| Message ID | 20230603204939.1598818-4-AVKrasnov@sberdevices.ru (mailing list archive) |
|---|---|
| State | RFC |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | vsock: MSG_ZEROCOPY flag support | expand |
On Sat, Jun 03, 2023 at 11:49:25PM +0300, Arseniy Krasnov wrote: > For non-linear skb use its pages from fragment array as buffers in > virtio tx queue. These pages are already pinned by 'get_user_pages()' > during such skb creation. > > Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru> > --- > net/vmw_vsock/virtio_transport.c | 37 ++++++++++++++++++++++++++------ > 1 file changed, 31 insertions(+), 6 deletions(-) > > diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c > index e95df847176b..6053d8341091 100644 > --- a/net/vmw_vsock/virtio_transport.c > +++ b/net/vmw_vsock/virtio_transport.c > @@ -100,7 +100,9 @@ virtio_transport_send_pkt_work(struct work_struct *work) > vq = vsock->vqs[VSOCK_VQ_TX]; > > for (;;) { > - struct scatterlist hdr, buf, *sgs[2]; > + /* +1 is for packet header. */ > + struct scatterlist *sgs[MAX_SKB_FRAGS + 1]; > + struct scatterlist bufs[MAX_SKB_FRAGS + 1]; > int ret, in_sg = 0, out_sg = 0; > struct sk_buff *skb; > bool reply; > @@ -111,12 +113,35 @@ virtio_transport_send_pkt_work(struct work_struct *work) > > virtio_transport_deliver_tap_pkt(skb); > reply = virtio_vsock_skb_reply(skb); > + sg_init_one(&bufs[0], virtio_vsock_hdr(skb), sizeof(*virtio_vsock_hdr(skb))); > + sgs[out_sg++] = &bufs[0]; > + > + if (skb_is_nonlinear(skb)) { > + struct skb_shared_info *si; > + int i; > + > + si = skb_shinfo(skb); > + > + for (i = 0; i < si->nr_frags; i++) { > + skb_frag_t *skb_frag = &si->frags[i]; > + void *va = page_to_virt(skb_frag->bv_page); > + > + /* We will use 'page_to_virt()' for userspace page here, > + * because virtio layer will call 'virt_to_phys()' later > + * to fill buffer descriptor. We don't touch memory at > + * "virtual" address of this page. > + */ > + sg_init_one(&bufs[i + 1], > + va + skb_frag->bv_offset, > + skb_frag->bv_len); > + sgs[out_sg++] = &bufs[i + 1]; > + } > + } else { > + if (skb->len > 0) { > + sg_init_one(&bufs[1], skb->data, skb->len); > + sgs[out_sg++] = &bufs[1]; > + } > > - sg_init_one(&hdr, virtio_vsock_hdr(skb), sizeof(*virtio_vsock_hdr(skb))); > - sgs[out_sg++] = &hdr; > - if (skb->len > 0) { > - sg_init_one(&buf, skb->data, skb->len); > - sgs[out_sg++] = &buf; > } > > ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, skb, GFP_KERNEL); > -- > 2.25.1 > LGTM. Reviewed-by: Bobby Eshleman <bobby.eshleman@bytedance.com>
On Sat, Jun 03, 2023 at 11:49:25PM +0300, Arseniy Krasnov wrote: >For non-linear skb use its pages from fragment array as buffers in >virtio tx queue. These pages are already pinned by 'get_user_pages()' >during such skb creation. > >Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru> >--- > net/vmw_vsock/virtio_transport.c | 37 ++++++++++++++++++++++++++------ > 1 file changed, 31 insertions(+), 6 deletions(-) > >diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c >index e95df847176b..6053d8341091 100644 >--- a/net/vmw_vsock/virtio_transport.c >+++ b/net/vmw_vsock/virtio_transport.c >@@ -100,7 +100,9 @@ virtio_transport_send_pkt_work(struct work_struct *work) > vq = vsock->vqs[VSOCK_VQ_TX]; > > for (;;) { >- struct scatterlist hdr, buf, *sgs[2]; >+ /* +1 is for packet header. */ >+ struct scatterlist *sgs[MAX_SKB_FRAGS + 1]; >+ struct scatterlist bufs[MAX_SKB_FRAGS + 1]; > int ret, in_sg = 0, out_sg = 0; > struct sk_buff *skb; > bool reply; >@@ -111,12 +113,35 @@ virtio_transport_send_pkt_work(struct work_struct *work) > > virtio_transport_deliver_tap_pkt(skb); > reply = virtio_vsock_skb_reply(skb); >+ sg_init_one(&bufs[0], virtio_vsock_hdr(skb), sizeof(*virtio_vsock_hdr(skb))); >+ sgs[out_sg++] = &bufs[0]; Can we use out_sg also to index bufs (here and in the rest of the code)? E.g. sg_init_one(&bufs[out_sg], ...) sgs[out_sg] = &bufs[out_sg]; ++out_sg; ... if (skb->len > 0) { sg_init_one(&bufs[out_sg], skb->data, skb->len); sgs[out_sg] = &bufs[out_sg]; ++out_sg; } etc... >+ For readability, I would move the smaller branch above: if (!skb_is_nonlinear(skb)) { // small block ... } else { // big block ... } >+ if (skb_is_nonlinear(skb)) { >+ struct skb_shared_info *si; >+ int i; >+ >+ si = skb_shinfo(skb); >+ >+ for (i = 0; i < si->nr_frags; i++) { >+ skb_frag_t *skb_frag = &si->frags[i]; >+ void *va = page_to_virt(skb_frag->bv_page); >+ >+ /* We will use 'page_to_virt()' for userspace page here, >+ * because virtio layer will call 'virt_to_phys()' later >+ * to fill buffer descriptor. We don't touch memory at >+ * "virtual" address of this page. >+ */ >+ sg_init_one(&bufs[i + 1], >+ va + skb_frag->bv_offset, >+ skb_frag->bv_len); >+ sgs[out_sg++] = &bufs[i + 1]; >+ } >+ } else { >+ if (skb->len > 0) { Should we do the same check (skb->len > 0) for nonlinear skb as well? Or do the nonlinear ones necessarily have len > 0? >+ sg_init_one(&bufs[1], skb->data, skb->len); >+ sgs[out_sg++] = &bufs[1]; >+ } > ^ Blank line that we can remove. Stefano >- sg_init_one(&hdr, virtio_vsock_hdr(skb), sizeof(*virtio_vsock_hdr(skb))); >- sgs[out_sg++] = &hdr; >- if (skb->len > 0) { >- sg_init_one(&buf, skb->data, skb->len); >- sgs[out_sg++] = &buf; > } > > ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, skb, GFP_KERNEL); >-- >2.25.1 >
On 26.06.2023 18:36, Stefano Garzarella wrote: > On Sat, Jun 03, 2023 at 11:49:25PM +0300, Arseniy Krasnov wrote: >> For non-linear skb use its pages from fragment array as buffers in >> virtio tx queue. These pages are already pinned by 'get_user_pages()' >> during such skb creation. >> >> Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru> >> --- >> net/vmw_vsock/virtio_transport.c | 37 ++++++++++++++++++++++++++------ >> 1 file changed, 31 insertions(+), 6 deletions(-) >> >> diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c >> index e95df847176b..6053d8341091 100644 >> --- a/net/vmw_vsock/virtio_transport.c >> +++ b/net/vmw_vsock/virtio_transport.c >> @@ -100,7 +100,9 @@ virtio_transport_send_pkt_work(struct work_struct *work) >> vq = vsock->vqs[VSOCK_VQ_TX]; >> >> for (;;) { >> - struct scatterlist hdr, buf, *sgs[2]; >> + /* +1 is for packet header. */ >> + struct scatterlist *sgs[MAX_SKB_FRAGS + 1]; >> + struct scatterlist bufs[MAX_SKB_FRAGS + 1]; >> int ret, in_sg = 0, out_sg = 0; >> struct sk_buff *skb; >> bool reply; >> @@ -111,12 +113,35 @@ virtio_transport_send_pkt_work(struct work_struct *work) >> >> virtio_transport_deliver_tap_pkt(skb); >> reply = virtio_vsock_skb_reply(skb); >> + sg_init_one(&bufs[0], virtio_vsock_hdr(skb), sizeof(*virtio_vsock_hdr(skb))); >> + sgs[out_sg++] = &bufs[0]; > > Can we use out_sg also to index bufs (here and in the rest of the code)? > > E.g. > > sg_init_one(&bufs[out_sg], ...) > sgs[out_sg] = &bufs[out_sg]; > ++out_sg; > > ... > if (skb->len > 0) { > sg_init_one(&bufs[out_sg], skb->data, skb->len); > sgs[out_sg] = &bufs[out_sg]; > ++out_sg; > } > > etc... > >> + > > For