Re: [Qemu-devel] [PATCH 09/22] nbd: implement .bdrv_detach/attach_aio_context()

[Paolo Bonzini <pbonzini@redhat.com>]

Il 01/05/2014 16:54, Stefan Hajnoczi ha scritto:
> Drop the assumption that we're using the main AioContext.  Convert
> qemu_aio_set_fd_handler() calls to aio_set_fd_handler().
>
> The .bdrv_detach/attach_aio_context() interfaces also need to be
> implemented to move the socket fd handler from the old to the new
> AioContext.
>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---
>  block/nbd-client.c | 24 ++++++++++++---
>  block/nbd-client.h |  4 +++
>  block/nbd.c        | 87 +++++++++++++++++++++++++++++++++---------------------
>  3 files changed, 78 insertions(+), 37 deletions(-)
>
> diff --git a/block/nbd-client.c b/block/nbd-client.c
> index 7d698cb..6e1c97c 100644
> --- a/block/nbd-client.c
> +++ b/block/nbd-client.c
> @@ -49,7 +49,7 @@ static void nbd_teardown_connection(NbdClientSession *client)
>      shutdown(client->sock, 2);
>      nbd_recv_coroutines_enter_all(client);
>
> -    qemu_aio_set_fd_handler(client->sock, NULL, NULL, NULL);
> +    nbd_client_session_detach_aio_context(client);
>      closesocket(client->sock);
>      client->sock = -1;
>  }
> @@ -103,11 +103,14 @@ static int nbd_co_send_request(NbdClientSession *s,
>      struct nbd_request *request,
>      QEMUIOVector *qiov, int offset)
>  {
> +    AioContext *aio_context;
>      int rc, ret;
>
>      qemu_co_mutex_lock(&s->send_mutex);
>      s->send_coroutine = qemu_coroutine_self();
> -    qemu_aio_set_fd_handler(s->sock, nbd_reply_ready, nbd_restart_write, s);
> +    aio_context = bdrv_get_aio_context(s->bs);
> +    aio_set_fd_handler(aio_context, s->sock,
> +                       nbd_reply_ready, nbd_restart_write, s);
>      if (qiov) {
>          if (!s->is_unix) {
>              socket_set_cork(s->sock, 1);
> @@ -126,7 +129,7 @@ static int nbd_co_send_request(NbdClientSession *s,
>      } else {
>          rc = nbd_send_request(s->sock, request);
>      }
> -    qemu_aio_set_fd_handler(s->sock, nbd_reply_ready, NULL, s);
> +    aio_set_fd_handler(aio_context, s->sock, nbd_reply_ready, NULL, s);
>      s->send_coroutine = NULL;
>      qemu_co_mutex_unlock(&s->send_mutex);
>      return rc;
> @@ -335,6 +338,19 @@ int nbd_client_session_co_discard(NbdClientSession *client, int64_t sector_num,
>
>  }
>
> +void nbd_client_session_detach_aio_context(NbdClientSession *client)
> +{
> +    aio_set_fd_handler(bdrv_get_aio_context(client->bs), client->sock,
> +                       NULL, NULL, NULL);
> +}
> +
> +void nbd_client_session_attach_aio_context(NbdClientSession *client,
> +                                           AioContext *new_context)
> +{
> +    aio_set_fd_handler(new_context, client->sock,
> +                       nbd_reply_ready, NULL, client);
> +}
> +
>  void nbd_client_session_close(NbdClientSession *client)
>  {
>      struct nbd_request request = {
> @@ -381,7 +397,7 @@ int nbd_client_session_init(NbdClientSession *client, BlockDriverState *bs,
>      /* Now that we're connected, set the socket to be non-blocking and
>       * kick the reply mechanism.  */
>      qemu_set_nonblock(sock);
> -    qemu_aio_set_fd_handler(sock, nbd_reply_ready, NULL, client);
> +    nbd_client_session_attach_aio_context(client, bdrv_get_aio_context(bs));
>
>      logout("Established connection with NBD server\n");
>      return 0;
> diff --git a/block/nbd-client.h b/block/nbd-client.h
> index f2a6337..cd478f3 100644
> --- a/block/nbd-client.h
> +++ b/block/nbd-client.h
> @@ -47,4 +47,8 @@ int nbd_client_session_co_writev(NbdClientSession *client, int64_t sector_num,
>  int nbd_client_session_co_readv(NbdClientSession *client, int64_t sector_num,
>                                  int nb_sectors, QEMUIOVector *qiov);
>
> +void nbd_client_session_detach_aio_context(NbdClientSession *client);
> +void nbd_client_session_attach_aio_context(NbdClientSession *client,
> +                                           AioContext *new_context);
> +
>  #endif /* NBD_CLIENT_H */
> diff --git a/block/nbd.c b/block/nbd.c
> index 613f258..4eda095 100644
> --- a/block/nbd.c
> +++ b/block/nbd.c
> @@ -323,46 +323,67 @@ static int64_t nbd_getlength(BlockDriverState *bs)
