cciss: Add enhanced scatter-gather support.

cciss: Add enhanced scatter-gather support.  For controllers which
supported, more than 512 scatter-gather elements per command may
be used, and the max transfer size can be increased to 8192 blocks.

Signed-off-by: Don Brace <brace@beardog.cce.hp.com>
Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 17 insertions, 1 deletions

diff --git a/drivers/block/cciss.h b/drivers/block/cciss.h
index 31524cf42c77..e5c63e579ffc 100644
--- a/drivers/block/cciss.h
+++ b/drivers/block/cciss.h
@@ -55,7 +55,13 @@ typedef struct _drive_info_struct
         char device_initialized;     /* indicates whether dev is initialized */
 } drive_info_struct;
 
-struct ctlr_info 
+struct Cmd_sg_list {
+        SGDescriptor_struct     *sgchain;
+        dma64_addr_t            sg_chain_dma;
+        int                     chain_block_size;
+};
+
+struct ctlr_info
 {
         int     ctlr;
         char    devname[8];
@@ -75,6 +81,16 @@ struct ctlr_info
         int     num_luns;
         int     highest_lun;
         int     usage_count;  /* number of opens all all minor devices */
+        /* Need space for temp sg list
+         * number of scatter/gathers supported
+         * number of scatter/gathers in chained block
+         */
+        struct  scatterlist **scatter_list;
+        int     maxsgentries;
+        int     chainsize;
+        int     max_cmd_sgentries;
+        struct Cmd_sg_list **cmd_sg_list;
+
 #       define DOORBELL_INT     0
 #       define PERF_MODE_INT    1
 #       define SIMPLE_MODE_INT  2