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splice, net: Handle MSG_SPLICE_PAGES in AF_KCM
Here are patches to make AF_KCM handle the MSG_SPLICE_PAGES internal
sendmsg flag. MSG_SPLICE_PAGES is an internal hint that tells the protocol
that it should splice the pages supplied if it can. Its sendpage
implementation is then turned into a wrapper around that.
Does anyone actually use AF_KCM? Upstream it has some issues. It doesn't
seem able to handle a "message" longer than 113920 bytes without jamming
and doesn't handle the client termination once it is jammed.