iscsi/iser-target: Convert to command priv_size usage

This command converts iscsi/isert-target to use allocations based on
iscsit_transport->priv_size within iscsit_allocate_cmd(), instead of
using an embedded isert_cmd->iscsi_cmd.

This includes removing iscsit_transport->alloc_cmd() usage, along
with updating isert-target code to use iscsit_priv_cmd().

Also, remove left-over iscsit_transport->release_cmd() usage for
direct calls to iscsit_release_cmd(), and drop the now unused
lio_cmd_cache and isert_cmd_cache.

Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Kent Overstreet <kmo@daterainc.com>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>

drivers/infiniband/ulp/isert/ib_isert.h

@@ -67,7 +67,7 @@ struct isert_cmd {
 	u32			write_va_off;
 	u32			rdma_wr_num;
 	struct isert_conn	*conn;
-	struct iscsi_cmd	iscsi_cmd;
+	struct iscsi_cmd	*iscsi_cmd;
 	struct ib_sge		*ib_sge;
 	struct iser_tx_desc	tx_desc;
 	struct isert_rdma_wr	rdma_wr;

drivers/target/iscsi/iscsi_target.c

@@ -63,7 +63,6 @@ spinlock_t sess_idr_lock;
 
 struct iscsit_global *iscsit_global;
 
-struct kmem_cache *lio_cmd_cache;
 struct kmem_cache *lio_qr_cache;
 struct kmem_cache *lio_dr_cache;
 struct kmem_cache *lio_ooo_cache;
@@ -500,7 +499,6 @@ static struct iscsit_transport iscsi_target_transport = {
 	.iscsit_setup_np	= iscsit_setup_np,
 	.iscsit_accept_np	= iscsit_accept_np,
 	.iscsit_free_np		= iscsit_free_np,
-	.iscsit_alloc_cmd	= iscsit_alloc_cmd,
 	.iscsit_get_login_rx	= iscsit_get_login_rx,
 	.iscsit_put_login_tx	= iscsit_put_login_tx,
 	.iscsit_get_dataout	= iscsit_build_r2ts_for_cmd,
@@ -541,22 +539,13 @@ static int __init iscsi_target_init_module(void)
 		goto ts_out1;
 	}
 
-	lio_cmd_cache = kmem_cache_create("lio_cmd_cache",
-			sizeof(struct iscsi_cmd), __alignof__(struct iscsi_cmd),
-			0, NULL);
-	if (!lio_cmd_cache) {
-		pr_err("Unable to kmem_cache_create() for"
-				" lio_cmd_cache\n");
-		goto ts_out2;
-	}
-
 	lio_qr_cache = kmem_cache_create("lio_qr_cache",
 			sizeof(struct iscsi_queue_req),
 			__alignof__(struct iscsi_queue_req), 0, NULL);
 	if (!lio_qr_cache) {
 		pr_err("nable to kmem_cache_create() for"
 				" lio_qr_cache\n");
-		goto cmd_out;
+		goto ts_out2;
 	}
 
 	lio_dr_cache = kmem_cache_create("lio_dr_cache",
@@ -600,8 +589,6 @@ static int __init iscsi_target_init_module(void)
 	kmem_cache_destroy(lio_dr_cache);
 qr_out:
 	kmem_cache_destroy(lio_qr_cache);
-cmd_out:
-	kmem_cache_destroy(lio_cmd_cache);
 ts_out2:
 	iscsi_deallocate_thread_sets();
 ts_out1:
@@ -619,7 +606,6 @@ static void __exit iscsi_target_cleanup_module(void)
 	iscsi_thread_set_free();
 	iscsit_release_discovery_tpg();
 	iscsit_unregister_transport(&iscsi_target_transport);
-	kmem_cache_destroy(lio_cmd_cache);
 	kmem_cache_destroy(lio_qr_cache);
 	kmem_cache_destroy(lio_dr_cache);
 	kmem_cache_destroy(lio_ooo_cache);

drivers/target/iscsi/iscsi_target.h

@@ -39,7 +39,6 @@ extern struct target_fabric_configfs *lio_target_fabric_configfs;
 
 extern struct kmem_cache *lio_dr_cache;
 extern struct kmem_cache *lio_ooo_cache;
-extern struct kmem_cache *lio_cmd_cache;
 extern struct kmem_cache *lio_qr_cache;
 extern struct kmem_cache *lio_r2t_cache;
 

drivers/target/iscsi/iscsi_target_configfs.c

@@ -1925,7 +1925,7 @@ static void lio_release_cmd(struct se_cmd *se_cmd)
 	struct iscsi_cmd *cmd = container_of(se_cmd, struct iscsi_cmd, se_cmd);
 
 	pr_debug("Entering lio_release_cmd for se_cmd: %p\n", se_cmd);
-	cmd->release_cmd(cmd);
+	iscsit_release_cmd(cmd);
 }
 
