On 06.11.2022 22:50, Christophe JAILLET wrote:
> Le 06/11/2022 à 20:36, Arseniy Krasnov a écrit :
>> To support zerocopy receive, packet's buffer allocation is changed: for
>> buffers which could be mapped to user's vma we can't use 'kmalloc()'(as
>> kernel restricts to map slab pages to user's vma) and raw buddy
>> allocator now called. But, for tx packets(such packets won't be mapped
>> to user), previous 'kmalloc()' way is used, but with special flag in
>> packet's structure which allows to distinguish between 'kmalloc()' and
>> raw pages buffers.
>>
>> Signed-off-by: Arseniy Krasnov <AVKrasnov@xxxxxxxxxxxxxx>
>> ---
>> drivers/vhost/vsock.c | 1 +
>> include/linux/virtio_vsock.h | 1 +
>> net/vmw_vsock/virtio_transport.c | 8 ++++++--
>> net/vmw_vsock/virtio_transport_common.c | 10 +++++++++-
>> 4 files changed, 17 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
>> index 5703775af129..65475d128a1d 100644
>> --- a/drivers/vhost/vsock.c
>> +++ b/drivers/vhost/vsock.c
>> @@ -399,6 +399,7 @@ vhost_vsock_alloc_pkt(struct vhost_virtqueue *vq,
>> return NULL;
>> }
>> + pkt->slab_buf = true;
>> pkt->buf_len = pkt->len;
>> nbytes = copy_from_iter(pkt->buf, pkt->len, &iov_iter);
>> diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
>> index 35d7eedb5e8e..d02cb7aa922f 100644
>> --- a/include/linux/virtio_vsock.h
>> +++ b/include/linux/virtio_vsock.h
>> @@ -50,6 +50,7 @@ struct virtio_vsock_pkt {
>> u32 off;
>> bool reply;
>> bool tap_delivered;
>> + bool slab_buf;
>> };
>> struct virtio_vsock_pkt_info {
>> diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
>> index ad64f403536a..19909c1e9ba3 100644
>> --- a/net/vmw_vsock/virtio_transport.c
>> +++ b/net/vmw_vsock/virtio_transport.c
>> @@ -255,16 +255,20 @@ static void virtio_vsock_rx_fill(struct virtio_vsock *vsock)
>> vq = vsock->vqs[VSOCK_VQ_RX];
>> do {
>> + struct page *buf_page;
>> +
>> pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
>> if (!pkt)
>> break;
>> - pkt->buf = kmalloc(buf_len, GFP_KERNEL);
>> - if (!pkt->buf) {
>> + buf_page = alloc_page(GFP_KERNEL);
>> +
>> + if (!buf_page) {
>> virtio_transport_free_pkt(pkt);
>> break;
>> }
>> + pkt->buf = page_to_virt(buf_page);
>> pkt->buf_len = buf_len;
>> pkt->len = buf_len;
>> diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>> index a9980e9b9304..37e8dbfe2f5d 100644
>> --- a/net/vmw_vsock/virtio_transport_common.c
>> +++ b/net/vmw_vsock/virtio_transport_common.c
>> @@ -69,6 +69,7 @@ virtio_transport_alloc_pkt(struct virtio_vsock_pkt_info *info,
>> if (!pkt->buf)
>> goto out_pkt;
>> + pkt->slab_buf = true;
>> pkt->buf_len = len;
>> err = memcpy_from_msg(pkt->buf, info->msg, len);
>> @@ -1339,7 +1340,14 @@ EXPORT_SYMBOL_GPL(virtio_transport_recv_pkt);
>> void virtio_transport_free_pkt(struct virtio_vsock_pkt *pkt)
>> {
>> - kvfree(pkt->buf);
>> + if (pkt->buf_len) {
>> + if (pkt->slab_buf)
>> + kvfree(pkt->buf);
>
> Hi,
>
> kfree()? (according to virtio_transport_alloc_pkt() in -next) or something else need to be changed.
>
Hello Cristophe,
I think, 'kvfree()' is still needed here, because buffer for packet could be allocated by 'kvmalloc()'
in drivers/vhost/vsock.c. Correct me if i'm wrong.
>> + else
>> + free_pages((unsigned long)pkt->buf,
>> + get_order(pkt->buf_len));
>
> In virtio_vsock_rx_fill(), only alloc_page() is used.
>
> Should this be alloc_pages(.., get_order(buf_len)) or free_page() (without an 's') here?
This function frees packets which were allocated in vhost path also. In vhost, for zerocopy
packets alloc_pageS() is used.
Thank You, Arseniy
>
> Just my 2c,
>
> CJ
>
>> + }
>> +
>> kfree(pkt);
>> }
>> EXPORT_SYMBOL_GPL(virtio_transport_free_pkt);
>
