From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:47080) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dddCX-0005dy-Ux for qemu-devel@nongnu.org; Fri, 04 Aug 2017 10:03:58 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dddCA-0007Fs-OB for qemu-devel@nongnu.org; Fri, 04 Aug 2017 10:03:41 -0400 Date: Fri, 4 Aug 2017 16:02:10 +0200 From: Kevin Wolf Message-ID: <20170804140210.GD4108@localhost.localdomain> References: <20170804105059.11941-1-berrange@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170804105059.11941-1-berrange@redhat.com> Subject: Re: [Qemu-devel] [PATCH] block: document semanatics of bdrv_co_preadv|pwritev List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Daniel P. Berrange" Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org, Stefan Hajnoczi , Fam Zheng , Max Reitz Am 04.08.2017 um 12:50 hat Daniel P. Berrange geschrieben: > Signed-off-by: Daniel P. Berrange > --- > include/block/block_int.h | 29 +++++++++++++++++++++++++++++ > 1 file changed, 29 insertions(+) > > diff --git a/include/block/block_int.h b/include/block/block_int.h > index d4f4ea7584..deb81a58bd 100644 > --- a/include/block/block_int.h > +++ b/include/block/block_int.h > @@ -147,12 +147,41 @@ struct BlockDriver { > > int coroutine_fn (*bdrv_co_readv)(BlockDriverState *bs, > int64_t sector_num, int nb_sectors, QEMUIOVector *qiov); > + > + /** > + * @offset: position in bytes to read at > + * @bytes: number of bytes to read > + * @qiov: the buffers to fill with read data > + * > + * @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 may be less than the total sizeof @iov, and will be > + * no larger than 'max_transfer'. Really? We are asserting that they match in bdrv_aligned_preadv(): assert(!qiov || bytes == qiov->size); Also, s/sizeof @iov/size of @qiov/ > + * > + * The buffer in @qiov may point directly to guest memory. > + */ > int coroutine_fn (*bdrv_co_preadv)(BlockDriverState *bs, > uint64_t offset, uint64_t bytes, QEMUIOVector *qiov, int flags); > int coroutine_fn (*bdrv_co_writev)(BlockDriverState *bs, > int64_t sector_num, int nb_sectors, QEMUIOVector *qiov); > int coroutine_fn (*bdrv_co_writev_flags)(BlockDriverState *bs, > int64_t sector_num, int nb_sectors, QEMUIOVector *qiov, int flags); > + /** > + * @offset: position in bytes to write at > + * @bytes: number of bytes to write > + * @qiov: the buffers containing data to write > + * > + * @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 may be less than the total sizeof @iov, and will be > + * no larger than 'max_transfer'. The same assertion exists in bdrv_aligned_pwritev() (and the same typo in your comment). > + * 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); Kevin