Re: [PATCH v6 06/11] block: make BlockLimits::max_pwrite_zeroes 64bit

[Eric Blake <eblake@redhat.com>]

On Fri, Sep 03, 2021 at 01:28:02PM +0300, Vladimir Sementsov-Ogievskiy wrote:
> We are going to support 64 bit write-zeroes requests. Now update the
> limit variable. It's absolutely safe. The variable is set in some
> drivers, and used in bdrv_co_do_pwrite_zeroes().
> 
> Update also max_write_zeroes variable in bdrv_co_do_pwrite_zeroes(), so
> that bdrv_co_do_pwrite_zeroes() is now prepared to 64bit requests. The
> remaining logic including num, offset and bytes variables is already
> supporting 64bit requests.
> 
> So the only thing that prevents 64 bit requests is limiting
> max_write_zeroes variable to INT_MAX in bdrv_co_do_pwrite_zeroes().
> We'll drop this limitation after updating all block drivers.
> 
> Ah, we also have bdrv_check_request32() in bdrv_co_pwritev_part(). It
> will be modified to do bdrv_check_request() for write-zeroes path.
> 
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> ---
>  include/block/block_int.h | 9 +++++----
>  block/io.c                | 2 +-
>  2 files changed, 6 insertions(+), 5 deletions(-)

Reviewed-by: Eric Blake <eblake@redhat.com>

-- 
Eric Blake, Principal Software Engineer
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