 /* End functions for target_core_fabric_ops */

drivers/target/iscsi/iscsi_target_core.h

@@ -489,7 +489,6 @@ struct iscsi_cmd {
 	u32			first_data_sg_off;
 	u32			kmapped_nents;
 	sense_reason_t		sense_reason;
-	void (*release_cmd)(struct iscsi_cmd *);
 }  ____cacheline_aligned;
 
 struct iscsi_tmr_req {

drivers/target/iscsi/iscsi_target_util.c

@@ -149,18 +149,6 @@ void iscsit_free_r2ts_from_list(struct iscsi_cmd *cmd)
 	spin_unlock_bh(&cmd->r2t_lock);
 }
 
-struct iscsi_cmd *iscsit_alloc_cmd(struct iscsi_conn *conn, gfp_t gfp_mask)
-{
-	struct iscsi_cmd *cmd;
-
-	cmd = kmem_cache_zalloc(lio_cmd_cache, gfp_mask);
-	if (!cmd)
-		return NULL;
-
-	cmd->release_cmd = &iscsit_release_cmd;
-	return cmd;
-}
-
 /*
  * May be called from software interrupt (timer) context for allocating
  * iSCSI NopINs.
@@ -168,8 +156,9 @@ struct iscsi_cmd *iscsit_alloc_cmd(struct iscsi_conn *conn, gfp_t gfp_mask)
 struct iscsi_cmd *iscsit_allocate_cmd(struct iscsi_conn *conn, gfp_t gfp_mask)
 {
 	struct iscsi_cmd *cmd;
+	int priv_size = conn->conn_transport->priv_size;
 
-	cmd = conn->conn_transport->iscsit_alloc_cmd(conn, gfp_mask);
+	cmd = kzalloc(sizeof(struct iscsi_cmd) + priv_size, gfp_mask);
 	if (!cmd) {
 		pr_err("Unable to allocate memory for struct iscsi_cmd.\n");
 		return NULL;
@@ -696,8 +685,9 @@ void iscsit_release_cmd(struct iscsi_cmd *cmd)
 	kfree(cmd->iov_data);
 	kfree(cmd->text_in_ptr);
 
-	kmem_cache_free(lio_cmd_cache, cmd);
+	kfree(cmd);
 }
+EXPORT_SYMBOL(iscsit_release_cmd);
 
 static void __iscsit_free_cmd(struct iscsi_cmd *cmd, bool scsi_cmd,
 			      bool check_queues)
@@ -761,7 +751,7 @@ void iscsit_free_cmd(struct iscsi_cmd *cmd, bool shutdown)
 		/* Fall-through */
 	default:
 		__iscsit_free_cmd(cmd, false, shutdown);
-		cmd->release_cmd(cmd);
+		iscsit_release_cmd(cmd);
 		break;
 	}
 }

include/target/iscsi/iscsi_transport.h

@@ -6,13 +6,13 @@ struct iscsit_transport {
 #define ISCSIT_TRANSPORT_NAME	16
 	char name[ISCSIT_TRANSPORT_NAME];
 	int transport_type;
+	int priv_size;
 	struct module *owner;
 	struct list_head t_node;
 	int (*iscsit_setup_np)(struct iscsi_np *, struct __kernel_sockaddr_storage *);
 	int (*iscsit_accept_np)(struct iscsi_np *, struct iscsi_conn *);
 	void (*iscsit_free_np)(struct iscsi_np *);
 	void (*iscsit_free_conn)(struct iscsi_conn *);
-	struct iscsi_cmd *(*iscsit_alloc_cmd)(struct iscsi_conn *, gfp_t);
 	int (*iscsit_get_login_rx)(struct iscsi_conn *, struct iscsi_login *);
 	int (*iscsit_put_login_tx)(struct iscsi_conn *, struct iscsi_login *, u32);
 	int (*iscsit_immediate_queue)(struct iscsi_conn *, struct iscsi_cmd *, int);
@@ -22,6 +22,11 @@ struct iscsit_transport {
 	int (*iscsit_queue_status)(struct iscsi_conn *, struct iscsi_cmd *);
 };
 
+static inline void *iscsit_priv_cmd(struct iscsi_cmd *cmd)
+{
+	return (void *)(cmd + 1);
+}
+
 /*
  * From iscsi_target_transport.c
  */
@@ -92,3 +97,4 @@ extern int iscsit_tmr_post_handler(struct iscsi_cmd *, struct iscsi_conn *);
 extern struct iscsi_cmd *iscsit_allocate_cmd(struct iscsi_conn *, gfp_t);
 extern int iscsit_sequence_cmd(struct iscsi_conn *, struct iscsi_cmd *,
 			       unsigned char *, __be32);
+extern void iscsit_release_cmd(struct iscsi_cmd *);