target: Updates from AGrover and HCH (round 3)

This patch contains a squashed version of third round series cleanups,
improvements ,and simplfications from Andy and Christoph ahead of the
heavy lifting between round 3 -> 4 for the target core SGL conversion.

This include cleanups to the main target I/O path and other miscellaneous
updates.

target: Replace custom sg<->buf functions with lib funcs
target: Simplify sector limiting code
target: get_cdb should never return NULL
target: Simplify transport_memcpy_se_mem_read_contig
target: Use assignment rather than increment for t_task_cdbs
target: Don't pass dma_size to generic_get_mem
target: Pass sg with type scatterlist in transport_map_sg_to_mem
target: Move task_sg_num next to task_sg in struct se_task
target: inline struct se_transport_task into struct se_cmd
target: Change name & semantics of transport_get_sectors()
target: Remove unused members of se_cmd
target: Rename se_cmd.t_task_cdbs to t_task_list_num
target: Fix some spelling
target: Remove unused var from transport_generic_do_tmr
target: map_sg_to_mem: return sg_count in return value
target/pscsi: Use min_t for sector limits
target/pscsi: Unused param for pscsi_get_bio()
target: Rename get_cdb_count to allocate_tasks
target: Make transport_generic_new_cmd() available for iscsi-target
target: Remove fabric callback to allocate iovecs
target: Fix transport_generic_new_cmd WRITE comment

(hch: Use __GFP_ZERO usage for alloc_pages() usage)

Signed-off-by: Andy Grover <agrover@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/loopback/tcm_loop.c

@@ -118,7 +118,7 @@ static struct se_cmd *tcm_loop_allocate_core_cmd(
 	 * Signal BIDI usage with T_TASK(cmd)->t_tasks_bidi
 	 */
 	if (scsi_bidi_cmnd(sc))
-		se_cmd->t_task.t_tasks_bidi = 1;
+		se_cmd->t_tasks_bidi = 1;
 	/*
 	 * Locate the struct se_lun pointer and attach it to struct se_cmd
 	 */
@@ -169,7 +169,7 @@ static int tcm_loop_new_cmd_map(struct se_cmd *se_cmd)
 	 * For BIDI commands, pass in the extra READ buffer
 	 * to transport_generic_map_mem_to_cmd() below..
 	 */
-	if (se_cmd->t_task.t_tasks_bidi) {
+	if (se_cmd->t_tasks_bidi) {
 		struct scsi_data_buffer *sdb = scsi_in(sc);
 
 		sgl_bidi = sdb->table.sgl;
@@ -1423,13 +1423,6 @@ static int tcm_loop_register_configfs(void)
 	fabric->tf_ops.tpg_release_fabric_acl =
 					&tcm_loop_tpg_release_fabric_acl;
 	fabric->tf_ops.tpg_get_inst_index = &tcm_loop_get_inst_index;
-	/*
-	 * Since tcm_loop is mapping physical memory from Linux/SCSI
-	 * struct scatterlist arrays for each struct scsi_cmnd I/O,
-	 * we do not need TCM to allocate a iovec array for
-	 * virtual memory address mappings
-	 */
-	fabric->tf_ops.alloc_cmd_iovecs = NULL;
 	/*
 	 * Used for setting up remaining TCM resources in process context
 	 */

drivers/target/target_core_alua.c

@@ -65,7 +65,7 @@ int core_emulate_report_target_port_groups(struct se_cmd *cmd)
 	struct se_port *port;
 	struct t10_alua_tg_pt_gp *tg_pt_gp;
 	struct t10_alua_tg_pt_gp_member *tg_pt_gp_mem;
-	unsigned char *buf = (unsigned char *)cmd->t_task.t_task_buf;
+	unsigned char *buf = (unsigned char *)cmd->t_task_buf;
 	u32 rd_len = 0, off = 4; /* Skip over RESERVED area to first
 				    Target port group descriptor */
 
