Merge branch 'svn-trunk'

2026-05-17 10:41:26 +00:00 · 2019-08-21 17:37:12 -07:00
parent 1d5fd792a2 4aa7817dbb
commit 77b72d0901
4 changed files with 167 additions and 119 deletions
--- a/scst/src/scst_copy_mgr.c
+++ b/scst/src/scst_copy_mgr.c
@@ -2341,17 +2341,24 @@ static void scst_cm_init_inq_finish(struct scst_cmd *cmd)
 	/* cmd->dev can be NULL here! */

 	rc = scst_cm_err_check_retry(cmd, cmd->start_time, scst_cm_inq_retry_fn);
-	if (rc == SCST_CM_STATUS_RETRY || !cmd->dev || !cmd->tgt_dev)
+	if (rc == SCST_CM_STATUS_RETRY)
+		goto out;
+
+	/*
+	 * Since scst_cm_inq_retry_fn() uses cmd->tgt_i_priv, only free that
+	 * pointer once it is clear that that function won't be called.
+	 */
+	kfree(priv);
+	priv = NULL;
+	cmd->tgt_i_priv = NULL;
+
+	if (WARN_ON_ONCE(!dev))
 		goto out;

 	spin_lock_bh(&dev->dev_lock);
 	scst_unblock_dev(dev);
 	spin_unlock_bh(&dev->dev_lock);

-	kfree(priv);
-	priv = NULL;
-	cmd->tgt_i_priv = NULL;
-
 	if (rc != SCST_CM_STATUS_CMD_SUCCEEDED) {
 		PRINT_CRIT_ERROR("Unable to perform initial INQUIRY for device "
 			"%s. Copy manager for this device will be disabled",
@@ -2449,13 +2456,16 @@ out:
 static int scst_cm_send_init_inquiry(struct scst_device *dev,
 	unsigned int unpacked_lun, struct scst_cm_init_inq_priv *priv)
 {
-	int res;
+	int res = -EINVAL;
 	static const uint8_t inq_cdb[6] = { INQUIRY, 1, 0x83, 0x10, 0, 0 };
 	__be64 lun;
 	struct scst_cmd *cmd;

 	TRACE_ENTRY();

+	if (WARN_ON_ONCE(!dev))
+		goto out;
+
 	if (priv == NULL) {
 		priv = kzalloc(sizeof(*priv), GFP_KERNEL);
 		if (priv == NULL) {
@@ -2551,7 +2561,7 @@ out:

 static int scst_cm_dev_register(struct scst_device *dev, uint64_t lun)
 {
-	int res, i;
+	int res;
 	struct scst_acg_dev *acg_dev;
 	bool add_lun;

@@ -2561,27 +2571,12 @@ static int scst_cm_dev_register(struct scst_device *dev, uint64_t lun)

 	TRACE_DBG("dev %s, LUN %ld", dev->virt_name, (unsigned long)lun);

-	rcu_read_lock();
-	for (i = 0; i < SESS_TGT_DEV_LIST_HASH_SIZE; i++) {
-		struct scst_tgt_dev *tgt_dev;
-		struct list_head *head = &scst_cm_sess->sess_tgt_dev_list[i];
-
-		list_for_each_entry_rcu(tgt_dev, head,
-					sess_tgt_dev_list_entry) {
-			if (tgt_dev->dev == dev) {
-				rcu_read_unlock();
-				/*
-				 * It's OK, because the copy manager could
-				 * auto register some devices
-				 */
-				TRACE_DBG("Copy Manager already registered "
-					"device %s", dev->virt_name);
-				res = 0;
-				goto out;
-			}
-		}
+	if (scst_cm_get_lun(dev) != SCST_MAX_LUN) {
+		TRACE_DBG("Copy Manager already registered device %s",
+			  dev->virt_name);
+		res = 0;
+		goto out;
 	}
-	rcu_read_unlock();

 	if (lun == SCST_MAX_LUN) {
 		add_lun = true;
@@ -2630,9 +2625,8 @@ out_err:
 /* scst_mutex supposed to be held and activities suspended */
 static void scst_cm_dev_unregister(struct scst_device *dev, bool del_lun)
 {
-	int i;
 	struct scst_cm_desig *des, *t;
-	u32 lun = SCST_MAX_LUN;
+	u32 lun;

 	TRACE_ENTRY();

@@ -2651,21 +2645,7 @@ static void scst_cm_dev_unregister(struct scst_device *dev, bool del_lun)
 	if (!del_lun)
 		goto out;

