Re: [RFC PATCH v2 02/25] include/sysemu/block-backend: split header into I/O and global state (GS) API

[Stefan Hajnoczi <stefanha@redhat.com>]

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On Tue, Oct 05, 2021 at 10:31:52AM -0400, Emanuele Giuseppe Esposito wrote:
> +/*
> + * Global state (GS) API. These functions run under the BQL lock.
> + *
> + * If a function modifies the graph, it also uses drain and/or
> + * aio_context_acquire/release to be sure it has unique access.
> + * aio_context locking is needed together with BQL because of
> + * the thread-safe I/O API that concurrently runs and accesses
> + * the graph without the BQL.
> + *
> + * It is important to note that not all of these functions are
> + * necessarily limited to running under the BQL, but they would
> + * require additional auditing and may small thread-safety changes

s/may/many/

> diff --git a/include/sysemu/block-backend-io.h b/include/sysemu/block-backend-io.h
> new file mode 100644
> index 0000000000..a77b2080ce
> --- /dev/null
> +++ b/include/sysemu/block-backend-io.h
> @@ -0,0 +1,130 @@
> +/*
> + * QEMU Block backends
> + *
> + * Copyright (C) 2014-2016 Red Hat, Inc.
> + *
> + * Authors:
> + *  Markus Armbruster <armbru@redhat.com>,
> + *
> + * This work is licensed under the terms of the GNU LGPL, version 2.1
> + * or later.  See the COPYING.LIB file in the top-level directory.
> + */
> +
> +#ifndef BLOCK_BACKEND_IO_H
> +#define BLOCK_BACKEND_IO_H
> +
> +#include "block-backend-common.h"
> +
> +/*
> + * I/O API functions. These functions are thread-safe, and therefore
> + * can run in any thread as long as they have called
> + * aio_context_acquire/release().

The meaning of "they" is not 100% clear. It could be the thread or the
I/O API functions. I suggest making it explicit:

  s/they have/the thread has/

Otherwise:
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

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