@@ -157,7 +157,7 @@ int core_emulate_set_target_port_groups(struct se_cmd *cmd)
 	struct se_node_acl *nacl = cmd->se_sess->se_node_acl;
 	struct t10_alua_tg_pt_gp *tg_pt_gp = NULL, *l_tg_pt_gp;
 	struct t10_alua_tg_pt_gp_member *tg_pt_gp_mem, *l_tg_pt_gp_mem;
-	unsigned char *buf = (unsigned char *)cmd->t_task.t_task_buf;
+	unsigned char *buf = (unsigned char *)cmd->t_task_buf;
 	unsigned char *ptr = &buf[4]; /* Skip over RESERVED area in header */
 	u32 len = 4; /* Skip over RESERVED area in header */
 	int alua_access_state, primary = 0, rc;

drivers/target/target_core_cdb.c

@@ -66,7 +66,7 @@ target_emulate_inquiry_std(struct se_cmd *cmd)
 {
 	struct se_lun *lun = cmd->se_lun;
 	struct se_device *dev = cmd->se_dev;
-	unsigned char *buf = cmd->t_task.t_task_buf;
+	unsigned char *buf = cmd->t_task_buf;
 
 	/*
 	 * Make sure we at least have 6 bytes of INQUIRY response
@@ -621,8 +621,8 @@ static int
 target_emulate_inquiry(struct se_cmd *cmd)
 {
 	struct se_device *dev = cmd->se_dev;
-	unsigned char *buf = cmd->t_task.t_task_buf;
-	unsigned char *cdb = cmd->t_task.t_task_cdb;
+	unsigned char *buf = cmd->t_task_buf;
+	unsigned char *cdb = cmd->t_task_cdb;
 
 	if (!(cdb[1] & 0x1))
 		return target_emulate_inquiry_std(cmd);
@@ -666,7 +666,7 @@ static int
 target_emulate_readcapacity(struct se_cmd *cmd)
 {
 	struct se_device *dev = cmd->se_dev;
-	unsigned char *buf = cmd->t_task.t_task_buf;
+	unsigned char *buf = cmd->t_task_buf;
 	unsigned long long blocks_long = dev->transport->get_blocks(dev);
 	u32 blocks;
 
@@ -696,7 +696,7 @@ static int
 target_emulate_readcapacity_16(struct se_cmd *cmd)
 {
 	struct se_device *dev = cmd->se_dev;
-	unsigned char *buf = cmd->t_task.t_task_buf;
+	unsigned char *buf = cmd->t_task_buf;
 	unsigned long long blocks = dev->transport->get_blocks(dev);
 
 	buf[0] = (blocks >> 56) & 0xff;
@@ -831,8 +831,8 @@ static int
 target_emulate_modesense(struct se_cmd *cmd, int ten)
 {
 	struct se_device *dev = cmd->se_dev;
-	char *cdb = cmd->t_task.t_task_cdb;
-	unsigned char *rbuf = cmd->t_task.t_task_buf;
+	char *cdb = cmd->t_task_cdb;
+	unsigned char *rbuf = cmd->t_task_buf;
 	int type = dev->transport->get_device_type(dev);
 	int offset = (ten) ? 8 : 4;
 	int length = 0;
@@ -903,8 +903,8 @@ target_emulate_modesense(struct se_cmd *cmd, int ten)
 static int
 target_emulate_request_sense(struct se_cmd *cmd)
 {
-	unsigned char *cdb = cmd->t_task.t_task_cdb;
-	unsigned char *buf = cmd->t_task.t_task_buf;
+	unsigned char *cdb = cmd->t_task_cdb;
+	unsigned char *buf = cmd->t_task_buf;
 	u8 ua_asc = 0, ua_ascq = 0;
 
 	if (cdb[1] & 0x01) {
@@ -965,8 +965,8 @@ target_emulate_unmap(struct se_task *task)
 {
 	struct se_cmd *cmd = task->task_se_cmd;
 	struct se_device *dev = cmd->se_dev;
-	unsigned char *buf = cmd->t_task.t_task_buf, *ptr = NULL;
-	unsigned char *cdb = &cmd->t_task.t_task_cdb[0];
+	unsigned char *buf = cmd->t_task_buf, *ptr = NULL;
+	unsigned char *cdb = &cmd->t_task_cdb[0];
 	sector_t lba;
 	unsigned int size = cmd->data_length, range;
 	int ret, offset;
@@ -1012,7 +1012,8 @@ target_emulate_write_same(struct se_task *task, int write_same32)
 {
 	struct se_cmd *cmd = task->task_se_cmd;
 	struct se_device *dev = cmd->se_dev;
-	sector_t range, lba = cmd->t_task.t_task_lba;
+	sector_t range;
+	sector_t lba = cmd->t_task_lba;
 	unsigned int num_blocks;
 	int ret;
 	/*
@@ -1021,9 +1022,9 @@ target_emulate_write_same(struct se_task *task, int write_same32)
 	 * range based on ->get_blocks() - starting LBA.
 	 */
 	if (write_same32)
-		num_blocks = get_unaligned_be32(&cmd->t_task.t_task_cdb[28]);
+		num_blocks = get_unaligned_be32(&cmd->t_task_cdb[28]);
 	else
-		num_blocks = get_unaligned_be32(&cmd->t_task.t_task_cdb[10]);
+		num_blocks = get_unaligned_be32(&cmd->t_task_cdb[10]);
 