-	rcu_read_lock();
-	for (i = 0; i < SESS_TGT_DEV_LIST_HASH_SIZE; i++) {
-		struct scst_tgt_dev *tgt_dev;
-		struct list_head *head = &scst_cm_sess->sess_tgt_dev_list[i];
-
-		list_for_each_entry_rcu(tgt_dev, head,
-					sess_tgt_dev_list_entry) {
-			if (tgt_dev->dev == dev) {
-				lun = tgt_dev->lun;
-				break;
-			}
-		}
-	}
-	rcu_read_unlock();
-
+	lun = scst_cm_get_lun(dev);
 	if (lun != SCST_MAX_LUN)
 		scst_acg_del_lun(scst_cm_tgt->default_acg, lun, false);

@@ -3726,8 +3706,9 @@ static int scst_cm_release(struct scst_tgt *tgt)

 static int scst_cm_xmit_response(struct scst_cmd *cmd)
 {
+	struct scst_icmd_priv *icmd_priv = cmd->tgt_i_priv;
+	scst_i_finish_fn_t f = icmd_priv->finish_fn;
 	int res = SCST_TGT_RES_SUCCESS;
-	scst_i_finish_fn_t f = (void *) *((unsigned long long **)cmd->tgt_i_priv);

 	TRACE_ENTRY();

--- a/scst/src/scst_lib.c
+++ b/scst/src/scst_lib.c
@@ -5843,16 +5843,31 @@ static void scst_prelim_finish_internal_cmd(struct scst_cmd *cmd)
 	return;
 }

+struct scst_request_sense_priv {
+	scst_i_finish_fn_t	finish_fn;
+	struct scst_cmd		*orig_cmd;
+};
+
+static void scst_complete_request_sense(struct scst_cmd *cmd);
+
 int scst_prepare_request_sense(struct scst_cmd *orig_cmd)
 {
-	int res = 0;
 	static const uint8_t request_sense[6] = {
 		REQUEST_SENSE, 0, 0, 0, SCST_SENSE_BUFFERSIZE, 0
 	};
+	struct scst_request_sense_priv *priv;
 	struct scst_cmd *rs_cmd;
+	int res = -ENOMEM;

 	TRACE_ENTRY();

+	priv = kzalloc(sizeof(*priv), GFP_KERNEL);
+	if (!priv)
+		goto out;
+
+	priv->finish_fn = scst_complete_request_sense;
+	priv->orig_cmd = orig_cmd;
+
 	if (orig_cmd->sense != NULL) {
 		TRACE_MEM("Releasing sense %p (orig_cmd %p)",
 			orig_cmd->sense, orig_cmd);
@@ -5864,9 +5879,9 @@ int scst_prepare_request_sense(struct scst_cmd *orig_cmd)
 			request_sense, sizeof(request_sense),
 			SCST_CMD_QUEUE_HEAD_OF_QUEUE);
 	if (rs_cmd == NULL)
-		goto out_error;
+		goto free_priv;

-	rs_cmd->tgt_i_priv = orig_cmd;
+	rs_cmd->tgt_i_priv = priv;

 	rs_cmd->cdb[1] |= scst_get_cmd_dev_d_sense(orig_cmd);
 	rs_cmd->expected_data_direction = SCST_DATA_READ;
@@ -5884,19 +5899,22 @@ out:
 	TRACE_EXIT_RES(res);
 	return res;

-out_error:
-	res = -1;
+free_priv:
+	kfree(priv);
 	goto out;
 }

 static void scst_complete_request_sense(struct scst_cmd *req_cmd)
 {
-	struct scst_cmd *orig_cmd = req_cmd->tgt_i_priv;
+	struct scst_request_sense_priv *priv = req_cmd->tgt_i_priv;
+	struct scst_cmd *orig_cmd = priv->orig_cmd;
 	uint8_t *buf;
 	int len;

 	TRACE_ENTRY();

+	kfree(priv);
+
 	sBUG_ON(orig_cmd == NULL);

 	len = scst_get_buf_full(req_cmd, &buf);
@@ -6944,8 +6962,9 @@ out_done:

 int scst_finish_internal_cmd(struct scst_cmd *cmd)
 {
-	int res;
+	struct scst_icmd_priv *icmd_priv = cmd->tgt_i_priv;
 	unsigned long flags;
+	int res;

 	TRACE_ENTRY();

@@ -6969,13 +6988,7 @@ int scst_finish_internal_cmd(struct scst_cmd *cmd)
 		scst_finish_cmd_mgmt(cmd);
 	}

-	if (cmd->cdb[0] == REQUEST_SENSE)
-		scst_complete_request_sense(cmd);
-	else {
-		scst_i_finish_fn_t f = (void *) *((unsigned long long **)cmd->tgt_i_priv);
-
-		f(cmd);
-	}
+	icmd_priv->finish_fn(cmd);

