[lwip-devel] [patch #7658] Make pbuf_free() send PBUF_POOL pbufs to Ethernet driver directly.

[James Smith]

Follow-up Comment #2, patch #7658 (project lwip):

I noticed this patch request, and that it has not been acted on for a while,
and since we need (use) similar functionality I thought it prudent to add to
this existing patch in the hope of reviving it, instead of creating a new
(competing) patch.

Similarly for our driver support we need a hook to allow PBUF_POOL entries to
be returned to the driver in a timely fashion, and ideally avoiding
unnecessary free/alloc operations.

Attached is a suggested patch (against the head of the git tree) implementing
the support slightly differently to that originally suggested last year by
Timothy in his original comment.

Basically I used a more generic (in my opinion) manifest name of
PBUF_POOL_FREE_HOOK (instead of DMA_RING_REPLENISH) and the polarity of the
"return" code is changed to 0 means re-used, and 1 means pbuf_free() can
continue to release the allocation (that way around made it easier/simpler
ensuring that the pbuf_free() "count" is maintained with minimum overhead).

A new routine pbuf_pool_reinit() is provided to allow the callback (if
defined) to reset the PBUF state. Some assumptions are covered by asserts.



(file #25968)
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File name: pbuf_7658.patch                Size:6 KB


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