target: More core cleanups from AGrover (round 2)

This patch contains the squashed version of second round of target core
cleanups and simplifications and Andy and Co.   It also contains a handful
of fixes to address bugs the original series and other minor cleanups.

Here is the condensed shortlog:

target: Remove unneeded casts to void*
target: Rename get_lun_for_{cmd,tmr} to lookup_{cmd,tmr}_lun
target: Make t_task a member of se_cmd, not a pointer
target: Handle functions returning "-2"
target: Use cmd->se_dev over cmd->se_lun->lun_se_dev
target: Embed qr in struct se_cmd
target: Replace embedded struct se_queue_req with a list_head
target: Rename list_heads that are nodes in struct se_cmd to "*_node"
target: Fold transport_device_setup_cmd() into lookup_{tmr,cmd}_lun()
target: Make t_mem_list and t_mem_list_bidi members of t_task
target: Add comment & cleanup transport_map_sg_to_mem()
target: Remove unneeded checks in transport_free_pages()

(Roland: Fix se_queue_req removal leftovers OOPs)
(nab: Fix transport_lookup_tmr_lun failure case)
(nab: Fix list_empty(&cmd->t_task.t_mem_bidi_list) inversion bugs)

Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

3 files changed, 10 insertions, 12 deletions

diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index b0b83edbe453..94c838dcfc3c 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -123,7 +123,7 @@ enum se_cmd_flags_table {
         SCF_SENT_DELAYED_TAS            = 0x00020000,
         SCF_ALUA_NON_OPTIMIZED          = 0x00040000,
         SCF_DELAYED_CMD_FROM_SAM_ATTR   = 0x00080000,
-        SCF_PASSTHROUGH_SG_TO_MEM       = 0x00100000,
+        SCF_UNUSED                      = 0x00100000,
         SCF_PASSTHROUGH_CONTIG_TO_SG    = 0x00200000,
         SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC = 0x00400000,
         SCF_EMULATE_SYNC_CACHE          = 0x00800000,
@@ -452,9 +452,9 @@ struct se_transport_task {
          * and other HW target mode fabric modules.
          */
         struct scatterlist      *t_task_pt_sgl;
-        struct list_head        *t_mem_list;
+        struct list_head        t_mem_list;
         /* Used for BIDI READ */
-        struct list_head        *t_mem_bidi_list;
+        struct list_head        t_mem_bidi_list;
         struct list_head        t_task_list;
 } ____cacheline_aligned;
 
@@ -523,9 +523,9 @@ struct se_cmd {
         atomic_t                transport_sent;
         /* Used for sense data */
         void                    *sense_buffer;
-        struct list_head        se_delayed_list;
-        struct list_head        se_ordered_list;
-        struct list_head        se_lun_list;
+        struct list_head        se_delayed_node;
+        struct list_head        se_ordered_node;
+        struct list_head        se_lun_node;
         struct se_device      *se_dev;
         struct se_dev_entry   *se_deve;
         struct se_device        *se_obj_ptr;
@@ -534,9 +534,8 @@ 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;
-        /* t_task is setup to t_task_backstore in transport_init_se_cmd() */
-        struct se_transport_task *t_task;
-        struct se_transport_task t_task_backstore;
+        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 *);
diff --git a/include/target/target_core_device.h b/include/target/target_core_device.h
index d9745bfa4429..96586cc94984 100644
--- a/include/target/target_core_device.h
+++ b/include/target/target_core_device.h
@@ -1,8 +1,8 @@
 #ifndef TARGET_CORE_DEVICE_H
 #define TARGET_CORE_DEVICE_H
 
-extern int transport_get_lun_for_cmd(struct se_cmd *, u32);
-extern int transport_get_lun_for_tmr(struct se_cmd *, u32);
+extern int transport_lookup_cmd_lun(struct se_cmd *, u32);
+extern int transport_lookup_tmr_lun(struct se_cmd *, u32);
 extern struct se_dev_entry *core_get_se_deve_from_rtpi(
                                         struct se_node_acl *, u16);
 extern int core_free_device_list_for_node(struct se_node_acl *,
diff --git a/include/target/target_core_transport.h b/include/target/target_core_transport.h
index 1dd4d1841497..acd591491767 100644
--- a/include/target/target_core_transport.h
+++ b/include/target/target_core_transport.h
@@ -159,7 +159,6 @@ extern struct se_device *transport_add_device_to_core_hba(struct se_hba *,
                                         struct se_subsystem_dev *, u32,
                                         void *, struct se_dev_limits *,
                                         const char *, const char *);
-extern void transport_device_setup_cmd(struct se_cmd *);
 extern void transport_init_se_cmd(struct se_cmd *,
                                         struct target_core_fabric_ops *,
                                         struct se_session *, u32, int, int,