scsi: libfc: Stop using the SCSI pointer

Move the fc_fcp_pkt pointer, the residual length and the SCSI status into
the new data structure libfc_cmd_priv. This patch prepares for removal of
the SCSI pointer from struct scsi_cmnd.

The user of the libfc data path functions have been identified as follows:
$ git grep -lw fc_queuecommand | grep -v scsi/libfc/
drivers/scsi/fcoe/fcoe.c

Link: https://lore.kernel.org/r/20220218195117.25689-28-bvanassche@acm.org
Cc: Saurav Kashyap <skashyap@marvell.com>
Cc: Javed Hasan <jhasan@marvell.com>
Reviewed-by: Himanshu Madhani <himanshu.madhani@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/fcoe/fcoe.c

@@ -277,6 +277,7 @@ static struct scsi_host_template fcoe_shost_template = {
 	.sg_tablesize = SG_ALL,
 	.max_sectors = 0xffff,
 	.track_queue_depth = 1,
+	.cmd_size = sizeof(struct libfc_cmd_priv),
 };
 
 /**

drivers/scsi/libfc/fc_fcp.c

@@ -45,14 +45,10 @@ static struct kmem_cache *scsi_pkt_cachep;
 #define FC_SRB_READ		(1 << 1)
 #define FC_SRB_WRITE		(1 << 0)
 
-/*
- * The SCp.ptr should be tested and set under the scsi_pkt_queue lock
- */
-#define CMD_SP(Cmnd)		    ((struct fc_fcp_pkt *)(Cmnd)->SCp.ptr)
-#define CMD_ENTRY_STATUS(Cmnd)	    ((Cmnd)->SCp.have_data_in)
-#define CMD_COMPL_STATUS(Cmnd)	    ((Cmnd)->SCp.this_residual)
-#define CMD_SCSI_STATUS(Cmnd)	    ((Cmnd)->SCp.Status)
-#define CMD_RESID_LEN(Cmnd)	    ((Cmnd)->SCp.buffers_residual)
+static struct libfc_cmd_priv *libfc_priv(struct scsi_cmnd *cmd)
+{
+	return scsi_cmd_priv(cmd);
+}
 
 /**
  * struct fc_fcp_internal - FCP layer internal data
@@ -1137,7 +1133,7 @@ static int fc_fcp_pkt_send(struct fc_lport *lport, struct fc_fcp_pkt *fsp)
 	unsigned long flags;
 	int rc;
 
-	fsp->cmd->SCp.ptr = (char *)fsp;
+	libfc_priv(fsp->cmd)->fsp = fsp;
 	fsp->cdb_cmd.fc_dl = htonl(fsp->data_len);
 	fsp->cdb_cmd.fc_flags = fsp->req_flags & ~FCP_CFL_LEN_MASK;
 
@@ -1150,7 +1146,7 @@ static int fc_fcp_pkt_send(struct fc_lport *lport, struct fc_fcp_pkt *fsp)
 	rc = lport->tt.fcp_cmd_send(lport, fsp, fc_fcp_recv);
 	if (unlikely(rc)) {
 		spin_lock_irqsave(&si->scsi_queue_lock, flags);
-		fsp->cmd->SCp.ptr = NULL;
+		libfc_priv(fsp->cmd)->fsp = NULL;
 		list_del(&fsp->list);
 		spin_unlock_irqrestore(&si->scsi_queue_lock, flags);
 	}
@@ -1983,7 +1979,7 @@ static void fc_io_compl(struct fc_fcp_pkt *fsp)
 		fc_fcp_can_queue_ramp_up(lport);
 
 	sc_cmd = fsp->cmd;
-	CMD_SCSI_STATUS(sc_cmd) = fsp->cdb_status;
+	libfc_priv(sc_cmd)->status = fsp->cdb_status;
 	switch (fsp->status_code) {
 	case FC_COMPLETE:
 		if (fsp->cdb_status == 0) {
@@ -1992,7 +1988,7 @@ static void fc_io_compl(struct fc_fcp_pkt *fsp)
 			 */
 			sc_cmd->result = DID_OK << 16;
 			if (fsp->scsi_resid)
-				CMD_RESID_LEN(sc_cmd) = fsp->scsi_resid;
+				libfc_priv(sc_cmd)->resid_len = fsp->scsi_resid;
 		} else {
 			/*
 			 * transport level I/O was ok but scsi
@@ -2025,7 +2021,7 @@ static void fc_io_compl(struct fc_fcp_pkt *fsp)
 			 */
 			FC_FCP_DBG(fsp, "Returning DID_ERROR to scsi-ml "
 				   "due to FC_DATA_UNDRUN (scsi)\n");
-			CMD_RESID_LEN(sc_cmd) = fsp->scsi_resid;
+			libfc_priv(sc_cmd)->resid_len = fsp->scsi_resid;
 			sc_cmd->result = (DID_ERROR << 16) | fsp->cdb_status;
 		}
 		break;
@@ -2085,7 +2081,7 @@ static void fc_io_compl(struct fc_fcp_pkt *fsp)
 
 	spin_lock_irqsave(&si->scsi_queue_lock, flags);
 	list_del(&fsp->list);
-	sc_cmd->SCp.ptr = NULL;
+	libfc_priv(sc_cmd)->fsp = NULL;
 	spin_unlock_irqrestore(&si->scsi_queue_lock, flags);
 	scsi_done(sc_cmd);
 
@@ -2121,7 +2117,7 @@ int fc_eh_abort(struct scsi_cmnd *sc_cmd)
 
 	si = fc_get_scsi_internal(lport);
 	spin_lock_irqsave(&si->scsi_queue_lock, flags);
-	fsp = CMD_SP(sc_cmd);
+	fsp = libfc_priv(sc_cmd)->fsp;
 	if (!fsp) {
 		/* command completed while scsi eh was setting up */
 		spin_unlock_irqrestore(&si->scsi_queue_lock, flags);

include/scsi/libfc.h

@@ -351,6 +351,15 @@ struct fc_fcp_pkt {
 	struct completion tm_done;
 } ____cacheline_aligned_in_smp;
 
+/*
+ * @fsp should be tested and set under the scsi_pkt_queue lock
+ */
+struct libfc_cmd_priv {
+	struct fc_fcp_pkt *fsp;
+	u32 resid_len;
+	u8 status;
+};
+
 /*
  * Structure and function definitions for managing Fibre Channel Exchanges
  * and Sequences