On 05.07.2016 17:24, Colin Lord wrote:
> This puts the bochs probe function into its own separate file as part of
> the process of modularizing block drivers. Having the probe functions
> separate from the rest of the driver allows us to probe without having
> to potentially unnecessarily load the driver.
> 
> Signed-off-by: Colin Lord <clord@redhat.com>
> ---
>  block/Makefile.objs          |  1 +
>  block/bochs.c                | 55 ++------------------------------------------
>  block/probe/bochs.c          | 21 +++++++++++++++++
>  include/block/driver/bochs.h | 40 ++++++++++++++++++++++++++++++++
>  include/block/probe.h        |  6 +++++
>  5 files changed, 70 insertions(+), 53 deletions(-)
>  create mode 100644 block/probe/bochs.c
>  create mode 100644 include/block/driver/bochs.h
>  create mode 100644 include/block/probe.h
> 

[...]

> diff --git a/block/probe/bochs.c b/block/probe/bochs.c
> new file mode 100644
> index 0000000..8adc09f
> --- /dev/null
> +++ b/block/probe/bochs.c
> @@ -0,0 +1,21 @@
> +#include "qemu/osdep.h"
> +#include "block/block_int.h"
> +#include "block/probe.h"
> +#include "block/driver/bochs.h"
> +
> +int bochs_probe(const uint8_t *buf, int buf_size, const char *filename)
> +{
> +    const struct bochs_header *bochs = (const void *)buf;
> +
> +    if (buf_size < HEADER_SIZE)
> +	return 0;
> +
> +    if (!strcmp(bochs->magic, HEADER_MAGIC) &&
> +	!strcmp(bochs->type, REDOLOG_TYPE) &&
> +	!strcmp(bochs->subtype, GROWING_TYPE) &&
> +	((le32_to_cpu(bochs->version) == HEADER_VERSION) ||
> +	(le32_to_cpu(bochs->version) == HEADER_V1)))
> +	return 100;
> +
> +    return 0;
> +}

Not sure what to do about the coding style here. Some people prefer code
movement to be pure, but I feel bad about doing code movement and then
leaving the code wrongly formatted. That is, in my opinion, every patch
should pass checkpatch.pl (but I won't object to a patch that doesn't
pass checkpatch.pl simply because of pre-existing code).

> diff --git a/include/block/driver/bochs.h b/include/block/driver/bochs.h
> new file mode 100644
> index 0000000..cd87256
> --- /dev/null
> +++ b/include/block/driver/bochs.h

Kevin's point that we maybe should just put this into block/ itself
(just like block/qcow2.h) is not a bad one, but I'm fine either way.

> @@ -0,0 +1,40 @@
> +#ifndef BOCHS_H
> +#define BOCHS_H

Maybe BLOCK_BOCHS_H would be better, considering that Bochs is primarily
a system emulator and its image format doesn't really have an own name.

(Compare block/qcow2.h, which uses BLOCK_QCOW2_H.)

Independently of what you decide to do in any of these three places:

Reviewed-by: Max Reitz <mreitz@redhat.com>