> > Hey Konstantin, > > > > On Mon, May 13, 2019 at 10:49:00AM +0000, Ananyev, Konstantin wrote: > > > Hi Adrien, > > > > > > > > > > > On Mon, May 13, 2019 at 09:51:24AM +0000, Smoczynski, MarcinX > wrote: > > > > > 10/05/2019 20:17, Thomas Monjalon: > > > > > > 10/05/2019 19:14, Smoczynski, MarcinX: > > > > > > > To summarize we have different visibility sets for Linux and > > > > > > > BSD when using XOPEN_SOURCE or POSIX_C_SOURCE explicitly. > To > > > > > > > overcome this situation we can either remove problematic > > > > > > > XOPEN macros from mk/meson rules (drivers/net/failsafe, > > > > > > > drivers/net/mlx4, > > > > > > > drivers/net/mlx5) > > > > > > > > > > > > What is the consequence of removing these macros in mlx and > failsafe PMDs? > > > > > > > > > > The purpose of these *_SOURCE constants is to enable particular > > > > > feature sets visibility. As long as we have GNU_SOURCE on Linux > > > > > removing it won't have any consequences. On BSD it will unify > > > > > feature sets visibility with the rest of sources. Can't think of any > downsides here. > > > > > > > > > > I believe XOPEN_SOURCE was introduced to extend features not to > restrict them. > > > > > > > > I confirm that under Linux, all IPPROTO_* (POSIX/XOPEN/RFC1700) > > > > are defined regardless (_GNU_SOURCE not even needed), while under > > > > FreeBSD, the non-POSIX versions are only defined when > __BSD_VISIBLE is set. > > > > > > > > The FreeBSD behavior is more correct in this respect since the > > > > purpose of _XOPEN_SOURCE and friends is also to let applications > > > > limit the risk of redefinitions in case they were written for an > > > > earlier standard (e.g. -D_XOPEN_SOURCE=500 vs. - > D_XOPEN_SOURCE=600). > > > > > > Still not sure why do you need it for failsafe and mlx PMDs? > > > Would something in these PMDs be broken without '- > D_XOPEN_SOURCE=600'? > > > > Well, not really. At least not anymore if they compile fine without it > > on all supported targets. I don't mind if they are removed from PMDs. > > > > _XOPEN_SOURCE=600 was originally added to mlx4 (later inherited by > > mlx5 and > > failsafe) for the following reasons: > > > > - Out fo habit, since a lot of stuff in unistd.h and fcntl.h depends on it > > to be exposed. Some affected definitions were likely needed at some > point. > > > > - Besides toggling C syntax extensions, forcing a C standard through the > > -std parameter (e.g. -std=c99) in order to guarantee a minimum level of > > C compliance disables the implicit presence of nonstandard definitions, > > which must be re-enabled as needed through the appropriate #defines. > > > > For instance, including unistd.h for getsid() stops working as soon as > > you use -std=c99. On Linux you can get it back through -std=gnu99 or > > by combining -std=c99 with -D_GNU_SOURCE or -D_XOPEN_SOURCE. The > > latter was chosen because it is the standard define supposed to work > across OSes. > > > > Historically mlx4 had to enable -std=c99 to be able to use various > > features not present when GCC defaulted to -std=gnu90. It was later > > transformed to > > -std=c11 for similar reasons (anonymous members in structs/unions if > > memory serves me right). > > > > > > DPDK applications may also define _XOPEN_SOURCE for their own > > > > needs. They should still be able to use rte_ip.h afterward. > > > > > > I suppose they can, they would just have (on FreeBSD) to add '-D > __BSD_VISIBLE' > > > themselves. > > > > Of course, but public headers should be as self sufficient as possible. > > Unless they provide really insane compiler flags, if user applications > > get compilation errors after including some header we install on the > > system, I think the blame is on DPDK. > > > > > > I think this reason is > > > > enough to go with -D__BSD_VISIBLE under FreeBSD without removing > > > > _XOPEN_SOURCE, as it should work regardless. > > > > > > So do you suggest to add '-D __BSD_VISIBLE' into mlx/failsafe PMDs > > > Makefiles/meson.build, or ... ? > > > > Since headers of our public API potentially require it, it must be > > defined globally (unlike _XOPEN_SOURCE which is only local to a few > PMDs): > > app/meson.build, lib/meson.build, mk/target/generic/rte.vars.mk, > > alongside -D_GNU_SOURCE. > > > > Add it to mlx*/failsafe only if that's not enough. Just make sure > > applications inherit this flag. > > Ok, to summarize, eyour suggestion is: > 1. remove -D_XOPEN_SOURCE=... from mlx and failsafe PMDs. > 2. add '-D __BSD_VISIBLE' into top level make/meson files > (app/meson.build, lib/meson.build, mk/target/generic/rte.vars.mk) Similar > to what we doing for -DGNU_SOURCE. > > If I understand you correctly, then it sounds ok to me. > > > > > > > Looking at the patch [1], I also think there's another, simpler > > > > approach: > > > > unless really performance critical, defining > > > > rte_ipv6_get_next_ext() in rte_net.c instead of a static inline in > rte_ip.h should address this issue. > > > > > > It is performance critical, and I think that function call for each > > > ext header is a way too expensive approach. > > > Will prefer to keep that function inline. > > > > OK, a bit cumbersome but since we're heading this way [2], how about > > defining our own instead of all the above? > > > > #define RTE_IPPROTO_HOPOPTS 0 > > #define RTE_IPPROTO_ROUTING 43 > > ... > > > > Which could prove handy later as it appears Linux and FreeBSD don't > > have the same set of available IPPROTO_* definitions. > > > > Thoughts? > > > > [2] "[RFC v2 00/14] prefix network structures" > > https://mails.dpdk.org/archives/dev/2019-April/129752.html > > Yep, that's definitely an option too. > But if we going to replace all current references of IPPROTO_ inside DPDK to > RTE_IPROTO_ - the change will be massive. > And for sure it is out of scope of this patch series. > That's probably need to be done after Olivier RFC will be in and should be > subject of a separate patch series. > Konstantin
I agree that we need RTE_IPPROTO* macros but as Konstantin pointed out this would be a huge change and we should do that on top of Oliver's work in a separate patch set. I will propose a patch set with: 1. Removed XOPEN_SOURCE macros as they are not needed anymore 2. Added BSD_VISIBLE at the top of build system. Thanks for your comments, Marcin.
