Messages in this thread | | | Subject | Re: mmotm 2009-01-14-20-31 uploaded (gfs2) | From | Steven Whitehouse <> | Date | Mon, 19 Jan 2009 17:27:30 +0000 |
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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?
> > 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,
Steve.
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