Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
---
- Clarify that @bytes matches @qiov total size (Kevin)
include/block/block_int.h | 31 +++++++++++++++++++++++++++++++
1 file changed, 31 insertions(+)
diff --git a/include/block/block_int.h b/include/block/block_int.h
index d4f4ea7584..4f7f20e56b 100644
--- a/include/block/block_int.h
+++ b/include/block/block_int.h
@@ -147,12 +147,43 @@ 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
+ * @flags: currently unused, always 0
+ *
+ * @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_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
+ * @flags: zero or more of bits allowed by 'supported_write_flags'
+ *
+ * @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);
--
2.13.3
On 08/04/2017 09:08 AM, Daniel P. Berrange wrote: > Signed-off-by: Daniel P. Berrange <berrange@redhat.com> > --- > > - 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? Reviewed-by: Eric Blake <eblake@redhat.com> -- Eric Blake, Principal Software Engineer Red Hat, Inc. +1-919-301-3266 Virtualization: qemu.org | libvirt.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 <berrange@redhat.com> > > --- > > > > - 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 <eblake@redhat.com> 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 :|
On Fri, Aug 04, 2017 at 03:08:26PM +0100, Daniel P. Berrange wrote: > Signed-off-by: Daniel P. Berrange <berrange@redhat.com> > --- > > - Clarify that @bytes matches @qiov total size (Kevin) > > include/block/block_int.h | 31 +++++++++++++++++++++++++++++++ > 1 file changed, 31 insertions(+) Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
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