virtio-blk: stop tracking old_bs

There is a 1:1 relation between VirtIOBlock and BlockDriverState instances, no need to track it because it won't change.

Signed-off-by Christoph Hellwig<[email protected]>

Index: qemu/hw/virtio-blk.c
===================================================================

hw/virtio-blk.c +10 -19

@@ -241,18 +241,17 @@ static void do_multiwrite(BlockDriverSta
  }
 
  static void virtio_blk_handle_flush(BlockRequest *blkreq, int *num_writes,
-    VirtIOBlockReq *req, BlockDriverState **old_bs)
+    VirtIOBlockReq *req)
  {
      BlockDriverAIOCB *acb;
 
      /*
       * Make sure all outstanding writes are posted to the backing device.
       */
-    if (*old_bs != NULL) {
-        do_multiwrite(*old_bs, blkreq, *num_writes);
+    if (*num_writes>  0) {
+        do_multiwrite(req->dev->bs, blkreq, *num_writes);
      }
      *num_writes = 0;
-    *old_bs = req->dev->bs;
 
      acb = bdrv_aio_flush(req->dev->bs, virtio_blk_flush_complete, req);
      if (!acb) {

@@ -261,19 +260,16 @@ static void virtio_blk_handle_flush(Bloc
  }
 
  static void virtio_blk_handle_write(BlockRequest *blkreq, int *num_writes,
-    VirtIOBlockReq *req, BlockDriverState **old_bs)
+    VirtIOBlockReq *req)
  {
      if (req->out->sector&  req->dev->sector_mask) {
          virtio_blk_rw_complete(req, -EIO);
          return;
      }
 
-    if (req->dev->bs != *old_bs || *num_writes == 32) {
-        if (*old_bs != NULL) {
-            do_multiwrite(*old_bs, blkreq, *num_writes);
-        }
+    if (*num_writes == 32) {
+        do_multiwrite(req->dev->bs, blkreq, *num_writes);
          *num_writes = 0;
-        *old_bs = req->dev->bs;
      }
 
      blkreq[*num_writes].sector = req->out->sector;

@@ -305,7 +301,6 @@ static void virtio_blk_handle_read(VirtI
  typedef struct MultiReqBuffer {
      BlockRequest        blkreq[32];
      int                 num_writes;
-    BlockDriverState    *old_bs;
  } MultiReqBuffer;
 
  static void virtio_blk_handle_request(VirtIOBlockReq *req,

@@ -326,15 +321,13 @@ static void virtio_blk_handle_request(Vi
      req->in = (void *)req->elem.in_sg[req->elem.in_num - 1].iov_base;
 
      if (req->out->type&  VIRTIO_BLK_T_FLUSH) {
-        virtio_blk_handle_flush(mrb->blkreq,&mrb->num_writes,
-            req,&mrb->old_bs);
+        virtio_blk_handle_flush(mrb->blkreq,&mrb->num_writes, req);
      } else if (req->out->type&  VIRTIO_BLK_T_SCSI_CMD) {
          virtio_blk_handle_scsi(req);
      } else if (req->out->type&  VIRTIO_BLK_T_OUT) {
          qemu_iovec_init_external(&req->qiov,&req->elem.out_sg[1],
                                   req->elem.out_num - 1);
-        virtio_blk_handle_write(mrb->blkreq,&mrb->num_writes,
-            req,&mrb->old_bs);
+        virtio_blk_handle_write(mrb->blkreq,&mrb->num_writes, req);
      } else {
          qemu_iovec_init_external(&req->qiov,&req->elem.in_sg[0],
                                   req->elem.in_num - 1);

@@ -348,7 +341,6 @@ static void virtio_blk_handle_output(Vir
      VirtIOBlockReq *req;
      MultiReqBuffer mrb = {
          .num_writes = 0,
-        .old_bs = NULL,
      };
 
      while ((req = virtio_blk_get_request(s))) {

@@ -356,7 +348,7 @@ static void virtio_blk_handle_output(Vir
      }
 
      if (mrb.num_writes>  0) {
-        do_multiwrite(mrb.old_bs, mrb.blkreq, mrb.num_writes);
+        do_multiwrite(s->bs, mrb.blkreq, mrb.num_writes);
      }
 
      /*

@@ -372,7 +364,6 @@ static void virtio_blk_dma_restart_bh(vo
      VirtIOBlockReq *req = s->rq;
      MultiReqBuffer mrb = {
          .num_writes = 0,
-        .old_bs = NULL,
      };
 
      qemu_bh_delete(s->bh);

@@ -386,7 +377,7 @@ static void virtio_blk_dma_restart_bh(vo
      }
 
      if (mrb.num_writes>  0) {
-        do_multiwrite(mrb.old_bs, mrb.blkreq, mrb.num_writes);
+        do_multiwrite(s->bs, mrb.blkreq, mrb.num_writes);
      }
  }