target: Move passthrough CDB parsing into a common function

Aside from whether they handle BIDI ops or not, parsing of the CDB by
kernel and user SCSI passthrough modules should be identical. Move this
into a new passthrough_parse_cdb() and call it from tcm-pscsi and tcm-user.
Reported-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ilias Tsitsimpis <iliastsi@arrikto.com>
Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/target_core_device.c

@@ -33,6 +33,7 @@
 #include <linux/kthread.h>
 #include <linux/in.h>
 #include <linux/export.h>
+#include <asm/unaligned.h>
 #include <net/sock.h>
 #include <net/tcp.h>
 #include <scsi/scsi.h>
@@ -1707,3 +1708,76 @@ void core_dev_release_virtual_lun0(void)
 		target_free_device(g_lun0_dev);
 	core_delete_hba(hba);
 }
+
+/*
+ * Common CDB parsing for kernel and user passthrough.
+ */
+sense_reason_t
+passthrough_parse_cdb(struct se_cmd *cmd,
+	sense_reason_t (*exec_cmd)(struct se_cmd *cmd))
+{
+	unsigned char *cdb = cmd->t_task_cdb;
+
+	/*
+	 * Clear a lun set in the cdb if the initiator talking to use spoke
+	 * and old standards version, as we can't assume the underlying device
+	 * won't choke up on it.
+	 */
+	switch (cdb[0]) {
+	case READ_10: /* SBC - RDProtect */
+	case READ_12: /* SBC - RDProtect */
+	case READ_16: /* SBC - RDProtect */
+	case SEND_DIAGNOSTIC: /* SPC - SELF-TEST Code */
+	case VERIFY: /* SBC - VRProtect */
+	case VERIFY_16: /* SBC - VRProtect */
+	case WRITE_VERIFY: /* SBC - VRProtect */
+	case WRITE_VERIFY_12: /* SBC - VRProtect */
+	case MAINTENANCE_IN: /* SPC - Parameter Data Format for SA RTPG */
+		break;
+	default:
+		cdb[1] &= 0x1f; /* clear logical unit number */
+		break;
+	}
+
+	/*
+	 * For REPORT LUNS we always need to emulate the response, for everything
+	 * else, pass it up.
+	 */
+	if (cdb[0] == REPORT_LUNS) {
+		cmd->execute_cmd = spc_emulate_report_luns;
+		return TCM_NO_SENSE;
+	}
+
+	/* Set DATA_CDB flag for ops that should have it */
+	switch (cdb[0]) {
+	case READ_6:
+	case READ_10:
+	case READ_12:
+	case READ_16:
+	case WRITE_6:
+	case WRITE_10:
+	case WRITE_12:
+	case WRITE_16:
+	case WRITE_VERIFY:
+	case WRITE_VERIFY_12:
+	case 0x8e: /* WRITE_VERIFY_16 */
+	case COMPARE_AND_WRITE:
+	case XDWRITEREAD_10:
+		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+		break;
+	case VARIABLE_LENGTH_CMD:
+		switch (get_unaligned_be16(&cdb[8])) {
+		case READ_32:
+		case WRITE_32:
+		case 0x0c: /* WRITE_VERIFY_32 */
+		case XDWRITEREAD_32:
+			cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+			break;
+		}
+	}
+
+	cmd->execute_cmd = exec_cmd;
+
+	return TCM_NO_SENSE;
+}
+EXPORT_SYMBOL(passthrough_parse_cdb);

drivers/target/target_core_pscsi.c

@@ -973,64 +973,13 @@ pscsi_map_sg(struct se_cmd *cmd, struct scatterlist *sgl, u32 sgl_nents,
 	return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
 }
 
