Messages in this thread | | | From | Paul Burton <> | Subject | Re: fs/notify/fanotify/fanotify.c:198:2: note: in expansion of macro 'pr_warn_ratelimited' | Date | Thu, 14 Mar 2019 17:45:00 +0000 |
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Hi Amir,
On Thu, Mar 14, 2019 at 06:16:35PM +0200, Amir Goldstein wrote: > On Thu, Mar 14, 2019 at 4:34 PM Ralf Baechle <ralf@linux-mips.org> wrote: > > On Thu, Mar 14, 2019 at 01:38:11PM +0100, Jan Kara wrote: > > > On Thu 14-03-19 14:01:18, Amir Goldstein wrote: > > > > On Thu, Mar 14, 2019 at 10:37 AM Jan Kara <jack@suse.cz> wrote: > > > > > AFAICS this is the known problem with weird mips definitions of > > > > > __kernel_fsid_t which uses long whereas all other architectures use int, > > > > > right? Seeing that mips can actually have 8-byte longs, I guess this > > > > > bogosity is just wired in the kernel API and we cannot easily fix it in > > > > > mips (mips guys, correct me if I'm wrong). So what if we just > > > > > unconditionally typed printed values to unsigned int to silence the > > > > > warning? > > > > > > > > I don't understand why. To me that sounds like papering over a bug. > > > > > > > > See this reply from mips developer Paul Burton: > > > > https://marc.info/?l=linux-fsdevel&m=154783680019904&w=2 > > > > mips developers have not replied to the question why __kernel_fsid_t > > > > should use long. > > > > > > Ah, right. I've missed that mips defines __kernel_fsid_t only if > > > sizeof(long) == 4. OK, than fixing MIPS headers is definitely what we ought > > > to do. Mips guys, any reason why the patch from Ralf didn't get merged yet? > > > > Paul's patch :-) > > > > As for the reason why the definition is as it is - 32-bit MIPS was > > born using long, then in 2000 64-bit MIPS started off as arch/mips64 > > using int. Eventually the two ports were combined using: > > > > ypedef struct { > > #if (_MIPS_SZLONG == 32) > > long val[2]; > > #endif > > #if (_MIPS_SZLONG == 64) > > int val[2]; > > #endif > > } __kernel_fsid_t; > > > > A desparate attempt to use asm-generic where ever possible then resulted > > in the confusing definition we'e having today. > > > > Normally APIs are cast into stone not to be changed. But fsid is used in > > struct statfs and the man page states "Nobody knows what f_fsid is supposed > > to contain (but see below)." and f_fsid is supposed to be opaque anyway so > > I'm wondering if something could break at all. Researching that. > > > > Its content is opaque, but its size must be equal to that of fsid_t > from glibc/toolchain headers. Do the mips32 glibc headers also > define fsid_t as long val[2], or do they define it as int val[2]?
First off, my apologies that my proposed patch slipped through the cracks. It somehow didn't make it onto my to-do list & after that there was little chance I was going to remember it until someone replied... :)
I've just polished off the patch & submitted it [1]. Presuming nobody has a problem with it in the next couple of days, I'll apply it to mips-fixes & send it on to Linus.
To address your question about glibc headers - it shouldn't matter. On MIPS32 int & long are the same, so even if userland & the kernel disagree about the type the data in memory should be identical.
[1] https://lore.kernel.org/linux-mips/20190314173900.25454-1-paul.burton@mips.com/T/#u
Thanks, Paul
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