On Tue, Jan 11, 2022 at 9:35 AM Christoph Hellwig <hch@xxxxxx> wrote:
>
> The fcntl F_GETLK64/F_SETLK64/F_SETLKW64 are only implemented for the
> 32-bit syscall APIs, but we also need them for compat handling on 64-bit
> builds. Redefining them is error prone (as shown by the example that
> parisc gets it wrong currently), so we should use the same defines for
> both case. In theory we could try to hide them from userspace, but
> given that only MIPS actually gets that right, while the asm-generic
> version used by most architectures relies on a Kconfig symbol that can't
> be relied on to be set properly by userspace is a clear indicator to not
> bother.
>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
> diff --git a/include/uapi/asm-generic/fcntl.h b/include/uapi/asm-generic/fcntl.h
> index 98f4ff165b776..43d7c44031be0 100644
> --- a/include/uapi/asm-generic/fcntl.h
> +++ b/include/uapi/asm-generic/fcntl.h
> @@ -116,13 +116,11 @@
> #define F_GETSIG 11 /* for sockets. */
> #endif
>
> -#ifndef CONFIG_64BIT
> #ifndef F_GETLK64
> #define F_GETLK64 12 /* using 'struct flock64' */
> #define F_SETLK64 13
> #define F_SETLKW64 14
> #endif
> -#endif
>
> #ifndef F_SETOWN_EX
> #define F_SETOWN_EX 15
This is a very subtle change to the exported UAPI header contents:
On 64-bit architectures, the three unusable numbers are now always
shown, rather than depending on a user-controlled symbol.
This is probably what we want here for compatibility reasons, but I think
it should be explained in the changelog text, and I'd like Jeff or Bruce
to comment on it as well: the alternative here would be to make the
uapi definition depend on __BITS_PER_LONG==32, which is
technically the right thing to do but more a of a change.
Arnd