-/*
- * Clear a lun set in the cdb if the initiator talking to use spoke
- * and old standards version, as we can't assume the underlying device
- * won't choke up on it.
- */
-static inline void pscsi_clear_cdb_lun(unsigned char *cdb)
-{
-	switch (cdb[0]) {
-	case READ_10: /* SBC - RDProtect */
-	case READ_12: /* SBC - RDProtect */
-	case READ_16: /* SBC - RDProtect */
-	case SEND_DIAGNOSTIC: /* SPC - SELF-TEST Code */
-	case VERIFY: /* SBC - VRProtect */
-	case VERIFY_16: /* SBC - VRProtect */
-	case WRITE_VERIFY: /* SBC - VRProtect */
-	case WRITE_VERIFY_12: /* SBC - VRProtect */
-	case MAINTENANCE_IN: /* SPC - Parameter Data Format for SA RTPG */
-		break;
-	default:
-		cdb[1] &= 0x1f; /* clear logical unit number */
-		break;
-	}
-}
-
 static sense_reason_t
 pscsi_parse_cdb(struct se_cmd *cmd)
 {
-	unsigned char *cdb = cmd->t_task_cdb;
-
 	if (cmd->se_cmd_flags & SCF_BIDI)
 		return TCM_UNSUPPORTED_SCSI_OPCODE;
 
-	pscsi_clear_cdb_lun(cdb);
-
-	/*
-	 * For REPORT LUNS we always need to emulate the response, for everything
-	 * else the default for pSCSI is to pass the command to the underlying
-	 * LLD / physical hardware.
-	 */
-	switch (cdb[0]) {
-	case REPORT_LUNS:
-		cmd->execute_cmd = spc_emulate_report_luns;
-		return 0;
-	case READ_6:
-	case READ_10:
-	case READ_12:
-	case READ_16:
-	case WRITE_6:
-	case WRITE_10:
-	case WRITE_12:
-	case WRITE_16:
-	case WRITE_VERIFY:
-		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
-		/* FALLTHROUGH*/
-	default:
-		cmd->execute_cmd = pscsi_execute_cmd;
-		return 0;
-	}
+	return passthrough_parse_cdb(cmd, pscsi_execute_cmd);
 }
 
 static sense_reason_t

drivers/target/target_core_user.c

@@ -1049,48 +1049,7 @@ tcmu_pass_op(struct se_cmd *se_cmd)
 static sense_reason_t
 tcmu_parse_cdb(struct se_cmd *cmd)
 {
-	unsigned char *cdb = cmd->t_task_cdb;
-
-	/*
-	 * For REPORT LUNS we always need to emulate the response, for everything
-	 * else, pass it up.
-	 */
-	if (cdb[0] == REPORT_LUNS) {
-		cmd->execute_cmd = spc_emulate_report_luns;
-		return TCM_NO_SENSE;
-	}
-
-	/* Set DATA_CDB flag for ops that should have it */
-	switch (cdb[0]) {
-	case READ_6:
-	case READ_10:
-	case READ_12:
-	case READ_16:
-	case WRITE_6:
-	case WRITE_10:
-	case WRITE_12:
-	case WRITE_16:
-	case WRITE_VERIFY:
-	case WRITE_VERIFY_12:
-	case 0x8e: /* WRITE_VERIFY_16 */
-	case COMPARE_AND_WRITE:
-	case XDWRITEREAD_10:
-		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
-		break;
-	case VARIABLE_LENGTH_CMD:
-		switch (get_unaligned_be16(&cdb[8])) {
-		case READ_32:
-		case WRITE_32:
-		case 0x0c: /* WRITE_VERIFY_32 */
-		case XDWRITEREAD_32:
-			cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
-			break;
-		}
-	}
-
-	cmd->execute_cmd = tcmu_pass_op;
-
-	return TCM_NO_SENSE;
+	return passthrough_parse_cdb(cmd, tcmu_pass_op);
 }
 
 DEF_TB_DEV_ATTRIB_RO(tcmu, hw_pi_prot_type);

include/target/target_core_backend.h

@@ -138,5 +138,7 @@ int	se_dev_set_queue_depth(struct se_device *, u32);
 int	se_dev_set_max_sectors(struct se_device *, u32);
 int	se_dev_set_optimal_sectors(struct se_device *, u32);
 int	se_dev_set_block_size(struct se_device *, u32);
+sense_reason_t passthrough_parse_cdb(struct se_cmd *cmd,
+	sense_reason_t (*exec_cmd)(struct se_cmd *cmd));
 
 #endif /* TARGET_CORE_BACKEND_H */