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