>      return s->client.size;
>  }
>
> +static void nbd_detach_aio_context(BlockDriverState *bs)
> +{
> +    BDRVNBDState *s = bs->opaque;
> +
> +    nbd_client_session_detach_aio_context(&s->client);
> +}
> +
> +static void nbd_attach_aio_context(BlockDriverState *bs,
> +                                   AioContext *new_context)
> +{
> +    BDRVNBDState *s = bs->opaque;
> +
> +    nbd_client_session_attach_aio_context(&s->client, new_context);
> +}
> +
>  static BlockDriver bdrv_nbd = {
> -    .format_name         = "nbd",
> -    .protocol_name       = "nbd",
> -    .instance_size       = sizeof(BDRVNBDState),
> -    .bdrv_parse_filename = nbd_parse_filename,
> -    .bdrv_file_open      = nbd_open,
> -    .bdrv_co_readv       = nbd_co_readv,
> -    .bdrv_co_writev      = nbd_co_writev,
> -    .bdrv_close          = nbd_close,
> -    .bdrv_co_flush_to_os = nbd_co_flush,
> -    .bdrv_co_discard     = nbd_co_discard,
> -    .bdrv_getlength      = nbd_getlength,
> +    .format_name                = "nbd",
> +    .protocol_name              = "nbd",
> +    .instance_size              = sizeof(BDRVNBDState),
> +    .bdrv_parse_filename        = nbd_parse_filename,
> +    .bdrv_file_open             = nbd_open,
> +    .bdrv_co_readv              = nbd_co_readv,
> +    .bdrv_co_writev             = nbd_co_writev,
> +    .bdrv_close                 = nbd_close,
> +    .bdrv_co_flush_to_os        = nbd_co_flush,
> +    .bdrv_co_discard            = nbd_co_discard,
> +    .bdrv_getlength             = nbd_getlength,
> +    .bdrv_detach_aio_context    = nbd_detach_aio_context,
> +    .bdrv_attach_aio_context    = nbd_attach_aio_context,
>  };
>
>  static BlockDriver bdrv_nbd_tcp = {
> -    .format_name         = "nbd",
> -    .protocol_name       = "nbd+tcp",
> -    .instance_size       = sizeof(BDRVNBDState),
> -    .bdrv_parse_filename = nbd_parse_filename,
> -    .bdrv_file_open      = nbd_open,
> -    .bdrv_co_readv       = nbd_co_readv,
> -    .bdrv_co_writev      = nbd_co_writev,
> -    .bdrv_close          = nbd_close,
> -    .bdrv_co_flush_to_os = nbd_co_flush,
> -    .bdrv_co_discard     = nbd_co_discard,
> -    .bdrv_getlength      = nbd_getlength,
> +    .format_name                = "nbd",
> +    .protocol_name              = "nbd+tcp",
> +    .instance_size              = sizeof(BDRVNBDState),
> +    .bdrv_parse_filename        = nbd_parse_filename,
> +    .bdrv_file_open             = nbd_open,
> +    .bdrv_co_readv              = nbd_co_readv,
> +    .bdrv_co_writev             = nbd_co_writev,
> +    .bdrv_close                 = nbd_close,
> +    .bdrv_co_flush_to_os        = nbd_co_flush,
> +    .bdrv_co_discard            = nbd_co_discard,
> +    .bdrv_getlength             = nbd_getlength,
> +    .bdrv_detach_aio_context    = nbd_detach_aio_context,
> +    .bdrv_attach_aio_context    = nbd_attach_aio_context,
>  };
>
>  static BlockDriver bdrv_nbd_unix = {
> -    .format_name         = "nbd",
> -    .protocol_name       = "nbd+unix",
> -    .instance_size       = sizeof(BDRVNBDState),
> -    .bdrv_parse_filename = nbd_parse_filename,
> -    .bdrv_file_open      = nbd_open,
> -    .bdrv_co_readv       = nbd_co_readv,
> -    .bdrv_co_writev      = nbd_co_writev,
> -    .bdrv_close          = nbd_close,
> -    .bdrv_co_flush_to_os = nbd_co_flush,
> -    .bdrv_co_discard     = nbd_co_discard,
> -    .bdrv_getlength      = nbd_getlength,
> +    .format_name                = "nbd",
> +    .protocol_name              = "nbd+unix",
> +    .instance_size              = sizeof(BDRVNBDState),
> +    .bdrv_parse_filename        = nbd_parse_filename,
> +    .bdrv_file_open             = nbd_open,
> +    .bdrv_co_readv              = nbd_co_readv,
> +    .bdrv_co_writev             = nbd_co_writev,
> +    .bdrv_close                 = nbd_close,
> +    .bdrv_co_flush_to_os        = nbd_co_flush,
> +    .bdrv_co_discard            = nbd_co_discard,
> +    .bdrv_getlength             = nbd_getlength,
> +    .bdrv_detach_aio_context    = nbd_detach_aio_context,
> +    .bdrv_attach_aio_context    = nbd_attach_aio_context,
>  };
>
>  static void bdrv_nbd_init(void)
>

Acked-by: Paolo Bonzini <pbonzini@redhat.com>