[lwip-devel] [patch #5453] pbuf patch for SYS_LIGHTWEIGHT_PROT=0

[Simon Goldschmidt]

Follow-up Comment #16, patch #5453 (project lwip):

To get back to the original meaning of this patch: we have decided that
SYS_LIGHTWEIGHT_PROT=0 means no protection.

The current pbuf.c implementation locks a task and interrupt context from
concurrent access to pbuf_alloc (in this special case, a variable is enough
as long as interrupts do not pre-empt each other). But it does _not_ lock
pbuf_alloc() against pbuf_free(). Also it uses a semaphore in pbuf_free()
with SYS_LIGHTWEIGHT_PROT=0 (which is the absolute opposite of pbuf_alloc()
:)

So we decided to remove the current SYS_LIGHTWEIGHT_PROT=0 code, since we
said SYS_LIGHTWEIGHT_PROT=0 stands for _no_ locking at all (everything in a
big loop).

I'm attaching a patch for this.

(file #12531)
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Additional Item Attachment:

File name: pbuf_lightweightprot.patch     Size:8 KB


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