On Tue, 30 Oct 2007, Randy Dunlap wrote: > drivers/media/video/bt8xx/bttv-cards.c calls ip_compute_csum(). > However, when CONFIG_NET=n, that produces: > > ERROR: "ip_compute_csum" [drivers/media/video/bt8xx/bttv.ko] undefined! > > Config symbol VIDEO_BT848 can be made to depend on NET, or the > osprey_eeprom() function can be built depending on some new config > symbol, or bttv could have its own checksum function...
The real problem here is that ip_compute_csum is part of lib-y, but is also exported for modules. This problem has come up before, for instance your patch for csum_partial() http://lkml.org/lkml/2007/4/3/209 Or the problem with kasprintf and the lg module: http://lkml.org/lkml/2007/9/24/15 The general lib-y vs EXPORT_SYMBOL problem: http://lkml.org/lkml/2007/9/25/17 The only reason the net stuff works, is because CONFIG_NET includes igmp.c, which can't be compiled as a module. That means ip_compute_csum() will get pulled out of the lib.a file for igmp, and thus be present for the net modules that use it too. If igmp could be turned off, made a module, or stopped using ip_compute_csum(), then the users of ip_compute_csum() that do depend on CONFIG_NET would have the same problem as bttv does. It seems a shame to create a new ip checksum function in the bttv driver when a perfectly good one already exists and will already be present in just about every kernel out there. Honestly, how common is NET=n and VIDEO_BT848=m outside of randconfig? - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
