Re: [Qemu-devel] [PATCH v6 03/12] migration: avoid concurrent invoke channel_close by different threads

[858585 jemmy]

This patch causes compile error when make check.

  LINK    tests/test-qdist
migration/qemu-file.o: In function `qemu_fclose':
/tmp/qemu-test/src/migration/qemu-file.c:331: undefined reference to
`migrate_get_current'
/tmp/qemu-test/src/migration/qemu-file.c:333: undefined reference to
`migrate_get_current'
collect2: error: ld returned 1 exit status
make: *** [tests/test-vmstate] Error 1

but I don't find an efficient way to fix it.
so I prefer to remove this patch from this series.
maybe it's not the best way to protect by
migrate_get_current()->qemu_file_close_lock.


On Fri, Aug 3, 2018 at 5:13 PM, Lidong Chen <address@hidden> wrote:
> From: Lidong Chen <address@hidden>
>
> The channel_close maybe invoked by different threads. For example, source
> qemu invokes qemu_fclose in main thread, migration thread and return path
> thread. Destination qemu invokes qemu_fclose in main thread, listen thread
> and COLO incoming thread.
>
> Signed-off-by: Lidong Chen <address@hidden>
> Reviewed-by: Daniel P. Berrangé <address@hidden>
> ---
>  migration/migration.c | 2 ++
>  migration/migration.h | 7 +++++++
>  migration/qemu-file.c | 6 ++++--
>  3 files changed, 13 insertions(+), 2 deletions(-)
>
> diff --git a/migration/migration.c b/migration/migration.c
> index b7d9854..a3a0756 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -3200,6 +3200,7 @@ static void migration_instance_finalize(Object *obj)
>      qemu_sem_destroy(&ms->postcopy_pause_sem);
>      qemu_sem_destroy(&ms->postcopy_pause_rp_sem);
>      qemu_sem_destroy(&ms->rp_state.rp_sem);
> +    qemu_mutex_destroy(&ms->qemu_file_close_lock);
>      error_free(ms->error);
>  }
>
> @@ -3236,6 +3237,7 @@ static void migration_instance_init(Object *obj)
>      qemu_sem_init(&ms->rp_state.rp_sem, 0);
>      qemu_sem_init(&ms->rate_limit_sem, 0);
>      qemu_mutex_init(&ms->qemu_file_lock);
> +    qemu_mutex_init(&ms->qemu_file_close_lock);
>  }
>
>  /*
> diff --git a/migration/migration.h b/migration/migration.h
> index 64a7b33..a50c2de 100644
> --- a/migration/migration.h
> +++ b/migration/migration.h
> @@ -122,6 +122,13 @@ struct MigrationState
>      QemuMutex qemu_file_lock;
>
>      /*
> +     * The to_src_file and from_dst_file point to one QIOChannelRDMA,
> +     * And qemu_fclose maybe invoked by different threads. use this lock
> +     * to avoid concurrent invoke channel_close by different threads.
> +     */
> +    QemuMutex qemu_file_close_lock;
> +
> +    /*
>       * Used to allow urgent requests to override rate limiting.
>       */
>      QemuSemaphore rate_limit_sem;
> diff --git a/migration/qemu-file.c b/migration/qemu-file.c
> index 977b9ae..74c48e0 100644
> --- a/migration/qemu-file.c
> +++ b/migration/qemu-file.c
> @@ -323,12 +323,14 @@ void qemu_update_position(QEMUFile *f, size_t size)
>   */
>  int qemu_fclose(QEMUFile *f)
>  {
> -    int ret;
> +    int ret, ret2;
>      qemu_fflush(f);
>      ret = qemu_file_get_error(f);
>
>      if (f->ops->close) {
> -        int ret2 = f->ops->close(f->opaque);
> +        qemu_mutex_lock(&migrate_get_current()->qemu_file_close_lock);
> +        ret2 = f->ops->close(f->opaque);
> +        qemu_mutex_unlock(&migrate_get_current()->qemu_file_close_lock);
>          if (ret >= 0) {
>              ret = ret2;
>          }
> --
> 1.8.3.1
>