Re: [Qemu-devel] [PATCH] nbd: Initialize reply on failure

[Eric Blake <eblake@redhat.com>]

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On 7/19/19 10:53 AM, Philippe Mathieu-Daudé wrote:

>>      if (ret < 0) {
>> +        memset(reply, 0, sizeof *reply);
> 
> I never had problem with sizeof without parenthesis, but here I find it
> not easy to review.

Holdover from my work on GNU coding style projects: the rationale is
that you can tell 'sizeof(type)' apart from 'sizeof expr' if you always
omit the () in the latter case, which further makes it possible to tell
at a glance when you are using the expr form (preferred, because the
type of the expression can change and the sizeof is still correct) or a
type name (harder to audit, since changing a variable's type means you
also have to change any associated sizeof in later code using that
variable).  But I will readily admit qemu is not GNU style:

$ git grep 'sizeof ' | wc
    394    2500   29756
$ git grep 'sizeof(' | wc
   8899   46172  671537

so I've fixed it to use ().

> 
> Anyhow, this definitively looks like 4.1 material.
> 
> Preferently with sizeof(), but I don't mind, so:
> Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

Thanks.  Queued on my NBD tree for -rc2.

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org


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