* Ram Pai <linuxram@xxxxxxxxxx> wrote:
> Once an address range is associated with an allocated pkey, it cannot be
> reverted back to key-0. There is no valid reason for the above behavior. On
> the contrary applications need the ability to do so.
>
> The patch relaxes the restriction.
>
> Tested on powerpc and x86_64.
>
> cc: Dave Hansen <dave.hansen@xxxxxxxxx>
> cc: Michael Ellermen <mpe@xxxxxxxxxxxxxx>
> cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Signed-off-by: Ram Pai <linuxram@xxxxxxxxxx>
> ---
> arch/powerpc/include/asm/pkeys.h | 19 ++++++++++++++-----
> arch/x86/include/asm/pkeys.h | 5 +++--
> 2 files changed, 17 insertions(+), 7 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/pkeys.h b/arch/powerpc/include/asm/pkeys.h
> index 0409c80..3e8abe4 100644
> --- a/arch/powerpc/include/asm/pkeys.h
> +++ b/arch/powerpc/include/asm/pkeys.h
> @@ -101,10 +101,18 @@ static inline u16 pte_to_pkey_bits(u64 pteflags)
>
> static inline bool mm_pkey_is_allocated(struct mm_struct *mm, int pkey)
> {
> - /* A reserved key is never considered as 'explicitly allocated' */
> - return ((pkey < arch_max_pkey()) &&
> - !__mm_pkey_is_reserved(pkey) &&
> - __mm_pkey_is_allocated(mm, pkey));
> + /* pkey 0 is allocated by default. */
> + if (!pkey)
> + return true;
> +
> + if (pkey < 0 || pkey >= arch_max_pkey())
> + return false;
> +
> + /* reserved keys are never allocated. */
> + if (__mm_pkey_is_reserved(pkey))
> + return false;
Please capitalize in comments consistently, i.e.:
/* Reserved keys are never allocated: */
> +
> + return(__mm_pkey_is_allocated(mm, pkey));
'return' is not a function.
Thanks,
Ingo
