Re: [PATCH net-next v4 3/6] vhost/vsock: support MSG_EOR bit processing

From: Stefano Garzarella
Date: Fri Sep 03 2021 - 02:55:48 EST


On Fri, Sep 03, 2021 at 09:15:38AM +0300, Arseny Krasnov wrote:
'MSG_EOR' handling has similar logic as 'MSG_EOM' - if bit present
in packet's header, reset it to 0. Then restore it back if packet
processing wasn't completed. Instead of bool variable for each
flag, bit mask variable was added: it has logical OR of 'MSG_EOR'
and 'MSG_EOM' if needed, to restore flags, this variable is ORed
with flags field of packet.

Signed-off-by: Arseny Krasnov <arseny.krasnov@xxxxxxxxxxxxx>
---
drivers/vhost/vsock.c | 22 +++++++++++++---------
1 file changed, 13 insertions(+), 9 deletions(-)

diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index feaf650affbe..93e8d635e18f 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -114,7 +114,7 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
size_t nbytes;
size_t iov_len, payload_len;
int head;
- bool restore_flag = false;
+ u32 flags_to_restore = 0;

spin_lock_bh(&vsock->send_pkt_list_lock);
if (list_empty(&vsock->send_pkt_list)) {
@@ -179,15 +179,20 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
* created dynamically and are initialized with header
* of current packet(except length). But in case of
* SOCK_SEQPACKET, we also must clear message delimeter
- * bit(VIRTIO_VSOCK_SEQ_EOM). Otherwise, instead of one
- * packet with delimeter(which marks end of message),
- * there will be sequence of packets with delimeter
- * bit set. After initialized header will be copied to
- * rx buffer, this bit will be restored.
+ * bit (VIRTIO_VSOCK_SEQ_EOM) and MSG_EOR bit
+ * (VIRTIO_VSOCK_SEQ_EOR) if set. Otherwise,
+ * there will be sequence of packets with these
+ * bits set. After initialized header will be copied to
+ * rx buffer, these required bits will be restored.
*/
if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SEQ_EOM) {
pkt->hdr.flags &= ~cpu_to_le32(VIRTIO_VSOCK_SEQ_EOM);
- restore_flag = true;
+ flags_to_restore |= VIRTIO_VSOCK_SEQ_EOM;
+
+ if (le32_to_cpu(pkt->hdr.flags & VIRTIO_VSOCK_SEQ_EOR)) {
+ pkt->hdr.flags &= ~cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR);
+ flags_to_restore |= VIRTIO_VSOCK_SEQ_EOR;
+ }
}
}

@@ -224,8 +229,7 @@ vhost_transport_do_send_pkt(struct vhost_vsock *vsock,
* to send it with the next available buffer.
*/
if (pkt->off < pkt->len) {
- if (restore_flag)
- pkt->hdr.flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOM);
+ pkt->hdr.flags |= cpu_to_le32(flags_to_restore);

/* We are queueing the same virtio_vsock_pkt to handle
* the remaining bytes, and we want to deliver it
--
2.25.1


Reviewed-by: Stefano Garzarella <sgarzare@xxxxxxxxxx>