Message ID | 1622469956-82897-4-git-send-email-feng.tang@intel.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | mm/mempolicy: some fix and semantics cleanup | expand |
On Mon 31-05-21 22:05:56, Feng Tang wrote: > Currently the kernel_mbind() and kernel_set_mempolicy() do almost > the same operation for parameter sanity check. > > Add a helper function to unify the code to reduce the redundancy, > and make it easier for changing the pre-processing code in future. > > [thanks to David Rientjes for suggesting using helper function > instead of macro] > > Signed-off-by: Feng Tang <feng.tang@intel.com> sanitize_mpol_flags would benefit from some high level comments explaining those modifications but this can be done on top. This looks like a useful cleanup on its own Acked-by: Michal Hocko <mhocko@suse.com> Thanks! > --- > mm/mempolicy.c | 47 +++++++++++++++++++++++++++++------------------ > 1 file changed, 29 insertions(+), 18 deletions(-) > > diff --git a/mm/mempolicy.c b/mm/mempolicy.c > index c337bd7..85ef512 100644 > --- a/mm/mempolicy.c > +++ b/mm/mempolicy.c > @@ -1444,26 +1444,37 @@ static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode, > return copy_to_user(mask, nodes_addr(*nodes), copy) ? -EFAULT : 0; > } > > +static inline int sanitize_mpol_flags(int *mode, unsigned short *flags) > +{ > + *flags = *mode & MPOL_MODE_FLAGS; > + *mode &= ~MPOL_MODE_FLAGS; > + if ((unsigned int)(*mode) >= MPOL_MAX) > + return -EINVAL; > + if ((*flags & MPOL_F_STATIC_NODES) && (*flags & MPOL_F_RELATIVE_NODES)) > + return -EINVAL; > + > + return 0; > +} > + > static long kernel_mbind(unsigned long start, unsigned long len, > unsigned long mode, const unsigned long __user *nmask, > unsigned long maxnode, unsigned int flags) > { > + unsigned short mode_flags; > nodemask_t nodes; > + int lmode = mode; > int err; > - unsigned short mode_flags; > > start = untagged_addr(start); > - mode_flags = mode & MPOL_MODE_FLAGS; > - mode &= ~MPOL_MODE_FLAGS; > - if (mode >= MPOL_MAX) > - return -EINVAL; > - if ((mode_flags & MPOL_F_STATIC_NODES) && > - (mode_flags & MPOL_F_RELATIVE_NODES)) > - return -EINVAL; > + err = sanitize_mpol_flags(&lmode, &mode_flags); > + if (err) > + return err; > + > err = get_nodes(&nodes, nmask, maxnode); > if (err) > return err; > - return do_mbind(start, len, mode, mode_flags, &nodes, flags); > + > + return do_mbind(start, len, lmode, mode_flags, &nodes, flags); > } > > SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len, > @@ -1477,20 +1488,20 @@ SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len, > static long kernel_set_mempolicy(int mode, const unsigned long __user *nmask, > unsigned long maxnode) > { > - int err; > + unsigned short mode_flags; > nodemask_t nodes; > - unsigned short flags; > + int lmode = mode; > + int err; > + > + err = sanitize_mpol_flags(&lmode, &mode_flags); > + if (err) > + return err; > > - flags = mode & MPOL_MODE_FLAGS; > - mode &= ~MPOL_MODE_FLAGS; > - if ((unsigned int)mode >= MPOL_MAX) > - return -EINVAL; > - if ((flags & MPOL_F_STATIC_NODES) && (flags & MPOL_F_RELATIVE_NODES)) > - return -EINVAL; > err = get_nodes(&nodes, nmask, maxnode); > if (err) > return err; > - return do_set_mempolicy(mode, flags, &nodes); > + > + return do_set_mempolicy(lmode, mode_flags, &nodes); > } > > SYSCALL_DEFINE3(set_mempolicy, int, mode, const unsigned long __user *, nmask, > -- > 2.7.4
diff --git a/mm/mempolicy.c b/mm/mempolicy.c index c337bd7..85ef512 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1444,26 +1444,37 @@ static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode, return copy_to_user(mask, nodes_addr(*nodes), copy) ? -EFAULT : 0; } +static inline int sanitize_mpol_flags(int *mode, unsigned short *flags) +{ + *flags = *mode & MPOL_MODE_FLAGS; + *mode &= ~MPOL_MODE_FLAGS; + if ((unsigned int)(*mode) >= MPOL_MAX) + return -EINVAL; + if ((*flags & MPOL_F_STATIC_NODES) && (*flags & MPOL_F_RELATIVE_NODES)) + return -EINVAL; + + return 0; +} + static long kernel_mbind(unsigned long start, unsigned long len, unsigned long mode, const unsigned long __user *nmask, unsigned long maxnode, unsigned int flags) { + unsigned short mode_flags; nodemask_t nodes; + int lmode = mode; int err; - unsigned short mode_flags; start = untagged_addr(start); - mode_flags = mode & MPOL_MODE_FLAGS; - mode &= ~MPOL_MODE_FLAGS; - if (mode >= MPOL_MAX) - return -EINVAL; - if ((mode_flags & MPOL_F_STATIC_NODES) && - (mode_flags & MPOL_F_RELATIVE_NODES)) - return -EINVAL; + err = sanitize_mpol_flags(&lmode, &mode_flags); + if (err) + return err; + err = get_nodes(&nodes, nmask, maxnode); if (err) return err; - return do_mbind(start, len, mode, mode_flags, &nodes, flags); + + return do_mbind(start, len, lmode, mode_flags, &nodes, flags); } SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len, @@ -1477,20 +1488,20 @@ SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len, static long kernel_set_mempolicy(int mode, const unsigned long __user *nmask, unsigned long maxnode) { - int err; + unsigned short mode_flags; nodemask_t nodes; - unsigned short flags; + int lmode = mode; + int err; + + err = sanitize_mpol_flags(&lmode, &mode_flags); + if (err) + return err; - flags = mode & MPOL_MODE_FLAGS; - mode &= ~MPOL_MODE_FLAGS; - if ((unsigned int)mode >= MPOL_MAX) - return -EINVAL; - if ((flags & MPOL_F_STATIC_NODES) && (flags & MPOL_F_RELATIVE_NODES)) - return -EINVAL; err = get_nodes(&nodes, nmask, maxnode); if (err) return err; - return do_set_mempolicy(mode, flags, &nodes); + + return do_set_mempolicy(lmode, mode_flags, &nodes); } SYSCALL_DEFINE3(set_mempolicy, int, mode, const unsigned long __user *, nmask,
Currently the kernel_mbind() and kernel_set_mempolicy() do almost the same operation for parameter sanity check. Add a helper function to unify the code to reduce the redundancy, and make it easier for changing the pre-processing code in future. [thanks to David Rientjes for suggesting using helper function instead of macro] Signed-off-by: Feng Tang <feng.tang@intel.com> --- mm/mempolicy.c | 47 +++++++++++++++++++++++++++++------------------ 1 file changed, 29 insertions(+), 18 deletions(-)