 	__scst_cmd_put(cmd);

@@ -11666,6 +11679,13 @@ static int get_cdb_info_write_same32(struct scst_cmd *cmd,
 	return get_cdb_info_write_same(cmd, sdbops, cmd->cdb[10] & 1 /*NDOB*/);
 }

+/**
+ * scst_set_cmd_from_cdb_info() - Parse the SCSI CDB.
+ * @cmd: SCSI command to parse.
+ * @ptr: Pointer to the function that will be used to parse @cmd.
+ *
+ * Return: 0 on success or >0 if the SCSI command is invalid.
+ */
 static int scst_set_cmd_from_cdb_info(struct scst_cmd *cmd,
 	const struct scst_sdbops *ptr)
 {
@@ -11955,15 +11975,18 @@ static int get_cdb_info_mo(struct scst_cmd *cmd,
 	return get_cdb_info_len_4(cmd, sdbops);
 }

-/*
- * scst_get_cdb_info() - fill various info about the command's CDB
+/**
+ * scst_get_cdb_info() - Parse the SCSI CDB according to the SCSI device type.
+ * @cmd: SCSI command to parse.
 *
 * Description:
- *    Fills various info about the command's CDB in the corresponding fields
- *    in the command.
+ *    Fill in the following fields in @cmd: cdb_len, cmd_naca,
+ *    cmd_linked, op_name, data_direction, op_flags, lba_off, lba_len,
+ *    len_off, len_len, data_direction, lba, data_len, ...
+ *    Sets SCST_LBA_NOT_VALID if the CDB has not been recognized.
 *
- *    Returns: 0 on success, <0 if command is unknown, >0 if command
- *    is invalid.
+ * Return: 0 on success, < 0 if the CDB is not recognized, > 0 if the CDB has
+ *    been recognized but is invalid.
 */
 int scst_get_cdb_info(struct scst_cmd *cmd)
 {
--- a/scst/src/scst_priv.h
+++ b/scst/src/scst_priv.h
@@ -157,6 +157,11 @@ static inline void scst_set_cmd_state(struct scst_cmd *cmd,

 typedef void (*scst_i_finish_fn_t) (struct scst_cmd *cmd);

+/* Private data associated with an internal command. */
+struct scst_icmd_priv {
+	scst_i_finish_fn_t finish_fn;
+};
+
 extern struct mutex scst_mutex2;

 extern int scst_threads;
--- a/scst/src/scst_targ.c
+++ b/scst/src/scst_targ.c
@@ -582,23 +582,23 @@ static void __scst_rx_cmd(struct scst_cmd *cmd, struct scst_session *sess,
 }

 /**
- * scst_rx_cmd_prealloced() - notify SCST that new command received
- * @cmd:	new cmd to initialized
- * @sess:	SCST session
- * @lun:	LUN for the command
- * @lun_len:	length of the LUN in bytes
- * @cdb:	CDB of the command
- * @cdb_len:	length of the CDB in bytes
- * @atomic:	true, if current context is atomic
+ * scst_rx_cmd_prealloced() - Notify SCST that a new command has been received.
+ * @cmd:	New cmd to be initialized.
+ * @sess:	SCST session.
+ * @lun:	LUN information from the SCSI transport header.
+ * @lun_len:	Length of the LUN in bytes.
+ * @cdb:	CDB of the command.
+ * @cdb_len:	Length of the CDB in bytes.
+ * @atomic:	True if called from an atomic context.
 *
- * Description:
- *    Initializes new prealloced SCST command. Returns 0 on success or
- *    negative error code otherwise.
+ *    Initializes a new preallocated SCST command.
 *
 *    Must not be called in parallel with scst_unregister_session() for the
 *    same session.
 *
 *    Cmd supposed to be zeroed!
+ *
+ * Return: 0 upon success or a negative error code otherwise.
 */
 int scst_rx_cmd_prealloced(struct scst_cmd *cmd, struct scst_session *sess,
 	const uint8_t *lun, int lun_len, const uint8_t *cdb,
@@ -632,20 +632,21 @@ out:
 EXPORT_SYMBOL(scst_rx_cmd_prealloced);

