target: Add transport_reset_sgl_orig() for COMPARE_AND_WRITE

After COMPARE_AND_WRITE completes it's comparision, the WRITE
payload SGLs head expect to be updated to point from the verify
instance of user data, to the write instance of user data.

So for this special case, add transport_reset_sgl_orig() usage
within transport_free_pages() and add se_cmd->t_data_[sg,nents]_orig
members to save the original assignments.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Martin Petersen <martin.petersen@oracle.com>
Cc: Chris Mason <chris.mason@fusionio.com>
Cc: James Bottomley <JBottomley@Parallels.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Nicholas Bellinger <nab@daterainc.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
index 4a26a18a24d6..7fdb3fae2961 100644
--- a/include/target/target_core_base.h
+++ b/include/target/target_core_base.h
@@ -478,7 +478,9 @@ struct se_cmd {
         struct work_struct      work;
 
         struct scatterlist      *t_data_sg;
+        struct scatterlist      *t_data_sg_orig;
         unsigned int            t_data_nents;
+        unsigned int            t_data_nents_orig;
         void                    *t_data_vmap;
         struct scatterlist      *t_bidi_data_sg;
         unsigned int            t_bidi_data_nents;