[Qemu-devel] Re: [PATCH] Fix VM state change handlers running out of order

[Gleb Natapov <gleb@redhat.com>]

On Tue, Jul 28, 2009 at 02:33:41PM -0400, Markus Armbruster wrote:
> Fix this by moving the actual write from each VM state change handler
> into a new bottom half (suggested by Gleb Natapov).
> 
This is exactly what I meant. Thanks.

> Signed-off-by: Markus Armbruster <armbru@redhat.com>
Acked-by: Gleb Natapov <gleb@redhat.com>

> ---
>  hw/ide.c        |   22 +++++++++++++++++++---
>  hw/scsi-disk.c  |   21 ++++++++++++++++++---
>  hw/virtio-blk.c |   20 +++++++++++++++++---
>  3 files changed, 54 insertions(+), 9 deletions(-)
> 
> diff --git a/hw/ide.c b/hw/ide.c
> index 1e56786..2eea438 100644
> --- a/hw/ide.c
> +++ b/hw/ide.c
> @@ -501,6 +501,7 @@ typedef struct BMDMAState {
>      QEMUIOVector qiov;
>      int64_t sector_num;
>      uint32_t nsector;
> +    QEMUBH *bh;
>  } BMDMAState;
>  
>  typedef struct PCIIDEState {
> @@ -1109,11 +1110,13 @@ static void ide_sector_write(IDEState *s)
>      }
>  }
>  
> -static void ide_dma_restart_cb(void *opaque, int running, int reason)
> +static void ide_dma_restart_bh(void *opaque)
>  {
>      BMDMAState *bm = opaque;
> -    if (!running)
> -        return;
> +
> +    qemu_bh_delete(bm->bh);
> +    bm->bh = NULL;
> +
>      if (bm->status & BM_STATUS_DMA_RETRY) {
>          bm->status &= ~BM_STATUS_DMA_RETRY;
>          ide_dma_restart(bm->ide_if);
> @@ -1123,6 +1126,19 @@ static void ide_dma_restart_cb(void *opaque, int running, int reason)
>      }
>  }
>  
> +static void ide_dma_restart_cb(void *opaque, int running, int reason)
> +{
> +    BMDMAState *bm = opaque;
> +
> +    if (!running)
> +        return;
> +
> +    if (!bm->bh) {
> +        bm->bh = qemu_bh_new(ide_dma_restart_bh, bm);
> +        qemu_bh_schedule(bm->bh);
> +    }
> +}
> +
>  static void ide_write_dma_cb(void *opaque, int ret)
>  {
>      BMDMAState *bm = opaque;
> diff --git a/hw/scsi-disk.c b/hw/scsi-disk.c
> index 8b6426f..5b825c9 100644
> --- a/hw/scsi-disk.c
> +++ b/hw/scsi-disk.c
> @@ -74,6 +74,7 @@ struct SCSIDeviceState
>      scsi_completionfn completion;
>      void *opaque;
>      char drive_serial_str[21];
> +    QEMUBH *bh;
>  };
>  
>  /* Global pool of SCSIRequest structures.  */
> @@ -308,12 +309,13 @@ static int scsi_write_data(SCSIDevice *d, uint32_t tag)
>      return 0;
>  }
>  
> -static void scsi_dma_restart_cb(void *opaque, int running, int reason)
> +static void scsi_dma_restart_bh(void *opaque)
>  {
>      SCSIDeviceState *s = opaque;
>      SCSIRequest *r = s->requests;
> -    if (!running)
> -        return;
> +
> +    qemu_bh_delete(s->bh);
> +    s->bh = NULL;
>  
>      while (r) {
>          if (r->status & SCSI_REQ_STATUS_RETRY) {
> @@ -324,6 +326,19 @@ static void scsi_dma_restart_cb(void *opaque, int running, int reason)
>      }
>  }
>  
> +static void scsi_dma_restart_cb(void *opaque, int running, int reason)
> +{
> +    SCSIDeviceState *s = opaque;
> +
> +    if (!running)
> +        return;
> +
> +    if (!s->bh) {
> +        s->bh = qemu_bh_new(scsi_dma_restart_bh, s);
> +        qemu_bh_schedule(s->bh);
> +    }
> +}
> +
>  /* Return a pointer to the data buffer.  */
>  static uint8_t *scsi_get_buf(SCSIDevice *d, uint32_t tag)
>  {
> diff --git a/hw/virtio-blk.c b/hw/virtio-blk.c
> index 2beff52..5036b5b 100644
> --- a/hw/virtio-blk.c
> +++ b/hw/virtio-blk.c
> @@ -26,6 +26,7 @@ typedef struct VirtIOBlock
>      VirtQueue *vq;
>      void *rq;
>      char serial_str[BLOCK_SERIAL_STRLEN + 1];
> +    QEMUBH *bh;
>  } VirtIOBlock;
>  
>  static VirtIOBlock *to_virtio_blk(VirtIODevice *vdev)
> @@ -302,13 +303,13 @@ static void virtio_blk_handle_output(VirtIODevice *vdev, VirtQueue *vq)
>       */
>  }
>  
> -static void virtio_blk_dma_restart_cb(void *opaque, int running, int reason)
> +static void virtio_blk_dma_restart_bh(void *opaque)
>  {
>      VirtIOBlock *s = opaque;
>      VirtIOBlockReq *req = s->rq;
>  
> -    if (!running)
> -        return;
> +    qemu_bh_delete(s->bh);
> +    s->bh = NULL;
>  
>      s->rq = NULL;
>  
> @@ -318,6 +319,19 @@ static void virtio_blk_dma_restart_cb(void *opaque, int running, int reason)
>      }
>  }
>  
> +static void virtio_blk_dma_restart_cb(void *opaque, int running, int reason)
> +{
> +    VirtIOBlock *s = opaque;
> +
> +    if (!running)
> +        return;
> +
> +    if (!s->bh) {
> +        s->bh = qemu_bh_new(virtio_blk_dma_restart_bh, s);
> +        qemu_bh_schedule(s->bh);
> +    }
> +}
> +
>  static void virtio_blk_reset(VirtIODevice *vdev)
>  {
>      /*
> -- 
> 1.6.2.5

--
			Gleb.