 	if (num_blocks != 0)
 		range = num_blocks;
@@ -1052,7 +1053,7 @@ transport_emulate_control_cdb(struct se_task *task)
 	unsigned short service_action;
 	int ret = 0;
 
-	switch (cmd->t_task.t_task_cdb[0]) {
+	switch (cmd->t_task_cdb[0]) {
 	case INQUIRY:
 		ret = target_emulate_inquiry(cmd);
 		break;
@@ -1066,13 +1067,13 @@ transport_emulate_control_cdb(struct se_task *task)
 		ret = target_emulate_modesense(cmd, 1);
 		break;
 	case SERVICE_ACTION_IN:
-		switch (cmd->t_task.t_task_cdb[1] & 0x1f) {
+		switch (cmd->t_task_cdb[1] & 0x1f) {
 		case SAI_READ_CAPACITY_16:
 			ret = target_emulate_readcapacity_16(cmd);
 			break;
 		default:
 			printk(KERN_ERR "Unsupported SA: 0x%02x\n",
-				cmd->t_task.t_task_cdb[1] & 0x1f);
+				cmd->t_task_cdb[1] & 0x1f);
 			return PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;
 		}
 		break;
@@ -1097,7 +1098,7 @@ transport_emulate_control_cdb(struct se_task *task)
 		break;
 	case VARIABLE_LENGTH_CMD:
 		service_action =
-			get_unaligned_be16(&cmd->t_task.t_task_cdb[8]);
+			get_unaligned_be16(&cmd->t_task_cdb[8]);
 		switch (service_action) {
 		case WRITE_SAME_32:
 			if (!dev->transport->do_discard) {
@@ -1136,7 +1137,7 @@ transport_emulate_control_cdb(struct se_task *task)
 		break;
 	default:
 		printk(KERN_ERR "Unsupported SCSI Opcode: 0x%02x for %s\n",
-			cmd->t_task.t_task_cdb[0], dev->transport->name);
+			cmd->t_task_cdb[0], dev->transport->name);
 		return PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;
 	}
 

drivers/target/target_core_device.c

@@ -168,7 +168,7 @@ int transport_lookup_cmd_lun(struct se_cmd *se_cmd, u32 unpacked_lun)
 	 */
 	spin_lock_irqsave(&se_lun->lun_cmd_lock, flags);
 	list_add_tail(&se_cmd->se_lun_node, &se_lun->lun_cmd_list);
-	atomic_set(&se_cmd->t_task.transport_lun_active, 1);
+	atomic_set(&se_cmd->transport_lun_active, 1);
 	spin_unlock_irqrestore(&se_lun->lun_cmd_lock, flags);
 
 	return 0;
@@ -656,10 +656,10 @@ int transport_core_report_lun_response(struct se_cmd *se_cmd)
 	struct se_lun *se_lun;
 	struct se_session *se_sess = se_cmd->se_sess;
 	struct se_task *se_task;
-	unsigned char *buf = se_cmd->t_task.t_task_buf;
+	unsigned char *buf = se_cmd->t_task_buf;
 	u32 cdb_offset = 0, lun_count = 0, offset = 8, i;
 
-	list_for_each_entry(se_task, &se_cmd->t_task.t_task_list, t_list)
+	list_for_each_entry(se_task, &se_cmd->t_task_list, t_list)
 		break;
 
 	if (!(se_task)) {

drivers/target/target_core_file.c

@@ -377,7 +377,7 @@ static void fd_emulate_sync_cache(struct se_task *task)
 	struct se_cmd *cmd = task->task_se_cmd;
 	struct se_device *dev = cmd->se_dev;
 	struct fd_dev *fd_dev = dev->dev_ptr;
-	int immed = (cmd->t_task.t_task_cdb[1] & 0x2);
+	int immed = (cmd->t_task_cdb[1] & 0x2);
 	loff_t start, end;
 	int ret;
 
