On Mon, May 24, 2021 at 01:59:39PM +0800, Tang, Feng wrote:
> On Sun, May 23, 2021 at 10:16:11PM -0700, David Rientjes wrote:
> > On Thu, 20 May 2021, Feng Tang wrote:
> >
> > > Currently the kernel_mbind() and kernel_set_mempolicy() do almost
> > > the same operation for parameter sanity check and preprocessing.
> > >
> > > Add a macro to unify the code to reduce the redundancy, and make
> > > it easier for changing the pre-processing code in future.
> > >
> > > Signed-off-by: Feng Tang <feng.tang@xxxxxxxxx>
> > > ---
> > > mm/mempolicy.c | 46 +++++++++++++++++++---------------------------
> > > 1 file changed, 19 insertions(+), 27 deletions(-)
> > >
> > > diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> > > index 1964cca..0f5bf60 100644
> > > --- a/mm/mempolicy.c
> > > +++ b/mm/mempolicy.c
> > > @@ -1460,25 +1460,29 @@ static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode,
> > > return copy_to_user(mask, nodes_addr(*nodes), copy) ? -EFAULT : 0;
> > > }
> > >
> > > +#define MPOL_PRE_PROCESS() \
> >
> > This should be extracted to helper function returning bool, not a macro.
>
> Yes, initially I did try it with an inline function, but as a function
> it has quite several input parameters and several output parameters,
> which made the code still big and ugly.
>
> But if community think it's the right direction to go, I can change it.
Following is a patch to unify the preprocssing by using a helper function,
please review, thanks
- Feng
---
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index d79fa299b70c..8e4f47f925b6 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1460,6 +1460,20 @@ 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 mpol_pre_process(int *mode, const unsigned long __user *nmask, unsigned long maxnode, nodemask_t *nodes, unsigned short *flags)
+{
+ int ret;
+
+ *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;
+ ret = get_nodes(nodes, nmask, maxnode);
+ return ret;
+}
+
static long kernel_mbind(unsigned long start, unsigned long len,
unsigned long mode, const unsigned long __user *nmask,
unsigned long maxnode, unsigned int flags)
@@ -1467,19 +1481,14 @@ static long kernel_mbind(unsigned long start, unsigned long len,
nodemask_t nodes;
int err;
unsigned short mode_flags;
+ int lmode = mode;
- 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 = get_nodes(&nodes, nmask, maxnode);
+ err = mpol_pre_process(&lmode, nmask, maxnode, &nodes, &mode_flags);
if (err)
return err;
- return do_mbind(start, len, mode, mode_flags, &nodes, flags);
+
+ start = untagged_addr(start);
+ return do_mbind(start, len, lmode, mode_flags, &nodes, flags);
}
SYSCALL_DEFINE6(mbind, unsigned long, start, unsigned long, len,
@@ -1495,18 +1504,14 @@ static long kernel_set_mempolicy(int mode, const unsigned long __user *nmask,
{
int err;
nodemask_t nodes;
- unsigned short flags;
+ unsigned short mode_flags;
+ int lmode = mode;
- 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);
+ err = mpol_pre_process(&lmode, nmask, maxnode, &nodes, &mode_flags);
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,
