On Tue, Aug 29, 2017 at 05:18:11PM +0200, Marc-André Lureau wrote: > Hi > > On Tue, Aug 29, 2017 at 5:09 PM, Michael S. Tsirkin <[email protected]> wrote: > > On Tue, Aug 29, 2017 at 05:04:34PM +0200, Marc-André Lureau wrote: > >> Hi > >> > >> On Tue, Aug 29, 2017 at 5:01 PM, Michael S. Tsirkin <[email protected]> > >> wrote: > >> > On Tue, Aug 29, 2017 at 04:48:04PM +0200, Marc-André Lureau wrote: > >> >> This is the same workaround as commit 523b018dde3b765, which was lost > >> >> with libvhost-user transition in commit e10e798c85c2331. > >> >> > >> >> Signed-off-by: Marc-André Lureau <[email protected]> > >> >> --- > >> >> contrib/libvhost-user/libvhost-user.h | 5 +++++ > >> >> contrib/libvhost-user/libvhost-user.c | 13 +++++++++++++ > >> >> 2 files changed, 18 insertions(+) > >> >> > >> >> diff --git a/contrib/libvhost-user/libvhost-user.h > >> >> b/contrib/libvhost-user/libvhost-user.h > >> >> index 53ef222c0b..aca71717c1 100644 > >> >> --- a/contrib/libvhost-user/libvhost-user.h > >> >> +++ b/contrib/libvhost-user/libvhost-user.h > >> >> @@ -132,6 +132,7 @@ typedef void (*vu_set_features_cb) (VuDev *dev, > >> >> uint64_t features); > >> >> typedef int (*vu_process_msg_cb) (VuDev *dev, VhostUserMsg *vmsg, > >> >> int *do_reply); > >> >> typedef void (*vu_queue_set_started_cb) (VuDev *dev, int qidx, bool > >> >> started); > >> >> +typedef bool (*vu_queue_resume_to_used_cb) (VuDev *dev, int qidx); > >> >> > >> >> typedef struct VuDevIface { > >> >> /* called by VHOST_USER_GET_FEATURES to get the features bitmask */ > >> >> @@ -148,6 +149,10 @@ typedef struct VuDevIface { > >> >> vu_process_msg_cb process_msg; > >> >> /* tells when queues can be processed */ > >> >> vu_queue_set_started_cb queue_set_started; > >> >> + /* If the queue must be resumed to vring.used->idx. */ > >> >> + /* This can help to support resuming on unmanaged exit/crash when > >> >> + * the slave/driver processes elements in order. */ > >> >> + vu_queue_resume_to_used_cb queue_resume_to_used; > >> >> } VuDevIface; > >> >> > >> >> typedef void (*vu_queue_handler_cb) (VuDev *dev, int qidx); > >> > > >> > Let's consider: this is only safe if queue is processed in order. > >> > So I think that would be a better name for the field. > >> > > >> That's what the comment say already :) > >> > >> Which name do you suggest? vu_queue_is_processed_in_order? > > > > Something like this. > > > >> Does that > >> imply it should always resume? > > > > Not sure I understand the question. > > If a "queue_is_processed_in_order", does that imply libvhost-user > should always resume it based on used_idx? I think it does, but the > correlation is less obvious than explicitly saying "resume_to_used".
Just add a comment then. You do not want low level details like used index in all backends. > > -- > Marc-André Lureau
