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>

4 files changed, 78 insertions, 94 deletions

diff --git a/drivers/target/target_core_device.c b/drivers/target/target_core_device.c
index 7faa6aef9a4d..56b20dc54087 100644
--- a/drivers/target/target_core_device.c
+++ b/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);
diff --git a/drivers/target/target_core_pscsi.c b/drivers/target/target_core_pscsi.c
index 4073869d2090..53bd0eb57095 100644
--- a/drivers/target/target_core_pscsi.c
+++ b/drivers/target/target_core_pscsi.c
@@ -973,64 +973,13 @@ fail:
         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
diff --git a/drivers/target/target_core_user.c b/drivers/target/target_core_user.c
index 90e084ea7b92..2768ea2cfd7a 100644
--- a/drivers/target/target_core_user.c
+++ b/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);
diff --git a/include/target/target_core_backend.h b/include/target/target_core_backend.h
index d61be7297b2c..563e11970152 100644
--- a/include/target/target_core_backend.h
+++ b/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 */