From d901f3c457ade0b4934427c0e8608dea31610720 Mon Sep 17 00:00:00 2001
From: Peter Lieven <pl@kamp.de>
Date: Mon, 2 Feb 2015 14:52:19 +0100
Subject: [PATCH] hw/virtio-blk: add a constant for max number of merged
 requests

As it was not obvious (at least for me) where the 32 comes from;
add a constant for it.

Signed-off-by: Peter Lieven <pl@kamp.de>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
---
 hw/block/virtio-blk.c          | 2 +-
 include/hw/virtio/virtio-blk.h | 4 +++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c
index 4032fcae27..e04adb8f16 100644
--- a/hw/block/virtio-blk.c
+++ b/hw/block/virtio-blk.c
@@ -360,7 +360,7 @@ static void virtio_blk_handle_write(VirtIOBlockReq *req, MultiReqBuffer *mrb)
     block_acct_start(blk_get_stats(req->dev->blk), &req->acct, req->qiov.size,
                      BLOCK_ACCT_WRITE);
 
-    if (mrb->num_writes == 32) {
+    if (mrb->num_writes == VIRTIO_BLK_MAX_MERGE_REQS) {
         virtio_submit_multiwrite(req->dev->blk, mrb);
     }
 
diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h
index 4652b70b5d..6ef3fa57cf 100644
--- a/include/hw/virtio/virtio-blk.h
+++ b/include/hw/virtio/virtio-blk.h
@@ -134,8 +134,10 @@ typedef struct VirtIOBlock {
     struct VirtIOBlockDataPlane *dataplane;
 } VirtIOBlock;
 
+#define VIRTIO_BLK_MAX_MERGE_REQS 32
+
 typedef struct MultiReqBuffer {
-    BlockRequest        blkreq[32];
+    BlockRequest        blkreq[VIRTIO_BLK_MAX_MERGE_REQS];
     unsigned int        num_writes;
 } MultiReqBuffer;