Re: [PATCH] xen: fix qdisk BLKIF_OP_DISCARD for 32/64 word size mix

[Juergen Gross <jgross@suse.com>]

On 16/06/16 12:54, Jan Beulich wrote:
>>>> On 16.06.16 at 12:02, <JGross@suse.com> wrote:
>> In case the word size of the domU and qemu running the qdisk backend
>> differ BLKIF_OP_DISCARD will not work reliably, as the request
>> structure in the ring have different layouts for different word size.
>>
>> Correct this by copying the request structure in case of different
>> word size element by element in the BLKIF_OP_DISCARD case, too.
>>
>> Signed-off-by: Juergen Gross <jgross@suse.com>
> 
> With the indentation (tabs vs blanks) fixed

Hmm, qemu coding style is to use blanks. I could:
a) leave the patch as is (changed lines indented with blanks)
b) use tabs to indent (style of the modified file up to now)
c) change the style of the file in this patch
d) change the style of the file in a separate patch

Any preferences?

> Reviewed-by: Jan Beulich <jbeulich@suse.com>
> 
> And maybe ...
> 
>> @@ -82,7 +98,7 @@ static inline void blkif_get_x86_32_req(blkif_request_t *dst, blkif_x86_32_reque
>>  	/* Prevent the compiler from using src->... instead. */
>>  	barrier();
>>  	if (dst->operation == BLKIF_OP_DISCARD) {
>> -		struct blkif_request_discard *s = (void *)src;
>> +                struct blkif_x86_32_request_discard *s = (void *)src;
> 
> ... it would also be worth adding const here and ...
> 
>> @@ -105,7 +121,7 @@ static inline void blkif_get_x86_64_req(blkif_request_t *dst, blkif_x86_64_reque
>>  	/* Prevent the compiler from using src->... instead. */
>>  	barrier();
>>  	if (dst->operation == BLKIF_OP_DISCARD) {
>> -		struct blkif_request_discard *s = (void *)src;
>> +                struct blkif_x86_64_request_discard *s = (void *)src;
> 
> ... here.

Okay.


Juergen

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