On Thu, 06/23 16:37, Eric Blake wrote: > Improve the documentation of the write zeroes limits, to mention > additional constraints that drivers should observe. Worth squashing > into commit cf081fca, if that hadn't been pushed already :) > > Signed-off-by: Eric Blake <ebl...@redhat.com> > > --- > v3: new patch, split off from "block: Switch discard length bounds..." > --- > include/block/block_int.h | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/include/block/block_int.h b/include/block/block_int.h > index 7d2b152..7a4a00f 100644 > --- a/include/block/block_int.h > +++ b/include/block/block_int.h > @@ -331,11 +331,14 @@ typedef struct BlockLimits { > int64_t discard_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 */
"inherent 32-bit limit"? What is special about 32-bit other than this field is 32-bit? Anyway, Reviewed-by: Fam Zheng <f...@redhat.com> > int32_t max_pwrite_zeroes; > > /* optimal alignment for write zeroes requests in bytes, must be > - * power of 2, and less than max_pwrite_zeroes if that is set */ > + * power of 2, less than max_pwrite_zeroes if that is set, and > + * multiple of bs->request_alignment. May be 0 if > + * bs->request_alignment is good enough */ > uint32_t pwrite_zeroes_alignment; > > /* optimal transfer length in bytes (must be power of 2, and > -- > 2.5.5 >