readability, I would move the smaller branch above: > > if (!skb_is_nonlinear(skb)) { > // small block > ... > } else { > // big block > ... > } > >> + if (skb_is_nonlinear(skb)) { >> + struct skb_shared_info *si; >> + int i; >> + >> + si = skb_shinfo(skb); >> + >> + for (i = 0; i < si->nr_frags; i++) { >> + skb_frag_t *skb_frag = &si->frags[i]; >> + void *va = page_to_virt(skb_frag->bv_page); >> + >> + /* We will use 'page_to_virt()' for userspace page here, >> + * because virtio layer will call 'virt_to_phys()' later >> + * to fill buffer descriptor. We don't touch memory at >> + * "virtual" address of this page. >> + */ >> + sg_init_one(&bufs[i + 1], >> + va + skb_frag->bv_offset, >> + skb_frag->bv_len); >> + sgs[out_sg++] = &bufs[i + 1]; >> + } >> + } else { >> + if (skb->len > 0) { > > Should we do the same check (skb->len > 0) for nonlinear skb as well? > Or do the nonlinear ones necessarily have len > 0? Yes, non-linear skb always has 'data_len' > 0, e.g. such skbs always have some data in it. Thanks, Arseniy > >> + sg_init_one(&bufs[1], skb->data, skb->len); >> + sgs[out_sg++] = &bufs[1]; >> + } >> > ^ > Blank line that we can remove. > > Stefano > >> - sg_init_one(&hdr, virtio_vsock_hdr(skb), sizeof(*virtio_vsock_hdr(skb))); >> - sgs[out_sg++] = &hdr; >> - if (skb->len > 0) { >> - sg_init_one(&buf, skb->data, skb->len); >> - sgs[out_sg++] = &buf; >> } >> >> ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, skb, GFP_KERNEL); >> -- >> 2.25.1 >> >
On Tue, Jun 27, 2023 at 07:39:41AM +0300, Arseniy Krasnov wrote: > > >On 26.06.2023 18:36, Stefano Garzarella wrote: >> On Sat, Jun 03, 2023 at 11:49:25PM +0300, Arseniy Krasnov wrote: >>> For non-linear skb use its pages from fragment array as buffers in >>> virtio tx queue. These pages are already pinned by 'get_user_pages()' >>> during such skb creation. >>> >>> Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru> >>> --- >>> net/vmw_vsock/virtio_transport.c | 37 ++++++++++++++++++++++++++------ >>> 1 file changed, 31 insertions(+), 6 deletions(-) >>> >>> diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c >>> index e95df847176b..6053d8341091 100644 >>> --- a/net/vmw_vsock/virtio_transport.c >>> +++ b/net/vmw_vsock/virtio_transport.c >>> @@ -100,7 +100,9 @@ virtio_transport_send_pkt_work(struct work_struct *work) >>> vq = vsock->vqs[VSOCK_VQ_TX]; >>> >>> for (;;) { >>> - struct scatterlist hdr, buf, *sgs[2]; >>> + /* +1 is for packet header. */ >>> + struct scatterlist *sgs[MAX_SKB_FRAGS + 1]; >>> + struct scatterlist bufs[MAX_SKB_FRAGS + 1]; >>> int ret, in_sg = 0, out_sg = 0; >>> struct sk_buff *skb; >>> bool reply; >>> @@ -111,12 +113,35 @@ virtio_transport_send_pkt_work(struct work_struct *work) >>> >>> virtio_transport_deliver_tap_pkt(skb); >>> reply = virtio_vsock_skb_reply(skb); >>> + sg_init_one(&bufs[0], virtio_vsock_hdr(skb), sizeof(*virtio_vsock_hdr(skb))); >>> + sgs[out_sg++] = &bufs[0]; >> >> Can we use out_sg also to index bufs (here and in the rest of the code)? >> >> E.g. >> >> sg_init_one(&bufs[out_sg], ...) >> sgs[out_sg] = &bufs[out_sg]; >> ++out_sg; >> >> ... >> if (skb->len > 0) { >> sg_init_one(&bufs[out_sg], skb->data, skb->len); >> sgs[out_sg] = &bufs[out_sg]; >> ++out_sg; >> } >> >> etc... >> >>> + >> >> For readability, I would move the smaller branch above: >> >> if (!skb_is_nonlinear(skb)) { >> // small block >> ... >> } else { >> // big block >> ... >> } >> >>> + if (skb_is_nonlinear(skb)) { >>> + struct skb_shared_info *si; >>> + int i; >>> + >>> + si = skb_shinfo(skb); >>> + >>> + for (i = 0; i < si->nr_frags; i++) { >>> + skb_frag_t *skb_frag = &si->frags[i]; >>> + void *va = page_to_virt(skb_frag->bv_page); >>> + >>> + /* We will use 'page_to_virt()' for userspace page here, >>> + * because virtio layer will call 'virt_to_phys()' later >>> + * to fill buffer descriptor. We don't touch memory at >>> + * "virtual" address of this page. >>> + */ >>> + sg_init_one(&bufs[i + 1], >>> + va + skb_frag->bv_offset, >>> + skb_frag->bv_len); >>> + sgs[out_sg++] = &bufs[i + 1]; >>> + } >>> + } else { >>> + if (skb->len > 0) { >> >> Should we do the same check (skb->len > 0) for nonlinear skb as well? >> Or do the nonlinear ones necessarily have len > 0? > >Yes, non-linear skb always has 'data_len' > 0, e.g. such skbs always have some >data in it. Okay, makes sense ;-) Thanks, Stefano > >Thanks, Arseniy > >> >>> + sg_init_one(&bufs[1], skb->data, skb->len); >>> + sgs[out_sg++] = &bufs[1]; >>> + } >>> >> ^ >> Blank line that we can remove. >> >> Stefano >> >>> - sg_init_one(&hdr, virtio_vsock_hdr(skb), sizeof(*virtio_vsock_hdr(skb))); >>> - sgs[out_sg++] = &hdr; >>> - if (skb->len > 0) { >>> - sg_init_one(&buf, skb->data, skb->len); >>> - sgs[out_sg++] = &buf; >>> } >>> >>> ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, skb, GFP_KERNEL); >>> -- >>> 2.25.1 >>> >> >
diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c index e95df847176b..6053d8341091 100644 --- a/net/vmw_vsock/virtio_transport.c +++ b/net/vmw_vsock/virtio_transport.c @@ -100,7 +100,9 @@ virtio_transport_send_pkt_work(struct work_struct *work) vq = vsock->vqs[VSOCK_VQ_TX]; for (;;) { - struct scatterlist hdr, buf, *sgs[2]; + /* +1 is for packet header. */ + struct scatterlist *sgs[MAX_SKB_FRAGS + 1]; + struct scatterlist bufs[MAX_SKB_FRAGS + 1]; int ret, in_sg = 0, out_sg = 0; struct sk_buff *skb; bool reply; @@ -111,12 +113,35 @@ virtio_transport_send_pkt_work(struct work_struct *work) virtio_transport_deliver_tap_pkt(skb); reply = virtio_vsock_skb_reply(skb); + sg_init_one(&bufs[0], virtio_vsock_hdr(skb), sizeof(*virtio_vsock_hdr(skb))); + sgs[out_sg++] = &bufs[0]; + + if (skb_is_nonlinear(skb)) { + struct skb_shared_info *si; + int i; + + si = skb_shinfo(skb); + + for (i = 0; i < si->nr_frags; i++) { + skb_frag_t *skb_frag = &si->frags[i]; + void *va = page_to_virt(skb_frag->bv_page); + + /* We will use 'page_to_virt()' for userspace page here, + * because virtio layer will call 'virt_to_phys()' later + * to fill buffer descriptor. We don't touch memory at + * "virtual" address of this page. + */ + sg_init_one(&bufs[i + 1], + va + skb_frag->bv_offset, + skb_frag->bv_len); + sgs[out_sg++] = &bufs[i + 1]; + } + } else { + if (skb->len > 0) { + sg_init_one(&bufs[1], skb->data, skb->len); + sgs[out_sg++] = &bufs[1]; + } - sg_init_one(&hdr, virtio_vsock_hdr(skb), sizeof(*virtio_vsock_hdr(skb))); - sgs[out_sg++] = &hdr; - if (skb->len > 0) { - sg_init_one(&buf, skb->data, skb->len); - sgs[out_sg++] = &buf; } ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, skb, GFP_KERNEL);
For non-linear skb use its pages from fragment array as buffers in virtio tx queue. These pages are already pinned by 'get_user_pages()' during such skb creation. Signed-off-by: Arseniy Krasnov <AVKrasnov@sberdevices.ru> --- net/vmw_vsock/virtio_transport.c | 37 ++++++++++++++++++++++++++------ 1 file changed, 31 insertions(+), 6 deletions(-)