Il 13/09/2013 12:44, Peter Lieven ha scritto:
On 13.09.2013 12:34, Paolo Bonzini wrote:
Il 13/09/2013 12:25, Peter Lieven ha scritto:
+ /* maximum number of sectors that can be discarded at once */
+ int max_discard;
+ /* maximum number of sectors that can zeroized at once */
+ int max_write_zeroes;
These should not be needed outside the driver.
If you want to make them private between block.c and block/iscsi.c, you
can add them to BlockDriverState.
The question is, if the discard_zeroes or discard_write_zeroes is needed
outside the driver as well?
I can put the max_* information in the block driver state. I also thought
to add alignment and granularity information even if they are currently
not yet used.
Yeah, in fact bdrv_write_zeroes and bdrv_discard can be taught to split
requests according to these parameters instead of introducing a new
function bdrv_zeroize. You don't need bdrv_zeroize I think; you can
simply use bdrv_write_zeroes. This is why I don't like this information
in BlockDriverInfo.
On the contrary, discard_write_zeroes is useful to "generic" clients,
and your qemu-img patch shows why.
Discard_zeroes is somewhere in the middle. You only use it in
bdrv_get_block_status, but it is not something that should be hidden to
users of the high-level block.c API. So it is fine to leave it in
BlockDriverInfo.