search for: unfetch_descs

On 2020/6/10 ??7:05, Michael S. Tsirkin wrote: >>> +EXPORT_SYMBOL_GPL(vhost_get_vq_desc); >>> /* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */ >>> void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n) >>> { >>> + unfetch_descs(vq); >>> vq->last_avail_idx -= n; >> So unfetch_descs() has decreased last_avail_idx. >> Can we fix this by letting unfetch_descs() return the number and then we can >> do: >> >> int d = unfetch_descs(vq); >> vq->last_avail_idx -= (n > d) ?...

On 2020/6/10 ??7:05, Michael S. Tsirkin wrote: >>> +EXPORT_SYMBOL_GPL(vhost_get_vq_desc); >>> /* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */ >>> void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n) >>> { >>> + unfetch_descs(vq); >>> vq->last_avail_idx -= n; >> So unfetch_descs() has decreased last_avail_idx. >> Can we fix this by letting unfetch_descs() return the number and then we can >> do: >> >> int d = unfetch_descs(vq); >> vq->last_avail_idx -= (n > d) ?...

...rkin wrote: > > > > +EXPORT_SYMBOL_GPL(vhost_get_vq_desc); > > > > /* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */ > > > > void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n) > > > > { > > > > + unfetch_descs(vq); > > > > vq->last_avail_idx -= n; > > > So unfetch_descs() has decreased last_avail_idx. > > > Can we fix this by letting unfetch_descs() return the number and then we can > > > do: > > > > > > int d = unfetch_descs(vq); > >...

...p; vq->ndescs <= vhost_vq_num_batch_descs(vq); > + ret = fetch_buf(vq)) > + ; > + > + /* On success we expect some descs */ > + BUG_ON(ret > 0 && !vq->ndescs); > + return ret; > +} > + > +/* Reverse the effects of fetch_descs */ > +static void unfetch_descs(struct vhost_virtqueue *vq) > +{ > + int i; > + > + for (i = vq->first_desc; i < vq->ndescs; ++i) > + if (!(vq->descs[i].flags & VRING_DESC_F_NEXT)) > + vq->last_avail_idx -= 1; > + vq->ndescs = 0; > +} Is it better to set first_desc to zero here?...

...p; vq->ndescs <= vhost_vq_num_batch_descs(vq); > + ret = fetch_buf(vq)) > + ; > + > + /* On success we expect some descs */ > + BUG_ON(ret > 0 && !vq->ndescs); > + return ret; > +} > + > +/* Reverse the effects of fetch_descs */ > +static void unfetch_descs(struct vhost_virtqueue *vq) > +{ > + int i; > + > + for (i = vq->first_desc; i < vq->ndescs; ++i) > + if (!(vq->descs[i].flags & VRING_DESC_F_NEXT)) > + vq->last_avail_idx -= 1; > + vq->ndescs = 0; > +} Is it better to set first_desc to zero here?...

...); > > + ret = fetch_buf(vq)) > > + ; > > + > > + /* On success we expect some descs */ > > + BUG_ON(ret > 0 && !vq->ndescs); > > + return ret; > > +} > > + > > +/* Reverse the effects of fetch_descs */ > > +static void unfetch_descs(struct vhost_virtqueue *vq) > > +{ > > + int i; > > + > > + for (i = vq->first_desc; i < vq->ndescs; ++i) > > + if (!(vq->descs[i].flags & VRING_DESC_F_NEXT)) > > + vq->last_avail_idx -= 1; > > + vq->ndescs = 0; > > +} > &...

...rn 1; + + for (ret = 1; + ret > 0 && vq->ndescs <= vhost_vq_num_batch_descs(vq); + ret = fetch_buf(vq)) + ; + + /* On success we expect some descs */ + BUG_ON(ret > 0 && !vq->ndescs); + return ret; +} + +/* Reverse the effects of fetch_descs */ +static void unfetch_descs(struct vhost_virtqueue *vq) +{ + int i; + + for (i = vq->first_desc; i < vq->ndescs; ++i) + if (!(vq->descs[i].flags & VRING_DESC_F_NEXT)) + vq->last_avail_idx -= 1; + vq->ndescs = 0; +} + /* This looks in the virtqueue and for the first available buffer, and converts *...

...rn 1; + + for (ret = 1; + ret > 0 && vq->ndescs <= vhost_vq_num_batch_descs(vq); + ret = fetch_buf(vq)) + ; + + /* On success we expect some descs */ + BUG_ON(ret > 0 && !vq->ndescs); + return ret; +} + +/* Reverse the effects of fetch_descs */ +static void unfetch_descs(struct vhost_virtqueue *vq) +{ + int i; + + for (i = vq->first_desc; i < vq->ndescs; ++i) + if (!(vq->descs[i].flags & VRING_DESC_F_NEXT)) + vq->last_avail_idx -= 1; + vq->ndescs = 0; +} + /* This looks in the virtqueue and for the first available buffer, and converts *...

This adds infrastructure required for supporting multiple ring formats. The idea is as follows: we convert descriptors to an independent format first, and process that converting to iov later. Used ring is similar: we fetch into an independent struct first, convert that to IOV later. The point is that we have a tight loop that fetches descriptors, which is good for cache utilization. This will

This intentionally leaves "fixup" changes separate - hopefully that is enough to fix vhost-net crashes reported here, but it helps me keep track of what changed. I will naturally squash them later when we are done. This adds infrastructure required for supporting multiple ring formats. The idea is as follows: we convert descriptors to an independent format first, and process that

This intentionally leaves "fixup" changes separate - hopefully that is enough to fix vhost-net crashes reported here, but it helps me keep track of what changed. I will naturally squash them later when we are done. This adds infrastructure required for supporting multiple ring formats. The idea is as follows: we convert descriptors to an independent format first, and process that

This still causes corruption issues for people so don't try to use in production please. Posting to expedite debugging. This adds infrastructure required for supporting multiple ring formats. The idea is as follows: we convert descriptors to an independent format first, and process that converting to iov later. Used ring is similar: we fetch into an independent struct first, convert that to

This still causes corruption issues for people so don't try to use in production please. Posting to expedite debugging. This adds infrastructure required for supporting multiple ring formats. The idea is as follows: we convert descriptors to an independent format first, and process that converting to iov later. Used ring is similar: we fetch into an independent struct first, convert that to