block: add bsg helper library

This moves the FC classes bsg code to the block layer and
makes it a lib so that other classes like iscsi and SAS can use it.

It is helpful because working with the request queue, bios,
creating scatterlists, etc are a pain that the LLD does not
have to worry about with normal IOs and should not have to
worry about for bsg requests.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 10 insertions, 0 deletions

diff --git a/block/Kconfig b/block/Kconfig
index 60be1e0455da..e97934eececa 100644
--- a/block/Kconfig
+++ b/block/Kconfig
@@ -65,6 +65,16 @@ config BLK_DEV_BSG
 
           If unsure, say Y.
 
+config BLK_DEV_BSGLIB
+        bool "Block layer SG support v4 helper lib"
+        default n
+        select BLK_DEV_BSG
+        help
+          Subsystems will normally enable this if needed. Users will not
+          normally need to manually enable this.
+
+          If unsure, say N.
+
 config BLK_DEV_INTEGRITY
         bool "Block layer data integrity support"
         ---help---