scsi: iscsi: Stop using the SCSI pointer

Instead of storing the iSCSI task pointer and the session age in the SCSI
pointer, use command-private variables. This patch prepares for removal of
the SCSI pointer from struct scsi_cmnd.

The list of iSCSI drivers has been obtained as follows:
$ git grep -lw iscsi_host_alloc
drivers/infiniband/ulp/iser/iscsi_iser.c
drivers/scsi/be2iscsi/be_main.c
drivers/scsi/bnx2i/bnx2i_iscsi.c
drivers/scsi/cxgbi/libcxgbi.c
drivers/scsi/iscsi_tcp.c
drivers/scsi/libiscsi.c
drivers/scsi/qedi/qedi_main.c
drivers/scsi/qla4xxx/ql4_os.c
include/scsi/libiscsi.h

Note: it is not clear to me how the qla4xxx driver can work without this
patch since it uses the scsi_cmnd::SCp.ptr member for two different
purposes:
- The qla4xxx driver uses this member to store a struct srb pointer.
- libiscsi uses this member to store a struct iscsi_task pointer.

Reviewed-by: Lee Duncan <lduncan@suse.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Cc: Chris Leech <cleech@redhat.com>
Cc: Sagi Grimberg <sagi@grimberg.me>
Cc: Nilesh Javali <njavali@marvell.com>
Cc: Manish Rangankar <mrangankar@marvell.com>
Cc: Karen Xie <kxie@chelsio.com>
Cc: Ketan Mukadam <ketan.mukadam@broadcom.com>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>

iscsi

Link: https://lore.kernel.org/r/20220218195117.25689-26-bvanassche@acm.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

1 files changed, 13 insertions, 3 deletions

diff --git a/drivers/scsi/qla4xxx/ql4_def.h b/drivers/scsi/qla4xxx/ql4_def.h
index 69a590546bf9..5f82c8afd5e0 100644
--- a/drivers/scsi/qla4xxx/ql4_def.h
+++ b/drivers/scsi/qla4xxx/ql4_def.h
@@ -216,11 +216,21 @@
 #define IDC_COMP_TOV			5
 #define LINK_UP_COMP_TOV		30
 
-#define CMD_SP(Cmnd)			((Cmnd)->SCp.ptr)
+/*
+ * Note: the data structure below does not have a struct iscsi_cmd member since
+ * the qla4xxx driver does not use libiscsi for SCSI I/O.
+ */
+struct qla4xxx_cmd_priv {
+	struct srb *srb;
+};
+
+static inline struct qla4xxx_cmd_priv *qla4xxx_cmd_priv(struct scsi_cmnd *cmd)
+{
+	return scsi_cmd_priv(cmd);
+}
 
 /*
- * SCSI Request Block structure	 (srb)	that is placed
- * on cmd->SCp location of every I/O	 [We have 22 bytes available]
+ * SCSI Request Block structure (srb) that is associated with each scsi_cmnd.
  */
 struct srb {
 	struct list_head list;	/* (8)	 */