Re: [PATCH] MIPS: Remove custom MIPS32 __kernel_fsid_t type

[Paul Burton]

Hello,

Paul Burton wrote:
> For MIPS32 kernels we have a custom definition of __kernel_fsid_t. This
> differs from the asm-generic version used by all other architectures &
> MIPS64 in one way - it declares the val field as an array of long,
> rather than an array of int. Since int & long have identical size &
> alignment when targeting MIPS32 anyway, this makes little sense.
> 
> Beyond the pointlessness this causes problems for code which prints
> entries from the val array, for example the fanotify_encode_fid()
> function [1]. If such code uses a format specified suited to an int then
> it encounters compiler warnings when building for MIPS32, such as:
> 
> In file included from include/linux/kernel.h:14:0,
> from include/linux/list.h:9,
> from include/linux/preempt.h:11,
> from include/linux/spinlock.h:51,
> from include/linux/fdtable.h:11,
> from fs/notify/fanotify/fanotify.c:3:
> fs/notify/fanotify/fanotify.c: In function 'fanotify_encode_fid':
> include/linux/kern_levels.h:5:18: warning: format '%x' expects argument
> of type 'unsigned int', but argument 2 has type 'long int' [-Wformat=]
> 
> Remove the custom __kernel_fsid_t definition & make use of the
> asm-generic version which will have an identical layout in memory
> anyway, in order to remove the inconsistency with other architectures.
> 
> One possible regression this could cause if is any code is attempting to
> print entries from the val array with a long-sized format specifier, in
> which case it would begin seeing compiler warnings when built against
> kernel headers including this change. Since such code is exceedingly
> rare, and would have to be MIPS32-specific to expect a long, this seems
> to be a problem that it's extremely unlikely anyone will encounter.
> 
> [1] https://lore.kernel.org/linux-mips/CAOQ4uxiEkczB7PNCXegFC-eYb9zAGaio_o=OgHAJHFd7eavBxA@xxxxxxxxxxxxxx/T/#mb43103277c79ef06b884359209e817db1c136140
> 
> Signed-off-by: Paul Burton <paul.burton@xxxxxxxx>
> Cc: Amir Goldstein <amir73il@xxxxxxxxx>
> Cc: Arnd Bergmann <arnd@xxxxxxxx>
> Cc: Jan Kara <jack@xxxxxxx>
> Cc: linux-arch@xxxxxxxxxxxxxxx
> Cc: linux-mips@xxxxxxxxxxxxxxx

Applied to mips-fixes.

Thanks,
    Paul

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