Re: [Xen-devel] [PATCH v3 10/12] livepatch: Handle arbitrary size names with the list operation

[Jan Beulich <jbeulich@xxxxxxxx>]

On 17.09.2019 10:40,  Wieczorkiewicz, Pawel  wrote:
> 
> 
> On 17. Sep 2019, at 10:27, Jan Beulich 
> <jbeulich@xxxxxxxx<mailto:jbeulich@xxxxxxxx>> wrote:
> 
> On 16.09.2019 12:59, Pawel Wieczorkiewicz wrote:
> @@ -951,11 +952,13 @@ struct xen_sysctl_livepatch_list {
>                                                amount of payloads and version.
>                                                OUT: How many payloads left. */
>     uint32_t pad;                           /* IN: Must be zero. */
> +    uint64_t name_total_size;               /* OUT: Total size of all 
> transfer names */
> 
> Why uint64_t and not uint32_t? You don't expect this to grow
> beyond 4GiB, do you?
> 
> I don’t, but uint32_t is not really compatible with size_t.
> And I was thought to always use size_t compatible types for sizes.

That's a fair point, but I think we use 32-bit sizes elsewhere
as well, when crossing the 4GiB boundary would seem entirely
unexpected.

But what's worse here - you shouldn't use plain uint64_t in
sysctl.h (and domctl.h) anyway. If anything, you ought to use
uint64_aligned_t. (Going through the file I notice a few other
bad instances have crept in.)

> Anyway, I do not mind changing this to whatever type you prefer.

Well, preference - if anyone's - would be the livepatch maintainers'
one here.

Also - can you please see about adjusting your reply style? In plain
text mode it's impossible to tell context from your responses.

Jan

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