 /**
- * scst_rx_cmd() - create new command
- * @sess:	SCST session
- * @lun:	LUN for the command
- * @lun_len:	length of the LUN in bytes
- * @cdb:	CDB of the command
- * @cdb_len:	length of the CDB in bytes
- * @atomic:	true, if current context is atomic
+ * scst_rx_cmd() - Allocate a new SCSI command.
+ * @sess:	SCST session.
+ * @lun:	LUN for the command.
+ * @lun_len:	Length of the LUN in bytes.
+ * @cdb:	CDB of the commandl
+ * @cdb_len:	Length of the CDB in bytes.
+ * @atomic:	True if called from atomic context.
 *
- * Description:
- *    Creates new SCST command. Returns new command on success or
- *    NULL otherwise.
+ *    Allocates a new SCST command.
 *
 *    Must not be called in parallel with scst_unregister_session() for the
 *    same session.
+ *
+ * Return: pointer to newly allocated SCST command upon success or NULL upon
+ * failure.
 */
 struct scst_cmd *scst_rx_cmd(struct scst_session *sess,
 	const uint8_t *lun, int lun_len, const uint8_t *cdb,
@@ -680,8 +681,14 @@ out:
 }
 EXPORT_SYMBOL(scst_rx_cmd);

-/*
- * No locks, but might be on IRQ. Returns:
+/**
+ * scst_init_cmd() - ...
+ * @cmd:     SCSI command to initialize.
+ * @context: Context in which to ...
+ *
+ * No locks, but might be on IRQ.
+ *
+ * Return:
 * -  < 0 if the caller must not perform any further processing of @cmd;
 * - >= 0 if the caller must continue processing @cmd.
 */
@@ -766,29 +773,29 @@ out_redirect:
 }

 /**
- * scst_cmd_init_done() - the command's initialization done
- * @cmd:	SCST command
- * @pref_context: preferred command execution context
+ * scst_cmd_init_done() - Tells SCST to start processing a SCSI command.
+ * @cmd:	  SCST command.
+ * @pref_context: Preferred command execution context.
 *
 * Description:
- *    Notifies SCST that the driver finished its part of the command
- *    initialization, and the command is ready for execution.
- *    The second argument sets preferred command execution context.
- *    See SCST_CONTEXT_* constants for details.
+ *    Notifies SCST that the target driver finished its part of the command
+ *    initialization and also that the command is ready for execution. The
+ *    second argument sets the preferred command execution context. See also
+ *    SCST_CONTEXT_* constants for more information.
 *
 *    !!IMPORTANT!!
 *
- *    If cmd->set_sn_on_restart_cmd not set, this function, as well as
- *    scst_cmd_init_stage1_done() and scst_restart_cmd(), must not be
- *    called simultaneously for the same session (more precisely,
- *    for the same session/LUN, i.e. tgt_dev), i.e. they must be
- *    somehow externally serialized. This is needed to have lock free fast
- *    path in scst_cmd_set_sn(). For majority of targets those functions are
- *    naturally serialized by the single source of commands. Only some, like
- *    iSCSI immediate commands with multiple connections per session or
- *    scst_local, are exceptions. For it, some mutex/lock must be used for
- *    the serialization. Or, alternatively, multithreaded_init_done can
- *    be set in the target's template.
+ *    If cmd->set_sn_on_restart_cmd has not been set, this function, as well
+ *    as scst_cmd_init_stage1_done() and scst_restart_cmd(), must not be
+ *    called simultaneously for the same session (more precisely, for the same
+ *    session/LUN, i.e. tgt_dev), i.e. they must be somehow externally
+ *    serialized. This is needed to have lock free fast path in
+ *    scst_cmd_set_sn(). For majority of targets those functions are naturally
+ *    serialized by the single source of commands. Only some, like iSCSI
+ *    immediate commands with multiple connections per session or scst_local,
+ *    are exceptions. For it, some mutex/lock must be used for the
+ *    serialization. Or, alternatively, multithreaded_init_done can be set in
+ *    the target's template.
 */
 void scst_cmd_init_done(struct scst_cmd *cmd,
 	enum scst_exec_context pref_context)
@@ -921,6 +928,16 @@ out:
 }
 EXPORT_SYMBOL(scst_cmd_init_done);

+/**
+ * scst_pre_parse() - Parse the SCSI CDB.
+ * @cmd: SCSI command to parse the CDB of.
+ *
+ * Parse the SCSI CDB and call scst_set_cmd_abnormal_done_state() if the CDB
+ * has been recognized and is invalid.
+ *
+ * Return: 0 on success, < 0 if the CDB is not recognized, > 0 if the CDB has
+ *    been recognized but is invalid.
+ */
 int scst_pre_parse(struct scst_cmd *cmd)
 {
 	int res;
@@ -4979,12 +4996,19 @@ struct scst_tgt_dev *scst_lookup_tgt_dev(struct scst_session *sess, u64 lun)
 	return NULL;
 }

