bizarre em + TSO + MSS issue in RELENG_7
pyunyh at gmail.com
Sat Nov 17 22:06:45 PST 2007
On Sat, Nov 17, 2007 at 10:00:16PM -0800, Jack Vogel wrote:
> > It seems that em_tso_setup() doesn't clear txd_upper/txd_lower in
> > failure path so that unintialized value could be used in subsequent
> > Tx descriptor setup.
> > How about clearing those variable?(Patch attached)
> > It seems that em(4) uses EM_TSO_SIZE(64K) to create DMA tag. A packet
> > can have 64K payload under TSO so its the mximum size of the mbuf
> > chain would be 64K + sizeof(link layer). So I guess the EM_TSO_SIZE
> > should be increased to hold sizeof(link layer).
> > It had been a long time since I looked into em(4) so I'm not sure.
> Huh? They are set to 0 on entry, and not touched again before you go
> into the setup routine, your change has no effect.
Sorry for the noise.
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