@@ -391,11 +391,11 @@ static void fd_emulate_sync_cache(struct se_task *task)
 	/*
 	 * Determine if we will be flushing the entire device.
 	 */
-	if (cmd->t_task.t_task_lba == 0 && cmd->data_length == 0) {
+	if (cmd->t_task_lba == 0 && cmd->data_length == 0) {
 		start = 0;
 		end = LLONG_MAX;
 	} else {
-		start = cmd->t_task.t_task_lba * dev->se_sub_dev->se_dev_attrib.block_size;
+		start = cmd->t_task_lba * dev->se_sub_dev->se_dev_attrib.block_size;
 		if (cmd->data_length)
 			end = start + cmd->data_length;
 		else
@@ -475,7 +475,7 @@ static int fd_do_task(struct se_task *task)
 		if (ret > 0 &&
 		    dev->se_sub_dev->se_dev_attrib.emulate_write_cache > 0 &&
 		    dev->se_sub_dev->se_dev_attrib.emulate_fua_write > 0 &&
-		    cmd->t_task.t_tasks_fua) {
+		    cmd->t_tasks_fua) {
 			/*
 			 * We might need to be a bit smarter here
 			 * and return some sense data to let the initiator

drivers/target/target_core_iblock.c

@@ -331,7 +331,7 @@ static void iblock_emulate_sync_cache(struct se_task *task)
 {
 	struct se_cmd *cmd = task->task_se_cmd;
 	struct iblock_dev *ib_dev = cmd->se_dev->dev_ptr;
-	int immed = (cmd->t_task.t_task_cdb[1] & 0x2);
+	int immed = (cmd->t_task_cdb[1] & 0x2);
 	sector_t error_sector;
 	int ret;
 
@@ -400,7 +400,7 @@ static int iblock_do_task(struct se_task *task)
 		 */
 		if (dev->se_sub_dev->se_dev_attrib.emulate_write_cache == 0 ||
 		    (dev->se_sub_dev->se_dev_attrib.emulate_fua_write > 0 &&
-		     task->task_se_cmd->t_task.t_tasks_fua))
+		     task->task_se_cmd->t_tasks_fua))
 			rw = WRITE_FUA;
 		else
 			rw = WRITE;

drivers/target/target_core_pr.c

@@ -157,8 +157,8 @@ static int core_scsi2_reservation_reserve(struct se_cmd *cmd)
 	struct se_session *sess = cmd->se_sess;
 	struct se_portal_group *tpg = sess->se_tpg;
 
-	if ((cmd->t_task.t_task_cdb[1] & 0x01) &&
-	    (cmd->t_task.t_task_cdb[1] & 0x02)) {
+	if ((cmd->t_task_cdb[1] & 0x01) &&
+	    (cmd->t_task_cdb[1] & 0x02)) {
 		printk(KERN_ERR "LongIO and Obselete Bits set, returning"
 				" ILLEGAL_REQUEST\n");
 		return PYX_TRANSPORT_ILLEGAL_REQUEST;
@@ -216,7 +216,7 @@ int core_scsi2_emulate_crh(struct se_cmd *cmd)
 	struct se_subsystem_dev *su_dev = cmd->se_dev->se_sub_dev;
 	struct t10_pr_registration *pr_reg;
 	struct t10_reservation *pr_tmpl = &su_dev->t10_pr;
-	unsigned char *cdb = &cmd->t_task.t_task_cdb[0];
+	unsigned char *cdb = &cmd->t_task_cdb[0];
 	int crh = (su_dev->t10_pr.res_type == SPC3_PERSISTENT_RESERVATIONS);
 	int conflict = 0;
 
