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>

3 files changed, 49 insertions, 64 deletions

diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index 94c838dcfc3..71c96ce9287 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -403,64 +403,10 @@ struct se_queue_obj {
 	wait_queue_head_t	thread_wq;
 } ____cacheline_aligned;
 
-/*
- * Used one per struct se_cmd to hold all extra struct se_task
- * metadata.  This structure is setup and allocated in
- * drivers/target/target_core_transport.c:__transport_alloc_se_cmd()
- */
-struct se_transport_task {
-	unsigned char		*t_task_cdb;
-	unsigned char		__t_task_cdb[TCM_MAX_COMMAND_SIZE];
-	unsigned long long	t_task_lba;
-	int			t_tasks_failed;
-	int			t_tasks_fua;
-	bool			t_tasks_bidi;
-	u32			t_task_cdbs;
-	u32			t_tasks_check;
-	u32			t_tasks_no;
-	u32			t_tasks_sectors;
-	u32			t_tasks_se_num;
-	u32			t_tasks_se_bidi_num;
-	u32			t_tasks_sg_chained_no;
-	atomic_t		t_fe_count;
-	atomic_t		t_se_count;
-	atomic_t		t_task_cdbs_left;
-	atomic_t		t_task_cdbs_ex_left;
-	atomic_t		t_task_cdbs_timeout_left;
-	atomic_t		t_task_cdbs_sent;
-	atomic_t		t_transport_aborted;
-	atomic_t		t_transport_active;
-	atomic_t		t_transport_complete;
-	atomic_t		t_transport_queue_active;
-	atomic_t		t_transport_sent;
-	atomic_t		t_transport_stop;
-	atomic_t		t_transport_timeout;
-	atomic_t		transport_dev_active;
-	atomic_t		transport_lun_active;
-	atomic_t		transport_lun_fe_stop;
-	atomic_t		transport_lun_stop;
-	spinlock_t		t_state_lock;
-	struct completion	t_transport_stop_comp;
-	struct completion	transport_lun_fe_stop_comp;
-	struct completion	transport_lun_stop_comp;
-	struct scatterlist	*t_tasks_sg_chained;
-	struct scatterlist	t_tasks_sg_bounce;
-	void			*t_task_buf;
-	/*
-	 * Used for pre-registered fabric SGL passthrough WRITE and READ
-	 * with the special SCF_PASSTHROUGH_CONTIG_TO_SG case for TCM_Loop
-	 * and other HW target mode fabric modules.
-	 */
-	struct scatterlist	*t_task_pt_sgl;
-	struct list_head	t_mem_list;
-	/* Used for BIDI READ */
-	struct list_head	t_mem_bidi_list;
-	struct list_head	t_task_list;
-} ____cacheline_aligned;
-
 struct se_task {
 	unsigned char	task_sense;
 	struct scatterlist *task_sg;
+	u32		task_sg_num;
 	struct scatterlist *task_sg_bidi;
 	u8		task_scsi_status;
 	u8		task_flags;
@@ -471,8 +417,6 @@ struct se_task {
 	u32		task_no;
 	u32		task_sectors;
 	u32		task_size;
-	u32		task_sg_num;
-	u32		task_sg_offset;
 	enum dma_data_direction	task_data_direction;
 	struct se_cmd *task_se_cmd;
 	struct se_device	*se_dev;
@@ -534,13 +478,58 @@ struct se_cmd {
 	/* Only used for internal passthrough and legacy TCM fabric modules */
 	struct se_session	*se_sess;
 	struct se_tmr_req	*se_tmr_req;
-	struct se_transport_task t_task;
 	struct list_head	se_queue_node;
 	struct target_core_fabric_ops *se_tfo;
 	int (*transport_emulate_cdb)(struct se_cmd *);
 	void (*transport_split_cdb)(unsigned long long, u32 *, unsigned char *);
 	void (*transport_wait_for_tasks)(struct se_cmd *, int, int);
 	void (*transport_complete_callback)(struct se_cmd *);
+	unsigned char		*t_task_cdb;
+	unsigned char		__t_task_cdb[TCM_MAX_COMMAND_SIZE];
+	unsigned long long	t_task_lba;
+	int			t_tasks_failed;
+	int			t_tasks_fua;
+	bool			t_tasks_bidi;
+	u32			t_tasks_se_num;
+	u32			t_tasks_se_bidi_num;
+	u32			t_tasks_sg_chained_no;
+	atomic_t		t_fe_count;
+	atomic_t		t_se_count;
+	atomic_t		t_task_cdbs_left;
+	atomic_t		t_task_cdbs_ex_left;
+	atomic_t		t_task_cdbs_timeout_left;
+	atomic_t		t_task_cdbs_sent;
+	atomic_t		t_transport_aborted;
+	atomic_t		t_transport_active;
+	atomic_t		t_transport_complete;
+	atomic_t		t_transport_queue_active;
+	atomic_t		t_transport_sent;
+	atomic_t		t_transport_stop;
+	atomic_t		t_transport_timeout;
+	atomic_t		transport_dev_active;
+	atomic_t		transport_lun_active;
+	atomic_t		transport_lun_fe_stop;
+	atomic_t		transport_lun_stop;
+	spinlock_t		t_state_lock;
+	struct completion	t_transport_stop_comp;
+	struct completion	transport_lun_fe_stop_comp;
+	struct completion	transport_lun_stop_comp;
+	struct scatterlist	*t_tasks_sg_chained;
+	struct scatterlist	t_tasks_sg_bounce;
+	void			*t_task_buf;
+	/*
+	 * Used for pre-registered fabric SGL passthrough WRITE and READ
+	 * with the special SCF_PASSTHROUGH_CONTIG_TO_SG case for TCM_Loop
+	 * and other HW target mode fabric modules.
+	 */
+	struct scatterlist	*t_task_pt_sgl;
+	u32			t_task_pt_sgl_num;
+	struct list_head	t_mem_list;
+	/* Used for BIDI READ */
+	struct list_head	t_mem_bidi_list;
+	struct list_head	t_task_list;
+	u32			t_task_list_num;
+
 } ____cacheline_aligned;
 
