David Laight [off-list ref] writes:

From: Bjørn Mork
...

quoted

quoted

Since you are now copying the data out of the URB's skb before
passing the ethernet packet upstream, is there ever any real
requirement to use a small rx_max? or ever change rx_max?

Yes.  usbnet doesn't currently recycle skbs.  Continuously allocating 32
kB skbs (or even 64 kB truesize, which is the current cdc_ncm worst
case) on memory constrained hosts is bound to fail eventually.

Getting usbnet to recycle skb shouldn't be too hard - and will
be an immediate gain for most of the drivers.

Yes.  This is one of those problems that really isn't that hard to
solve.  Until you start hitting all the corner cases...  But I'm sure it
is doable.

Anyway, it is not going to be part of this patch series, which is merely
touching the cdc_ncm minidriver within the existing usbnet framework.


Bjørn