Re: [Qemu-devel] [Qemu-block] [PATCH] gluster: allocate GlusterAIOCBs on the stack

[Stefan Hajnoczi]

On Thu, Oct 01, 2015 at 01:04:38PM +0200, Paolo Bonzini wrote:
> This is simpler now that the driver has been converted to coroutines.
> 
> Signed-off-by: Paolo Bonzini <address@hidden>
> ---
>  block/gluster.c | 86 
> ++++++++++++++++++++++-----------------------------------
>  1 file changed, 33 insertions(+), 53 deletions(-)

CCing Jeff on Gluster patches.

> diff --git a/block/gluster.c b/block/gluster.c
> index 1eb3a8c..0857c14 100644
> --- a/block/gluster.c
> +++ b/block/gluster.c
> @@ -429,28 +429,23 @@ static coroutine_fn int 
> qemu_gluster_co_write_zeroes(BlockDriverState *bs,
>          int64_t sector_num, int nb_sectors, BdrvRequestFlags flags)
>  {
>      int ret;
> -    GlusterAIOCB *acb = g_slice_new(GlusterAIOCB);
> +    GlusterAIOCB acb;
>      BDRVGlusterState *s = bs->opaque;
>      off_t size = nb_sectors * BDRV_SECTOR_SIZE;
>      off_t offset = sector_num * BDRV_SECTOR_SIZE;
>  
> -    acb->size = size;
> -    acb->ret = 0;
> -    acb->coroutine = qemu_coroutine_self();
> -    acb->aio_context = bdrv_get_aio_context(bs);
> +    acb.size = size;
> +    acb.ret = 0;
> +    acb.coroutine = qemu_coroutine_self();
> +    acb.aio_context = bdrv_get_aio_context(bs);
>  
> -    ret = glfs_zerofill_async(s->fd, offset, size, &gluster_finish_aiocb, 
> acb);
> +    ret = glfs_zerofill_async(s->fd, offset, size, gluster_finish_aiocb, 
> &acb);
>      if (ret < 0) {
> -        ret = -errno;
> -        goto out;
> +        return -errno;
>      }
>  
>      qemu_coroutine_yield();
> -    ret = acb->ret;
> -
> -out:
> -    g_slice_free(GlusterAIOCB, acb);
> -    return ret;
> +    return acb.ret;
>  }
>  
>  static inline bool gluster_supports_zerofill(void)
> @@ -541,35 +536,30 @@ static coroutine_fn int 
> qemu_gluster_co_rw(BlockDriverState *bs,
>          int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, int write)
>  {
>      int ret;
> -    GlusterAIOCB *acb = g_slice_new(GlusterAIOCB);
> +    GlusterAIOCB acb;
>      BDRVGlusterState *s = bs->opaque;
>      size_t size = nb_sectors * BDRV_SECTOR_SIZE;
>      off_t offset = sector_num * BDRV_SECTOR_SIZE;
>  
> -    acb->size = size;
> -    acb->ret = 0;
> -    acb->coroutine = qemu_coroutine_self();
> -    acb->aio_context = bdrv_get_aio_context(bs);
> +    acb.size = size;
> +    acb.ret = 0;
> +    acb.coroutine = qemu_coroutine_self();
> +    acb.aio_context = bdrv_get_aio_context(bs);
>  
>      if (write) {
>          ret = glfs_pwritev_async(s->fd, qiov->iov, qiov->niov, offset, 0,
> -            &gluster_finish_aiocb, acb);
> +            gluster_finish_aiocb, &acb);
>      } else {
>          ret = glfs_preadv_async(s->fd, qiov->iov, qiov->niov, offset, 0,
> -            &gluster_finish_aiocb, acb);
> +            gluster_finish_aiocb, &acb);
>      }
>  
>      if (ret < 0) {
> -        ret = -errno;
> -        goto out;
> +        return -errno;
>      }
>  
>      qemu_coroutine_yield();
> -    ret = acb->ret;
> -
> -out:
> -    g_slice_free(GlusterAIOCB, acb);
> -    return ret;
> +    return acb.ret;
>  }
>  
>  static int qemu_gluster_truncate(BlockDriverState *bs, int64_t offset)
> @@ -600,26 +590,21 @@ static coroutine_fn int 
> qemu_gluster_co_writev(BlockDriverState *bs,
>  static coroutine_fn int qemu_gluster_co_flush_to_disk(BlockDriverState *bs)
>  {
>      int ret;
> -    GlusterAIOCB *acb = g_slice_new(GlusterAIOCB);
> +    GlusterAIOCB acb;
>      BDRVGlusterState *s = bs->opaque;
>  
> -    acb->size = 0;
> -    acb->ret = 0;
> -    acb->coroutine = qemu_coroutine_self();
> -    acb->aio_context = bdrv_get_aio_context(bs);
> +    acb.size = 0;
> +    acb.ret = 0;
> +    acb.coroutine = qemu_coroutine_self();
> +    acb.aio_context = bdrv_get_aio_context(bs);
>  
> -    ret = glfs_fsync_async(s->fd, &gluster_finish_aiocb, acb);
> +    ret = glfs_fsync_async(s->fd, gluster_finish_aiocb, &acb);
>      if (ret < 0) {
> -        ret = -errno;
> -        goto out;
> +        return -errno;
>      }
>  
>      qemu_coroutine_yield();
> -    ret = acb->ret;
> -
> -out:
> -    g_slice_free(GlusterAIOCB, acb);
> -    return ret;
> +    return acb.ret;
>  }
>  
>  #ifdef CONFIG_GLUSTERFS_DISCARD
> @@ -627,28 +612,23 @@ static coroutine_fn int 
> qemu_gluster_co_discard(BlockDriverState *bs,
>          int64_t sector_num, int nb_sectors)
>  {
>      int ret;
> -    GlusterAIOCB *acb = g_slice_new(GlusterAIOCB);
> +    GlusterAIOCB acb;
>      BDRVGlusterState *s = bs->opaque;
>      size_t size = nb_sectors * BDRV_SECTOR_SIZE;
>      off_t offset = sector_num * BDRV_SECTOR_SIZE;
>  
> -    acb->size = 0;
> -    acb->ret = 0;
> -    acb->coroutine = qemu_coroutine_self();
> -    acb->aio_context = bdrv_get_aio_context(bs);
> +    acb.size = 0;
> +    acb.ret = 0;
> +    acb.coroutine = qemu_coroutine_self();
> +    acb.aio_context = bdrv_get_aio_context(bs);
>  
> -    ret = glfs_discard_async(s->fd, offset, size, &gluster_finish_aiocb, 
> acb);
> +    ret = glfs_discard_async(s->fd, offset, size, gluster_finish_aiocb, 
> &acb);
>      if (ret < 0) {
> -        ret = -errno;
> -        goto out;
> +        return -errno;
>      }
>  
>      qemu_coroutine_yield();
> -    ret = acb->ret;
> -
> -out:
> -    g_slice_free(GlusterAIOCB, acb);
> -    return ret;
> +    return acb.ret;
>  }
>  #endif
>  
> -- 
> 2.5.0
> 
>