bsg: split handling of SCSI CDBs vs transport requeues

The current BSG design tries to shoe-horn the transport-specific
passthrough commands into the overall framework for SCSI passthrough
requests.  This has a couple problems:

 - each passthrough queue has to set the QUEUE_FLAG_SCSI_PASSTHROUGH flag
   despite not dealing with SCSI commands at all.  Because of that these
   queues could also incorrectly accept SCSI commands from in-kernel
   users or through the legacy SCSI_IOCTL_SEND_COMMAND ioctl.
 - the real SCSI bsg queues also incorrectly accept bsg requests of the
   BSG_SUB_PROTOCOL_SCSI_TRANSPORT type
 - the bsg transport code is almost unredable because it tries to reuse
   different SCSI concepts for its own purpose.

This patch instead adds a new bsg_ops structure to handle the two cases
differently, and thus solves all of the above problems.  Another side
effect is that the bsg-lib queues also don't need to embedd a
struct scsi_request anymore.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 3 insertions, 1 deletions

diff --git a/include/linux/bsg-lib.h b/include/linux/bsg-lib.h
index 08762d297cbd..28a7ccc55c89 100644
--- a/include/linux/bsg-lib.h
+++ b/include/linux/bsg-lib.h
@@ -38,7 +38,6 @@ struct bsg_buffer {
 };
 
 struct bsg_job {
-	struct scsi_request sreq;
 	struct device *dev;
 
 	struct kref kref;
@@ -64,6 +63,9 @@ struct bsg_job {
 	struct bsg_buffer request_payload;
 	struct bsg_buffer reply_payload;
 
+	int result;
+	unsigned int reply_payload_rcv_len;
+
 	void *dd_data;		/* Used for driver-specific storage */
 };