Gregory Price <gourry.memverge@xxxxxxxxx> writes:
> split sanitize_mpol_flags into sanitize and validate.
>
> Sanitize is used by set_mempolicy to split (int mode) into mode
> and mode_flags, and then validates them.
>
> Validate validates already split flags.
>
> Validate will be reused for new syscalls that accept already
> split mode and mode_flags.
>
> Signed-off-by: Gregory Price <gregory.price@xxxxxxxxxxxx>
> ---
> mm/mempolicy.c | 29 ++++++++++++++++++++++-------
> 1 file changed, 22 insertions(+), 7 deletions(-)
>
> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> index 0a180c670f0c..59ac0da24f56 100644
> --- a/mm/mempolicy.c
> +++ b/mm/mempolicy.c
> @@ -1463,24 +1463,39 @@ static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode,
> return copy_to_user(mask, nodes_addr(*nodes), copy) ? -EFAULT : 0;
> }
>
> -/* Basic parameter sanity check used by both mbind() and set_mempolicy() */
> -static inline int sanitize_mpol_flags(int *mode, unsigned short *flags)
> +/*
> + * Basic parameter sanity check used by mbind/set_mempolicy
> + * May modify flags to include internal flags (e.g. MPOL_F_MOF/F_MORON)
> + */
> +static inline int validate_mpol_flags(unsigned short mode, unsigned short *flags)
> {
> - *flags = *mode & MPOL_MODE_FLAGS;
> - *mode &= ~MPOL_MODE_FLAGS;
> -
> - if ((unsigned int)(*mode) >= MPOL_MAX)
> + if ((unsigned int)(mode) >= MPOL_MAX)
> return -EINVAL;
> if ((*flags & MPOL_F_STATIC_NODES) && (*flags & MPOL_F_RELATIVE_NODES))
> return -EINVAL;
> if (*flags & MPOL_F_NUMA_BALANCING) {
> - if (*mode != MPOL_BIND)
> + if (mode != MPOL_BIND)
> return -EINVAL;
> *flags |= (MPOL_F_MOF | MPOL_F_MORON);
> }
> return 0;
> }
>
> +/*
> + * Used by mbind/set_memplicy to split and validate mode/flags
> + * set_mempolicy combines (mode | flags), split them out into separate
mbind() uses mode flags too.
> + * fields and return just the mode in mode_arg and flags in flags.
> + */
> +static inline int sanitize_mpol_flags(int *mode_arg, unsigned short *flags)
> +{
> + unsigned short mode = (*mode_arg & ~MPOL_MODE_FLAGS);
> +
> + *flags = *mode_arg & MPOL_MODE_FLAGS;
> + *mode_arg = mode;
It appears that it's unnecessary to introduce a local variable to split
mode/flags. Just reuse the original code?
> +
> + return validate_mpol_flags(mode, flags);
> +}
> +
> static long kernel_mbind(unsigned long start, unsigned long len,
> unsigned long mode, const unsigned long __user *nmask,
> unsigned long maxnode, unsigned int flags)
--
Best Regards,
Huang, Ying