@@ -1482,7 +1482,7 @@ static int core_scsi3_decode_spec_i_port(
 	struct list_head tid_dest_list;
 	struct pr_transport_id_holder *tidh_new, *tidh, *tidh_tmp;
 	struct target_core_fabric_ops *tmp_tf_ops;
-	unsigned char *buf = (unsigned char *)cmd->t_task.t_task_buf;
+	unsigned char *buf = (unsigned char *)cmd->t_task_buf;
 	unsigned char *ptr, *i_str = NULL, proto_ident, tmp_proto_ident;
 	char *iport_ptr = NULL, dest_iport[64], i_buf[PR_REG_ISID_ID_LEN];
 	u32 tpdl, tid_len = 0;
@@ -3307,7 +3307,7 @@ static int core_scsi3_emulate_pro_register_and_move(
 	struct target_core_fabric_ops *dest_tf_ops = NULL, *tf_ops;
 	struct t10_pr_registration *pr_reg, *pr_res_holder, *dest_pr_reg;
 	struct t10_reservation *pr_tmpl = &dev->se_sub_dev->t10_pr;
-	unsigned char *buf = (unsigned char *)cmd->t_task.t_task_buf;
+	unsigned char *buf = (unsigned char *)cmd->t_task_buf;
 	unsigned char *initiator_str;
 	char *iport_ptr = NULL, dest_iport[64], i_buf[PR_REG_ISID_ID_LEN];
 	u32 tid_len, tmp_tid_len;
@@ -3723,7 +3723,7 @@ static unsigned long long core_scsi3_extract_reservation_key(unsigned char *cdb)
  */
 static int core_scsi3_emulate_pr_out(struct se_cmd *cmd, unsigned char *cdb)
 {
-	unsigned char *buf = (unsigned char *)cmd->t_task.t_task_buf;
+	unsigned char *buf = (unsigned char *)cmd->t_task_buf;
 	u64 res_key, sa_res_key;
 	int sa, scope, type, aptpl;
 	int spec_i_pt = 0, all_tg_pt = 0, unreg = 0;
@@ -3830,7 +3830,7 @@ static int core_scsi3_pri_read_keys(struct se_cmd *cmd)
 	struct se_device *se_dev = cmd->se_dev;
 	struct se_subsystem_dev *su_dev = se_dev->se_sub_dev;
 	struct t10_pr_registration *pr_reg;
-	unsigned char *buf = (unsigned char *)cmd->t_task.t_task_buf;
+	unsigned char *buf = (unsigned char *)cmd->t_task_buf;
 	u32 add_len = 0, off = 8;
 
 	if (cmd->data_length < 8) {
@@ -3885,7 +3885,7 @@ static int core_scsi3_pri_read_reservation(struct se_cmd *cmd)
 	struct se_device *se_dev = cmd->se_dev;
 	struct se_subsystem_dev *su_dev = se_dev->se_sub_dev;
 	struct t10_pr_registration *pr_reg;
-	unsigned char *buf = (unsigned char *)cmd->t_task.t_task_buf;
+	unsigned char *buf = (unsigned char *)cmd->t_task_buf;
 	u64 pr_res_key;
 	u32 add_len = 16; /* Hardcoded to 16 when a reservation is held. */
 
@@ -3965,7 +3965,7 @@ static int core_scsi3_pri_report_capabilities(struct se_cmd *cmd)
 {
 	struct se_device *dev = cmd->se_dev;
 	struct t10_reservation *pr_tmpl = &dev->se_sub_dev->t10_pr;
-	unsigned char *buf = (unsigned char *)cmd->t_task.t_task_buf;
+	unsigned char *buf = (unsigned char *)cmd->t_task_buf;
 	u16 add_len = 8; /* Hardcoded to 8. */
 
 	if (cmd->data_length < 6) {
@@ -4020,7 +4020,7 @@ static int core_scsi3_pri_read_full_status(struct se_cmd *cmd)
 	struct se_portal_group *se_tpg;
 	struct t10_pr_registration *pr_reg, *pr_reg_tmp;
 	struct t10_reservation *pr_tmpl = &se_dev->se_sub_dev->t10_pr;
-	unsigned char *buf = (unsigned char *)cmd->t_task.t_task_buf;
+	unsigned char *buf = (unsigned char *)cmd->t_task_buf;
 	u32 add_desc_len = 0, add_len = 0, desc_len, exp_desc_len;
 	u32 off = 8; /* off into first Full Status descriptor */
 	int format_code = 0;
@@ -4174,7 +4174,7 @@ static int core_scsi3_emulate_pr_in(struct se_cmd *cmd, unsigned char *cdb)
 
 int core_scsi3_emulate_pr(struct se_cmd *cmd)
 {
-	unsigned char *cdb = &cmd->t_task.t_task_cdb[0];
+	unsigned char *cdb = &cmd->t_task_cdb[0];
 	struct se_device *dev = cmd->se_dev;
 	/*
 	 * Following spc2r20 5.5.1 Reservations overview: