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Message-Id: <20061026133305.b0db54e6.sfr@canb.auug.org.au>
Date: Thu, 26 Oct 2006 13:33:05 +1000
From: Stephen Rothwell <sfr@...b.auug.org.au>
To: LKML <linux-kernel@...r.kernel.org>
Cc: ppc-dev <linuxppc-dev@...abs.org>, paulus@...ba.org, ak@...e.de,
linux-mm@...ck.org
Subject: [PATCH 2/3] Create compat_sys_migrate_pages
This is needed on bigendian 64bit architectures. The obvious way to do
this (taking the other compat_ routines in this file as examples) is to
use compat_alloc_user_space and copy the bitmasks back there, however you
cannot call compat_alloc_user_space twice for a single system call and
this method saves two copies of the bitmasks.
Signed-off-by: Stephen Rothwell <sfr@...b.auug.org.au>
---
mm/mempolicy.c | 107 ++++++++++++++++++++++++++++++++++++++++++++++++-------
1 files changed, 93 insertions(+), 14 deletions(-)
Maybe the other compat routines in here should be converted to use
compat_get_nodes as well.
--
Cheers,
Stephen Rothwell sfr@...b.auug.org.au
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 617fb31..65c0281 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -854,6 +854,58 @@ static int get_nodes(nodemask_t *nodes,
return 0;
}
+#ifdef CONFIG_COMPAT
+static int compat_get_nodes(nodemask_t *nodes,
+ const compat_ulong_t __user *nmask, unsigned long maxnode)
+{
+ unsigned long k;
+ unsigned long nlongs;
+ unsigned long nbits = maxnode - 1;
+ compat_ulong_t endmask;
+
+ if (maxnode == 0)
+ return -EINVAL;
+ nodes_clear(*nodes);
+ if (nbits == 0 || !nmask)
+ return 0;
+ if (nbits > PAGE_SIZE * BITS_PER_BYTE)
+ return -EINVAL;
+
+ nlongs = BITS_TO_COMPAT_LONGS(nbits);
+ if ((nbits % BITS_PER_COMPAT_LONG) == 0)
+ endmask = (compat_ulong_t)~0;
+ else
+ endmask = ((compat_ulong_t)1 <<
+ (nbits % BITS_PER_COMPAT_LONG)) - 1;
+
+ /* When the user specified more nodes than supported just check
+ if the non supported part is all zero. */
+ if (nbits > MAX_NUMNODES) {
+ if (nlongs > PAGE_SIZE / sizeof(compat_ulong_t))
+ return -EINVAL;
+ for (k = BITS_TO_COMPAT_LONGS(MAX_NUMNODES); k < nlongs; k++) {
+ compat_ulong_t t;
+
+ if (get_user(t, nmask + k))
+ return -EFAULT;
+ if (k == (nlongs - 1)) {
+ if (t & endmask)
+ return -EINVAL;
+ } else if (t)
+ return -EINVAL;
+ }
+ nbits = MAX_NUMNODES;
+ endmask = ~0;
+ }
+
+ if (compat_get_bitmap(nodes_addr(*nodes), nmask, nbits))
+ return -EFAULT;
+ if (nbits % BITS_PER_COMPAT_LONG)
+ nodes_addr(*nodes)[BITS_TO_COMPAT_LONGS(nbits) - 1] &= endmask;
+ return 0;
+}
+#endif /* CONFIG_COMPAT */
+
/* Copy a kernel node mask to user space */
static int copy_nodes_to_user(unsigned long __user *mask, unsigned long maxnode,
nodemask_t *nodes)
@@ -900,25 +952,13 @@ asmlinkage long sys_set_mempolicy(int mo
return do_set_mempolicy(mode, &nodes);
}
-asmlinkage long sys_migrate_pages(pid_t pid, unsigned long maxnode,
- const unsigned long __user *old_nodes,
- const unsigned long __user *new_nodes)
+static long internal_migrate_pages(pid_t pid, nodemask_t *old, nodemask_t *new)
{
struct mm_struct *mm;
struct task_struct *task;
- nodemask_t old;
- nodemask_t new;
nodemask_t task_nodes;
int err;
- err = get_nodes(&old, old_nodes, maxnode);
- if (err)
- return err;
-
- err = get_nodes(&new, new_nodes, maxnode);
- if (err)
- return err;
-
/* Find the mm_struct */
read_lock(&tasklist_lock);
task = pid ? find_task_by_pid(pid) : current;
@@ -963,6 +1003,25 @@ out:
return err;
}
+asmlinkage long sys_migrate_pages(pid_t pid, unsigned long maxnode,
+ const unsigned long __user *old_nodes,
+ const unsigned long __user *new_nodes)
+{
+ nodemask_t old;
+ nodemask_t new;
+ int err;
+
+ err = get_nodes(&old, old_nodes, maxnode);
+ if (err)
+ return err;
+
+ err = get_nodes(&new, new_nodes, maxnode);
+ if (err)
+ return err;
+
+ return internal_migrate_pages(pid, old, new);
+}
+
/* Retrieve NUMA policy */
asmlinkage long sys_get_mempolicy(int __user *policy,
@@ -1067,7 +1126,27 @@ asmlinkage long compat_sys_mbind(compat_
return sys_mbind(start, len, mode, nm, nr_bits+1, flags);
}
-#endif
+asmlinkage long compat_sys_migrate_pages(compat_pid_t pid,
+ compat_ulong_t maxnode,
+ const compat_ulong_t __user *old_nodes,
+ const compat_ulong_t __user *new_nodes)
+{
+ nodemask_t old;
+ nodemask_t new;
+ int err;
+
+ err = get_nodes(&old, old_nodes, maxnode);
+ if (err)
+ return err;
+
+ err = get_nodes(&new, new_nodes, maxnode);
+ if (err)
+ return err;
+
+ return internal_migrate_pages(pid, old, new);
+}
+
+#endif /* CONFIG_COMPAT */
/* Return effective policy for a VMA */
static struct mempolicy * get_vma_policy(struct task_struct *task,
--
1.4.3.2
-
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