Fri, May 08, 2020 at 01:48:20AM CEST, kuba@xxxxxxxxxx wrote: >On Thu, 7 May 2020 18:46:43 +0200 Pablo Neira Ayuso wrote: >> On Thu, May 07, 2020 at 04:49:15PM +0100, Edward Cree wrote: >> > On 07/05/2020 16:32, Pablo Neira Ayuso wrote: >> > > On Thu, May 07, 2020 at 03:59:09PM +0100, Edward Cree wrote: >> > >> Make FLOW_ACTION_HW_STATS_DONT_CARE be all bits, rather than none, so that >> > >> drivers and __flow_action_hw_stats_check can use simple bitwise checks. >> > > >> > > You have have to explain why this makes sense in terms of semantics. >> > > >> > > _DISABLED and _ANY are contradicting each other. >> > No, they aren't. The DISABLED bit means "I will accept disabled", it doesn't >> > mean "I insist on disabled". What _does_ mean "I insist on disabled" is if >> > the DISABLED bit is set and no other bits are. >> > So DISABLED | ANY means "I accept disabled; I also accept immediate or >> > delayed". A.k.a. "I don't care, do what you like". >> >> Jiri said Disabled means: bail out if you cannot disable it. > >That's in TC uAPI Jiri chose... doesn't mean we have to do the same >internally. Yeah, but if TC user says "disabled", please don't assign counter or fail. > >> If the driver cannot disable, then it will have to check if the >> frontend is asking for Disabled (hence, report error to the frontend) >> or if it is actually asking for Don't care. >> >> What you propose is a context-based interpretation of the bits. So >> semantics depend on how you accumulate/combine bits. >> >> I really think bits semantics should be interpreted on the bit alone >> itself. > >These 3 paragraphs sound to me like you were arguing for Ed's approach.. > >> There is one exception though, that is _ANY case, where you let the >> driver pick between delayed or immediate. But if the driver does not >> support for counters, it bails out in any case, so the outcome in both >> request is basically the same. >> >> You are asking for different outcome depending on how bits are >> combined, which can be done, but it sounds innecessarily complicated >> to me. > >No, quite the opposite, the code as committed to net has magic values >which drivers have to check. > >The counter-proposal is that each bit represents a configuration, and >if more than one bit is set the driver gets to choose which it prefers. >What could be simpler? > >netfilter just has to explicitly set the field to DONT_CARE rather than >depending on 0 form zalloc() coinciding with the correct value.
