[PATCH v2 01/18] hw/block/nvme: Move NvmeRequest has_sg field to a bit flag

[Dmitry Fomichev]

In addition to the existing has_sg flag, a few more Boolean
NvmeRequest flags are going to be introduced in subsequent patches.
Convert "has_sg" variable to "flags" and define NvmeRequestFlags
enum for individual flag values.

Signed-off-by: Dmitry Fomichev <dmitry.fomic...@wdc.com>
---
 hw/block/nvme.c | 8 +++-----
 hw/block/nvme.h | 6 +++++-
 2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/hw/block/nvme.c b/hw/block/nvme.c
index 1aee042d4c..3ed9f3d321 100644
--- a/hw/block/nvme.c
+++ b/hw/block/nvme.c
@@ -350,7 +350,7 @@ static void nvme_rw_cb(void *opaque, int ret)
         block_acct_failed(blk_get_stats(n->conf.blk), &req->acct);
         req->status = NVME_INTERNAL_DEV_ERROR;
     }
-    if (req->has_sg) {
+    if (req->flags & NVME_REQ_FLG_HAS_SG) {
         qemu_sglist_destroy(&req->qsg);
     }
     nvme_enqueue_req_completion(cq, req);
@@ -359,7 +359,6 @@ static void nvme_rw_cb(void *opaque, int ret)
 static uint16_t nvme_flush(NvmeCtrl *n, NvmeNamespace *ns, NvmeCmd *cmd,
     NvmeRequest *req)
 {
-    req->has_sg = false;
     block_acct_start(blk_get_stats(n->conf.blk), &req->acct, 0,
          BLOCK_ACCT_FLUSH);
     req->aiocb = blk_aio_flush(n->conf.blk, nvme_rw_cb, req);
@@ -383,7 +382,6 @@ static uint16_t nvme_write_zeros(NvmeCtrl *n, NvmeNamespace 
*ns, NvmeCmd *cmd,
         return NVME_LBA_RANGE | NVME_DNR;
     }
 
-    req->has_sg = false;
     block_acct_start(blk_get_stats(n->conf.blk), &req->acct, 0,
                      BLOCK_ACCT_WRITE);
     req->aiocb = blk_aio_pwrite_zeroes(n->conf.blk, offset, count,
@@ -422,14 +420,13 @@ static uint16_t nvme_rw(NvmeCtrl *n, NvmeNamespace *ns, 
NvmeCmd *cmd,
 
     dma_acct_start(n->conf.blk, &req->acct, &req->qsg, acct);
     if (req->qsg.nsg > 0) {
-        req->has_sg = true;
+        req->flags |= NVME_REQ_FLG_HAS_SG;
         req->aiocb = is_write ?
             dma_blk_write(n->conf.blk, &req->qsg, data_offset, 
BDRV_SECTOR_SIZE,
                           nvme_rw_cb, req) :
             dma_blk_read(n->conf.blk, &req->qsg, data_offset, BDRV_SECTOR_SIZE,
                          nvme_rw_cb, req);
     } else {
-        req->has_sg = false;
         req->aiocb = is_write ?
             blk_aio_pwritev(n->conf.blk, data_offset, &req->iov, 0, nvme_rw_cb,
                             req) :
@@ -917,6 +914,7 @@ static void nvme_process_sq(void *opaque)
         QTAILQ_REMOVE(&sq->req_list, req, entry);
         QTAILQ_INSERT_TAIL(&sq->out_req_list, req, entry);
         memset(&req->cqe, 0, sizeof(req->cqe));
+        req->flags = 0;
         req->cqe.cid = cmd.cid;
 
         status = sq->sqid ? nvme_io_cmd(n, &cmd, req) :
diff --git a/hw/block/nvme.h b/hw/block/nvme.h
index 1d30c0bca2..0460cc0e62 100644
--- a/hw/block/nvme.h
+++ b/hw/block/nvme.h
@@ -16,11 +16,15 @@ typedef struct NvmeAsyncEvent {
     NvmeAerResult result;
 } NvmeAsyncEvent;
 
+enum NvmeRequestFlags {
+    NVME_REQ_FLG_HAS_SG   = 1 << 0,
+};
+
 typedef struct NvmeRequest {
     struct NvmeSQueue       *sq;
     BlockAIOCB              *aiocb;
     uint16_t                status;
-    bool                    has_sg;
+    uint16_t                flags;
     NvmeCqe                 cqe;
     BlockAcctCookie         acct;
     QEMUSGList              qsg;
-- 
2.21.0