[SCSI] Convert SCSI mid-layer to scsi_execute_async

Add scsi helpers to create really-large-requests and convert
scsi-ml to scsi_execute_async().

Per Jens's previous comments, I placed this function in scsi_lib.c.
I made it follow all the queue's limits - I think I did at least :), so
I removed the warning on the function header.

I think the scsi_execute_* functions should eventually take a request_queue
and be placed some place where the dm-multipath hw_handler can use them
if that failover code is going to stay in the kernel. That conversion
patch will be sent in another mail though.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 6 insertions, 0 deletions

diff --git a/include/scsi/scsi_device.h b/include/scsi/scsi_device.h
index 063e32fe036c..e94ca4d36035 100644
--- a/include/scsi/scsi_device.h
+++ b/include/scsi/scsi_device.h
@@ -274,6 +274,12 @@ extern int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
 extern int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd,
                             int data_direction, void *buffer, unsigned bufflen,
                             struct scsi_sense_hdr *, int timeout, int retries);
+extern int scsi_execute_async(struct scsi_device *sdev,
+                              const unsigned char *cmd, int data_direction,
+                              void *buffer, unsigned bufflen, int use_sg,
+                              int timeout, int retries, void *privdata,
+                              void (*done)(void *, char *, int, int),
+                              gfp_t gfp);
 
 static inline unsigned int sdev_channel(struct scsi_device *sdev)
 {