target: add a parse_cdb method to the backend drivers

Instead of trying to handle all SCSI command sets in one function
(transport_generic_cmd_sequencer) call out to the backend driver to perform
this functionality.  For pSCSI a copy of the existing code is used, but for
all virtual backends we can use a new parse_sbc_cdb helper is used to
provide a simple SBC emulation.

For now this setups means a fair amount of duplication between pSCSI and the
SBC library, but patches later in this series will sort out that problem.

(nab: Fix up build failure in target_core_pscsi.c)

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/target/target_core_backend.h b/include/target/target_core_backend.h
index 2d7db85e93ae..f4f1eef6bf55 100644
--- a/include/target/target_core_backend.h
+++ b/include/target/target_core_backend.h
@@ -24,6 +24,8 @@ struct se_subsystem_api {
                                 struct se_subsystem_dev *, void *);
         void (*free_device)(void *);
         int (*transport_complete)(struct se_cmd *cmd, struct scatterlist *);
+
+        int (*parse_cdb)(struct se_cmd *cmd, unsigned int *size);
         int (*execute_cmd)(struct se_cmd *, struct scatterlist *, u32,
                         enum dma_data_direction);
         int (*do_discard)(struct se_device *, sector_t, u32);
@@ -49,6 +51,9 @@ struct se_device *transport_add_device_to_core_hba(struct se_hba *,
 
 void    target_complete_cmd(struct se_cmd *, u8);
 
+int     sbc_parse_cdb(struct se_cmd *cmd, unsigned int *size);
+int     spc_parse_cdb(struct se_cmd *cmd, unsigned int *size, bool passthrough);
+
 void    transport_set_vpd_proto_id(struct t10_vpd *, unsigned char *);
 int     transport_set_vpd_assoc(struct t10_vpd *, unsigned char *);
 int     transport_set_vpd_ident_type(struct t10_vpd *, unsigned char *);