-/*
- * Returns 0 on success, > 0 when we need to wait for unblock,
- * < 0 if there is no device (lun) or device type handler.
+/**
+ * scst_translate_lun() - Translate @cmd->lun into a tgt_dev pointer.
+ * @cmd: SCSI command for which to translate the LUN number.
 *
- * No locks, but might be on IRQ, protection is done by the
- * suspended activity.
+ * Initialize the following @cmd members: cpu_cmd_counter, cmd_threads,
+ * tgt_dev, cur_order_data, dev and devt.
+ *
+ * The caller must not hold any locks. May be called from IRQ context. The data
+ * structures used in this function are either protected by an RCU read lock or
+ * only change while activity is suspended.
+ *
+ * Return: 0 on success, > 0 if further processing of @cmd must wait for command
+ *    processing to resume or < 0 if LUN translation failed.
 */
 static int scst_translate_lun(struct scst_cmd *cmd)
 {
@@ -5132,11 +5156,14 @@ out_bypass_aca:
 	return;
 }

-/*
+/**
+ * __scst_init_cmd() - Translate the LUN, parse the CDB and set the sequence nr.
+ * @cmd: SCSI command to initialize.
+ *
 * No locks, but might be on IRQ.
 *
- * Returns 0 on success, > 0 when we need to wait for unblock,
- * < 0 if there is no device (lun) or device type handler.
+ * Return: 0 on success, > 0 if further processing of @cmd must wait for command
+ *    processing to resume or < 0 if LUN translation failed.
 */
 static int __scst_init_cmd(struct scst_cmd *cmd)
 {
@@ -5901,7 +5928,10 @@ out:
 	return res;
 }

-/* No locks */
+/*
+ * This function is called for aborted commands before a response is sent. The
+ * caller must not hold any locks.
+ */
 void scst_done_cmd_mgmt(struct scst_cmd *cmd)
 {
 	struct scst_mgmt_cmd_stub *mstb, *t;
@@ -6057,7 +6087,10 @@ void scst_async_mcmd_completed(struct scst_mgmt_cmd *mcmd, int status)
 }
 EXPORT_SYMBOL_GPL(scst_async_mcmd_completed);

-/* No locks */
+/*
+ * This function is called for aborted commands after a response has been
+ * sent. The caller must not hold any locks.
+ */
 void scst_finish_cmd_mgmt(struct scst_cmd *cmd)
 {
 	struct scst_mgmt_cmd_stub *mstb, *t;
@@ -8251,7 +8284,7 @@ out_free:
 *			      appropriate error code otherwise
 *
 * Description:
- *    Registers new session. Returns new session on success or NULL otherwise.
+ *    Registers a new session.
 *
 *    Note: A session creation and initialization is a complex task,
 *    which requires sleeping state, so it can't be fully done
@@ -8271,6 +8304,8 @@ out_free:
 *    failed session will be returned in xmit_response() with BUSY status.
 *    In case of failure the driver shall call scst_unregister_session()
 *    inside result_fn(), it will NOT be called automatically.
+ *
+ * Return: Session pointer upon success or NULL upon failure.
 */
 struct scst_session *scst_register_session(struct scst_tgt *tgt, int atomic,
 	const char *initiator_name, void *tgt_priv, void *result_fn_data,
@@ -8301,12 +8336,14 @@ EXPORT_SYMBOL_GPL(scst_register_session);
 *			      appropriate error code otherwise.
 *
 * Description:
- *    Registers new MQ session. Returns new session on success or NULL otherwise.
+ *    Registers a new MQ session.
 *
 *    MQ session is a session, which is part of a set of sessions from the same
 *    initiator, for instance, one session per CPU. The only difference with
 *    non-MQ sessions is that reservations are not supported on MQ-sessions
 *    (because there is no way to group sessions together from reservations POV)
+ *
+ * Return: Session pointer upon success or NULL upon failure.
 */
 struct scst_session *scst_register_session_mq(struct scst_tgt *tgt, int atomic,
 	const char *initiator_name, void *tgt_priv, void *result_fn_data,
@@ -8327,7 +8364,9 @@ EXPORT_SYMBOL_GPL(scst_register_session_mq);
 * @tgt_priv:	pointer to target driver's private data
 *
 * Description:
- *    Registers new session. Returns new session on success or NULL otherwise.
+ *    Registers a new session.
+ *
+ * Return: Session pointer upon success or NULL upon failure.
 */
 struct scst_session *scst_register_session_non_gpl(struct scst_tgt *tgt,
 	const char *initiator_name, void *tgt_priv)