[RFC PATCH 01/11] mm/mempolicy: refactor do_set_mempolicy for code re-use

Gregory Price
2023-11-22T21:12:18Z

Refactors do_set_mempolicy into replace_mempolicy and do_set_mempolicy
so that replace_mempolicy can be re-used with new code, not just
the system call.

Signed-off-by: Gregory Price <gregory.price@memverge.com>
---
mm/mempolicy.c | 36 +++++++++++++++++++++++-------------
1 file changed, 23 insertions(+), 13 deletions(-)

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 10a590ee1c89..410754d56e46 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -809,28 +809,20 @@ static int mbind_range(struct vma_iterator *vmi, struct vm_area_struct *vma,
return vma_replace_policy(vma, new_pol);
}

-/* Set the process memory policy */
-static long do_set_mempolicy(unsigned short mode, unsigned short flags,
- nodemask_t *nodes)
+/* Attempt to replace mempolicy, release the old one if successful */
+static long replace_mempolicy(struct mempolicy *new, nodemask_t *nodes)
{
- struct mempolicy *new, *old;
+ struct mempolicy *old = NULL;
NODEMASK_SCRATCH(scratch);
int ret;

if (!scratch)
return -ENOMEM;

- new = mpol_new(mode, flags, nodes);
- if (IS_ERR(new)) {
- ret = PTR_ERR(new);
- goto out;
- }
-
task_lock(current);
ret = mpol_set_nodemask(new, nodes, scratch);
if (ret) {
task_unlock(current);
- mpol_put(new);
goto out;
}

@@ -838,14 +830,32 @@ static long do_set_mempolicy(unsigned short mode, unsigned short flags,
current->mempolicy = new;
if (new && new->mode == MPOL_INTERLEAVE)
current->il_prev = MAX_NUMNODES-1;
+out:
task_unlock(current);
mpol_put(old);
- ret = 0;
-out:
+
NODEMASK_SCRATCH_FREE(scratch);
return ret;
}

+/* Set the process memory policy */
+static long do_set_mempolicy(unsigned short mode, unsigned short flags,
+ nodemask_t *nodes)
+{
+ struct mempolicy *new;
+ int ret;
+
+ new = mpol_new(mode, flags, nodes);
+ if (IS_ERR(new))
+ return PTR_ERR(new);
+
+ ret = replace_mempolicy(new, nodes);
+ if (ret)
+ mpol_put(new);
+
+ return ret;
+}
+
/*
* Return nodemask for policy for get_mempolicy() query
*
--
2.39.1