RE: [PATCH] blk-iocost: fix seq_printf compile type mismatch error

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



From: Tejun Heo
> Sent: 20 July 2023 21:07
> 
> On Wed, Jul 19, 2023 at 08:57:32AM +0000, David Laight wrote:
> > From: Tejun Heo
> > > Sent: 17 July 2023 19:49
> > >
> > > On Mon, Jul 17, 2023 at 09:18:52AM -0500, Carlos Bilbao wrote:
> > > > From: amd <amd@localhost.localdomain>
> > > >
> > > > Fix two type mismatch errors encountered while compiling blk-iocost.c with
> > > > GCC version 13.1.1 that involved constant operator WEIGHT_ONE. Cast the
> > > > result of the division operation to (unsigned int) to match the expected
> > > > format specifier %u in two seq_printf invocations.
> > >
> > > Can you detail the warnings? Was that on 32bit compiles?
> >
> > The problem is caused by gcc 13 changing the types of the
> > constants inside an enum to be all the same.
> >
> > The best fix is (probably) to replace all the enum used to
> > define unrelated constants with #defines.
> 
> Yeah, but then you end up without any way to read that value from outside
> the kernel for BPF, drgn or any other tools which use debug info. That
> actually matters.

Some of those constants (probably including the one that forces
the enum to 'long' are very boring.
I don't remember which one caused the change, but some were
similar to 'microseconds in a second'.

In any case it is enough to split the enum.
If you really need unrelated constants to be defined in an enum
them maybe use a separate enum for each.
Using (on one line):
	enum { name = constant };
may work best.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)




[Index of Archives]     [Linux RAID]     [Linux SCSI]     [Linux ATA RAID]     [IDE]     [Linux Wireless]     [Linux Kernel]     [ATH6KL]     [Linux Bluetooth]     [Linux Netdev]     [Kernel Newbies]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Device Mapper]

  Powered by Linux