 struct se_tmr_req {
diff --git a/include/target/target_core_fabric_ops.h b/include/target/target_core_fabric_ops.h
index 747e1404dca..1752ed3f77f 100644
--- a/include/target/target_core_fabric_ops.h
+++ b/include/target/target_core_fabric_ops.h
@@ -39,11 +39,6 @@ struct target_core_fabric_ops {
 	 */
 	int (*new_cmd_map)(struct se_cmd *);
 	/*
-	 * Optional function pointer for TCM fabric modules that use
-	 * Linux/NET sockets to allocate struct iovec array to struct se_cmd
-	 */
-	int (*alloc_cmd_iovecs)(struct se_cmd *);
-	/*
 	 * Optional to release struct se_cmd and fabric dependent allocated
 	 * I/O descriptor in transport_cmd_check_stop()
 	 */
diff --git a/include/target/target_core_transport.h b/include/target/target_core_transport.h
index acd59149176..c9846d52194 100644
--- a/include/target/target_core_transport.h
+++ b/include/target/target_core_transport.h
@@ -184,10 +184,11 @@ extern void transport_generic_free_cmd(struct se_cmd *, int, int, int);
 extern void transport_generic_wait_for_cmds(struct se_cmd *, int);
 extern int transport_init_task_sg(struct se_task *, struct se_mem *, u32);
 extern int transport_map_mem_to_sg(struct se_task *, struct list_head *,
-					void *, struct se_mem *,
+					struct scatterlist *, struct se_mem *,
 					struct se_mem **, u32 *, u32 *);
 extern void transport_do_task_sg_chain(struct se_cmd *);
 extern void transport_generic_process_write(struct se_cmd *);
+extern int transport_generic_new_cmd(struct se_cmd *);
 extern int transport_generic_do_tmr(struct se_cmd *);
 /* From target_core_alua.c */
 extern int core_alua_check_nonop_delay(struct se_cmd *);