On Thu, 06/16 08:21, Eric Blake wrote:
> On 06/15/2016 11:46 PM, Fam Zheng wrote:
> > On Tue, 06/14 15:30, Eric Blake wrote:
> >> Sector-based limits are awkward to think about; in our on-going
> >> quest to move to byte-based interfaces, convert max_discard and
> >> discard_alignment. Rename them, using 'pdiscard' as an aid to
> >> track which remaining discard interfaces need conversion, and so
> >> that the compiler will help us catch the change in semantics
> >> across any rebased code. In iscsi.c, sector_limits_lun2qemu()
> >> is no longer needed; and the BlockLimits type is now completely
> >> byte-based.
> >>
> >> Signed-off-by: Eric Blake <ebl...@redhat.com>
> >>
>
> >>
> >> typedef struct BlockLimits {
> >> - /* maximum number of sectors that can be discarded at once */
> >> - int max_discard;
> >> + /* maximum number of bytes that can be discarded at once (since it
> >> + * is signed, it must be < 2G, if set), should be multiple of
> >> + * pdiscard_alignment, but need not be power of 2. May be 0 if no
> >> + * inherent 32-bit limit */
> >> + int32_t max_pdiscard;
> >
> > Why not use uint32_t?
> >
> >>
> >> - /* optimal alignment for discard requests in sectors */
> >> - int64_t discard_alignment;
> >> + /* optimal alignment for discard requests in bytes, must be power
> >> + * of 2, less than max_discard if that is set, and multiple of
> >> + * bs->request_alignment. May be 0 if bs->request_alignment is
> >> + * good enough */
> >> + uint32_t pdiscard_alignment;
> >>
> >> /* maximum number of bytes that can zeroized at once (since it is
> >> - * signed, it must be < 2G, if set) */
> >> + * signed, it must be < 2G, if set), should be multiple of
> >> + * pwrite_zeroes_alignment. May be 0 if no inherent 32-bit limit */
> >> int32_t max_pwrite_zeroes;
>
> Because max_pwrite_zeroes didn't.
>
> And because we're still limited by INT_MAX (or it's alternative spelling
> BDRV_REQUEST_MAX_SECTORS).
>
> Maybe we should switch both to uint32_t, but that can be a followup.
>
OK, thanks!
Reviewed-by: Fam Zheng <f...@redhat.com>
