ * The average amount of time in nanoseconds it takes to commit a
* transaction to disk. [j_state_lock]
*/
u64 j_average_commit_time;

- /*
- * minimum and maximum times that we should wait for
- * additional filesystem operations to get batched into a
- * synchronous handle in microseconds
+ /**
+ * @j_min_batch_time:
+ *
+ * Minimum time that we should wait for additional filesystem operations
+ * to get batched into a synchronous handle in microseconds.
*/
u32 j_min_batch_time;
+
+ /**
+ * @j_max_batch_time:
+ *
+ * Maximum time that we should wait for additional filesystem operations
+ * to get batched into a synchronous handle in microseconds.
+ */
u32 j_max_batch_time;

- /* This function is called when a transaction is closed */
+ /**
+ * @j_commit_callback:
+ *
+ * This function is called when a transaction is closed.
+ */
void (*j_commit_callback)(journal_t *,
transaction_t *);

/*
* Journal statistics
*/
+
+ /**
+ * @j_history_lock: Protect the transactions statistics history.
+ */
spinlock_t j_history_lock;
+
+ /**
+ * @j_proc_entry: procfs entry for the jbd statistics directory.
+ */
struct proc_dir_entry *j_proc_entry;
+
+ /**
+ * @j_stats: Overall statistics.
+ */
struct transaction_stats_s j_stats;

- /* Failed journal commit ID */
+ /**
+ * @j_failed_commit: Failed journal commit ID.
+ */
unsigned int j_failed_commit;

- /*
+ /**
+ * @j_private:
+ *
* An opaque pointer to fs-private information. ext3 puts its
- * superblock pointer here
+ * superblock pointer here.
*/
void *j_private;

- /* Reference to checksum algorithm driver via cryptoapi */
+ /**
+ * @j_chksum_driver:
+ *
+ * Reference to checksum algorithm driver via cryptoapi.
+ */
struct crypto_shash *j_chksum_driver;

- /* Precomputed journal UUID checksum for seeding other checksums */
+ /**
+ * @j_csum_seed:
+ *
+ * Precomputed journal UUID checksum for seeding other checksums.
+ */
__u32 j_csum_seed;

#ifdef CONFIG_DEBUG_LOCK_ALLOC
- /*
+ /**
+ * @j_trans_commit_map:
+ *
* Lockdep entity to track transaction commit dependencies. Handles
* hold this "lock" for read, when we wait for commit, we acquire the
* "lock" for writing. This matches the properties of jbd2 journalling