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. Paolo
