On Mon, Nov 22, 2010 at 6:40 PM, Arnaud Lacombe <lacombar@xxxxxxxxx> wrote: > Hi, > > On Mon, Nov 22, 2010 at 9:32 PM, Luis R. Rodriguez > <lrodriguez@xxxxxxxxxxx> wrote: >> On Mon, Nov 22, 2010 at 6:19 PM, Arnaud Lacombe <lacombar@xxxxxxxxx> wrote: >>> Hi, >>> >>> On Mon, Nov 22, 2010 at 1:09 PM, Luis R. Rodriguez >>> <lrodriguez@xxxxxxxxxxx> wrote: >>>> On Sun, Nov 21, 2010 at 5:36 PM, Arnaud Lacombe <lacombar@xxxxxxxxx> wrote: >>>>> [...] >>>>> The compat headers should be at the end of the include list, so that >>>>> the kernel headers get included first, and the compat one will only be >>>>> when the kernel does not provide the header. This is the only sane way >>>>> to override kernel provided stuff. That said, there is certainly a >>>>> use-case I missed. >>>> >>>> Agreed, but you are missing the purpose of the trick used here. >>> certainly :) >>> >>>> The >>>> purpose of the include_next was so that we can name our own >>>> <linux/pm_qos_params.h> which is part of compat and these directories >>>> *will* get a priority over the kernel's so that way we can avoid >>>> ifdef'ing all includes for the same file on the upstream code. >>> I'm not sure to get what you mean by "we can avoid ifdef'ing all >>> includes for the same file on the upstream code", can you details ? >> >> Ah, that's right, you don't see or use compat-wireless likely. Ok, so >> what we do for backporting the 802.11 subsystem, Bluetooth and some >> Ethernet drivers is we take the stock upstream files, stuff them into >> a new directory, and then apply a series of patches to them to get the >> files to properly compile. The patches address all things that was not >> possible to backport through compat.git. Header file changes is one of >> the typical things we run into. If a new header file is added to newer >> kernels we can play a hack for older kernels and leave the code intact >> and introduce our own include/linux/foo.h through compat by prefering >> the local path over the kernel's path. If we're on newer kernels >> though include_next will go on the search path and find the kernel's >> own header file. >> > Is there any reason you want the compat's include directory to be > *before* the kernel include directory ? Hm, yeah but I forget why. It'll come to me. > Because just considering this > issue, if the kernel include directory was seen first, this would not > arise, as the compat-provided header would just be a fallback. True. Luis -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
