From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55831) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ddeKP-0006ig-M6 for qemu-devel@nongnu.org; Fri, 04 Aug 2017 11:15:54 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ddeKO-00005T-Mj for qemu-devel@nongnu.org; Fri, 04 Aug 2017 11:15:53 -0400 Date: Fri, 4 Aug 2017 16:15:44 +0100 From: "Daniel P. Berrange" Message-ID: <20170804151544.GF14504@redhat.com> Reply-To: "Daniel P. Berrange" References: <20170804140826.1351-1-berrange@redhat.com> <08b23cf1-5fc4-bb97-dad1-75103f3c5d8a@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <08b23cf1-5fc4-bb97-dad1-75103f3c5d8a@redhat.com> Subject: Re: [Qemu-devel] [PATCH v3] block: document semanatics of bdrv_co_preadv|pwritev List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Eric Blake Cc: qemu-devel@nongnu.org, Kevin Wolf , Max Reitz , qemu-block@nongnu.org On Fri, Aug 04, 2017 at 09:28:54AM -0500, Eric Blake wrote: > On 08/04/2017 09:08 AM, Daniel P. Berrange wrote: > > Signed-off-by: Daniel P. Berrange > > --- > > > > - Clarify that @bytes matches @qiov total size (Kevin) > > > > include/block/block_int.h | 31 +++++++++++++++++++++++++++++++ > > 1 file changed, 31 insertions(+) > > [looks like the nongnu.org infrastructure is having heavy load today, so > mails are getting through more slowly than usual - leads to lots of > crossed emails, where I'm seeing replies or direct sends sooner than > list copies] > > > + /** > > + * @offset: position in bytes to write at > > + * @bytes: number of bytes to write > > + * @qiov: the buffers containing data to write > > + * @flags: zero or more of bits allowed by 'supported_write_flags' > > maybe s/of // > > > + * > > + * @offset and @bytes will be a multiple of 'request_alignment', > > + * but the length of individual @qiov elements does not have to > > + * be a multiple. > > + * > > + * @bytes will always equal the total size of @qiov, and will be > > + * no larger than 'max_transfer'. > > + * > > + * The buffer in @qiov may point directly to guest memory. > > + */ > > int coroutine_fn (*bdrv_co_pwritev)(BlockDriverState *bs, > > uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags); > > Do we make guarantees that the driver callback is never reached if the > image is currently read-only? If so, is that a guarantee worth documenting? bdrv_co_pwritev() returns EPERM if bs->read_only, so it looks like you are right we have a guarantee we can document > Reviewed-by: Eric Blake Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|