Re: [PATCH 1/2] hw/net/net_tx_pkt: add function to check pkt->max_raw_frags

[Jason Wang]

On 2020/7/29 上午12:26, Mauro Matteo Cascella wrote:
On Tue, Jul 28, 2020 at 6:06 AM Jason Wang <jasow...@redhat.com> wrote:

On 2020/7/28 上午1:08, Mauro Matteo Cascella wrote:
This patch introduces a new function in hw/net/net_tx_pkt.{c,h} to check the
current data fragment against the maximum number of data fragments.

I wonder whether it's better to do the check in
net_tx_pkt_add_raw_fragment() and fail there.
Given the assertion, I assumed the caller is responsible for the
check, but moving the check in net_tx_pkt_add_raw_fragment() totally
makes sense to me.


Want to send a new version for this?



Btw, I find net_tx_pkt_add_raw_fragment() does not unmap dma when
returning to true, is this a bug?
Isn't it unmapped in net_tx_pkt_reset()?


Probably but see how it was used in e1000e, the net_tx_pkt_reset() is 
only called when eop is set. Is this a bug?

Thanks


Thanks


Reported-by: Ziming Zhang <ezrak...@gmail.com>
Signed-off-by: Mauro Matteo Cascella <mcasc...@redhat.com>
---
   hw/net/net_tx_pkt.c | 5 +++++
   hw/net/net_tx_pkt.h | 8 ++++++++
   2 files changed, 13 insertions(+)

diff --git a/hw/net/net_tx_pkt.c b/hw/net/net_tx_pkt.c
index 9560e4a49e..d035618f2c 100644
--- a/hw/net/net_tx_pkt.c
+++ b/hw/net/net_tx_pkt.c
@@ -400,6 +400,11 @@ bool net_tx_pkt_add_raw_fragment(struct NetTxPkt *pkt, 
hwaddr pa,
       }
   }

+bool net_tx_pkt_exceed_max_fragments(struct NetTxPkt *pkt)
+{
+    return pkt->raw_frags >= pkt->max_raw_frags;
+}
+
   bool net_tx_pkt_has_fragments(struct NetTxPkt *pkt)
   {
       return pkt->raw_frags > 0;
diff --git a/hw/net/net_tx_pkt.h b/hw/net/net_tx_pkt.h
index 4ec8bbe9bd..e2ee46ae03 100644
--- a/hw/net/net_tx_pkt.h
+++ b/hw/net/net_tx_pkt.h
@@ -179,6 +179,14 @@ bool net_tx_pkt_send_loopback(struct NetTxPkt *pkt, 
NetClientState *nc);
    */
   bool net_tx_pkt_parse(struct NetTxPkt *pkt);

+/**
+* indicates if the current data fragment exceeds max_raw_frags
+*
+* @pkt:            packet
+*
+*/
+bool net_tx_pkt_exceed_max_fragments(struct NetTxPkt *pkt);
+
   /**
   * indicates if there are data fragments held by this packet object.
   *