diff mbox series

[RFC,v2,2/4] mm/mempolicy: unify the preprocessing for mbind and set_mempolicy

Message ID 1621499404-67756-3-git-send-email-feng.tang@intel.com (mailing list archive)
State New, archived
Headers show
Series mm/mempolicy: some fix and semantics cleanup | expand

Commit Message

Feng Tang May 20, 2021, 8:30 a.m. UTC 
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@intel.com>
---
 mm/mempolicy.c | 46 +++++++++++++++++++---------------------------
 1 file changed, 19 insertions(+), 27 deletions(-)

Comments

David Rientjes May 24, 2021, 5:16 a.m. UTC | #1 
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@intel.com>
> ---
>  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.

> +	 \
> +	nodemask_t nodes; \
> +	int err; \
> +	unsigned short mode_flags; \
> +	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); \
> +	if (err) \
> +		return err;
> +
>  static long kernel_mbind(unsigned long start, unsigned long len,
>  			 unsigned long mode, const unsigned long __user *nmask,
>  			 unsigned long maxnode, unsigned int flags)
>  {
> -	nodemask_t nodes;
> -	int err;
> -	unsigned short mode_flags;
> +	MPOL_PRE_PROCESS();
>  
>  	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);
> -	if (err)
> -		return err;
>  	return do_mbind(start, len, mode, mode_flags, &nodes, flags);
>  }
>  
> @@ -1493,20 +1497,8 @@ 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;
> -	nodemask_t nodes;
> -	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;
> -	err = get_nodes(&nodes, nmask, maxnode);
> -	if (err)
> -		return err;
> -	return do_set_mempolicy(mode, flags, &nodes);
> +	MPOL_PRE_PROCESS();
> +	return do_set_mempolicy(mode, mode_flags, &nodes);
>  }
>  
>  SYSCALL_DEFINE3(set_mempolicy, int, mode, const unsigned long __user *, nmask,
> -- 
> 2.7.4
> 
>
Feng Tang May 24, 2021, 5:59 a.m. UTC | #2 
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@intel.com>
> > ---
> >  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.

Thanks,
Feng

> > +	 \
> > +	nodemask_t nodes; \
> > +	int err; \
> > +	unsigned short mode_flags; \
> > +	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); \
> > +	if (err) \
> > +		return err;
> > +
> >  static long kernel_mbind(unsigned long start, unsigned long len,
> >  			 unsigned long mode, const unsigned long __user *nmask,
> >  			 unsigned long maxnode, unsigned int flags)
> >  {
> > -	nodemask_t nodes;
> > -	int err;
> > -	unsigned short mode_flags;
> > +	MPOL_PRE_PROCESS();
> >  
> >  	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);
> > -	if (err)
> > -		return err;
> >  	return do_mbind(start, len, mode, mode_flags, &nodes, flags);
> >  }
> >  
> > @@ -1493,20 +1497,8 @@ 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;
> > -	nodemask_t nodes;
> > -	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;
> > -	err = get_nodes(&nodes, nmask, maxnode);
> > -	if (err)
> > -		return err;
> > -	return do_set_mempolicy(mode, flags, &nodes);
> > +	MPOL_PRE_PROCESS();
> > +	return do_set_mempolicy(mode, mode_flags, &nodes);
> >  }
> >  
> >  SYSCALL_DEFINE3(set_mempolicy, int, mode, const unsigned long __user *, nmask,
> > -- 
> > 2.7.4
> > 
> >
Feng Tang May 24, 2021, 8:32 a.m. UTC | #3 
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@intel.com>
> > > ---
> > >  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,
diff mbox series

Patch

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() \
+	 \
+	nodemask_t nodes; \
+	int err; \
+	unsigned short mode_flags; \
+	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); \
+	if (err) \
+		return err;
+
 static long kernel_mbind(unsigned long start, unsigned long len,
 			 unsigned long mode, const unsigned long __user *nmask,
 			 unsigned long maxnode, unsigned int flags)
 {
-	nodemask_t nodes;
-	int err;
-	unsigned short mode_flags;
+	MPOL_PRE_PROCESS();
 
 	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);
-	if (err)
-		return err;
 	return do_mbind(start, len, mode, mode_flags, &nodes, flags);
 }
 
@@ -1493,20 +1497,8 @@  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;
-	nodemask_t nodes;
-	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;
-	err = get_nodes(&nodes, nmask, maxnode);
-	if (err)
-		return err;
-	return do_set_mempolicy(mode, flags, &nodes);
+	MPOL_PRE_PROCESS();
+	return do_set_mempolicy(mode, mode_flags, &nodes);
 }
 
 SYSCALL_DEFINE3(set_mempolicy, int, mode, const unsigned long __user *, nmask,