Messages in this thread | | | Date | Mon, 19 Jan 2009 09:55:22 -0800 | From | Randy Dunlap <> | Subject | Re: mmotm 2009-01-14-20-31 uploaded (gfs2) |
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Steven Whitehouse wrote: > Hi, > > On Mon, 2009-01-19 at 09:05 -0800, Randy Dunlap wrote: >> Steven Whitehouse wrote: >>> Hi, >>> >>> On Fri, 2009-01-16 at 09:35 -0800, Andrew Morton wrote: >>>> On Fri, 16 Jan 2009 09:06:23 -0800 Randy Dunlap <randy.dunlap@oracle.com> wrote: >>>> >>>>>>>> which is not ideal, but I don't see any easy way to avoid the #ifdef, >>>>>>>> >>>>>>> Take a look in fs.h: >>>>>>> >>>>>>> #define generic_setlease(a, b, c) ({ -EINVAL; }) >>>>>>> >>>>>>> If that wasn't a stupid macro, your code would have compiled and ran >>>>>>> just as intended. >>>>>>> >>>>>> There doesn't seem to be an easy answer though. If I #define it to NULL, >>>>>> that upsets other parts of the code that rely on that macro, and if I >>>>>> turn it into a inline function which returns -EINVAL, then presumably I >>>>>> can't take its address for my file_operations. >>>>> No, gcc will allow &inline_func and out-of-line it if it is needed (AFAIK; >>>>> I've seen a few cases of that). >>>>> >>>> yup. It measn that we'll get a separate private copy of the >>>> generic_setlease() code in each compilation unit which takes its >>>> address, but I don't think that would kill us. >>>> >>>> The prevention is of course to put the stub function in a core kernel >>>> .c file and export it to modules. >>>> >>> Having looked into this in a bit more detail now, it seems that this >>> particular function (generic_setlease) is one of a number appearing in >>> fs.h which are replaced by macros in the case that CONFIG_FILE_LOCKING >>> is not set. >>> >>> So rather than just do the one function, it seemed to make sense to me >>> to make them all the same. So this uses inline functions as originally >>> proposed. If you'd prefer that we don't inline them and instead have a >>> fs/no-locks.c or something like that with stub functions in it, then I"m >>> happy to revise the patch accordingly. >> Acked-by/Tested-by: Randy Dunlap <randy.dunlap@oracle.com> >> > Ok, Thanks. I'll send a proper patch to a suitable tree. Presumably the > VFS tree would be best for this?
That sounds correct, but no guarantees.
>>> This patch passes my compile tests, modulo a small change that I need to >>> make in GFS2 to suppress a warning (not attached). That seems to be >>> related to yet another set of macros which appear only with >>> CONFIG_FILE_LOCKING not set. Maybe I should update those to be inline >>> functions as well.... >> You mean these? Probably should update them as well. >> >> #else /* !CONFIG_FILE_LOCKING */ >> #define locks_mandatory_locked(a) ({ 0; }) >> #define locks_mandatory_area(a, b, c, d, e) ({ 0; }) >> #define __mandatory_lock(a) ({ 0; }) >> #define mandatory_lock(a) ({ 0; }) >> #define locks_verify_locked(a) ({ 0; }) >> #define locks_verify_truncate(a, b, c) ({ 0; }) >> #define break_lease(a, b) ({ 0; }) >> #endif /* CONFIG_FILE_LOCKING */ >> >> > Yes, I'll do a patch for those as well then,
Thanks.
-- ~Randy
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