On Mon, Mar 25, 2013 at 4:58 PM, Wei Liu [off-list ref] wrote:

So it is a bit tricky here. Let me clarify this, the head field is
used to indicate the start of a new tx requests queue and the end of
previous queue.

Imagine a sequence of head fileds(I = INVALID_PENDING_RING_IDX below),
the number is the starting index of pending ring.

  .... 0 I I I 5 I I ...

consume all tx_info but not setting I to 0 (or any number other then
I) makes the sequence remains the same as before. The in subsequent
call to process next SKB, which has 3 extra slots, which makes the

Sorry, should be "4 extra slots"

sequence looks like

  .... 8 | | | | | | ...

but in fact the correct sequence should be

  .... 8 | | | | 0 0 ...


Wei.