Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 6dcfb751 authored by Konrad Rzeszutek Wilk's avatar Konrad Rzeszutek Wilk
Browse files

xen-blkfront: Provide for 'feature-flush-cache' the BLKIF_OP_WRITE_FLUSH_CACHE operation. 



The operation BLKIF_OP_WRITE_FLUSH_CACHE has existed in the Xen
tree header file for years but it was never present in the Linux tree
because the frontend (nor the backend) supported this interface.

Signed-off-by: default avatarKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
parent 4352b47a

include/xen/interface/io/blkif.h

+13 −0
Original line number Diff line number Diff line
@@ -44,6 +44,19 @@ typedef uint64_t blkif_sector_t; 
 */

#define BLKIF_OP_WRITE_BARRIER     2



/*

 * Recognised if "feature-flush-cache" is present in backend xenbus

 * info.  A flush will ask the underlying storage hardware to flush its

 * non-volatile caches as appropriate.  The "feature-flush-cache" node

 * contains a boolean indicating whether flush requests are likely to

 * succeed or fail. Either way, a flush request may fail at any time

 * with BLKIF_RSP_EOPNOTSUPP if it is unsupported by the underlying

 * block-device hardware. The boolean simply indicates whether or not it

 * is worthwhile for the frontend to attempt flushes.  If a backend does

 * not recognise BLKIF_OP_WRITE_FLUSH_CACHE, it should *not* create the

 * "feature-flush-cache" node!

 */

#define BLKIF_OP_FLUSH_DISKCACHE   3

/*

 * Maximum scatter/gather segments per request.

 * This is carefully chosen so that sizeof(struct blkif_ring) <= PAGE_SIZE.