[PATCH v4 14/14] mm: update resctl to use mmap_prepare

Lorenzo Stoakes
2025-09-17T19:12:23Z

Make use of the ability to specify a remap action within mmap_prepare to
update the resctl pseudo-lock to use mmap_prepare in favour of the
deprecated mmap hook.

Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: Reinette Chatre <reinette.chatre@intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
---
fs/resctrl/pseudo_lock.c | 20 +++++++++-----------
1 file changed, 9 insertions(+), 11 deletions(-)

diff --git a/fs/resctrl/pseudo_lock.c b/fs/resctrl/pseudo_lock.c
index 87bbc2605de1..0bfc13c5b96d 100644
--- a/fs/resctrl/pseudo_lock.c
+++ b/fs/resctrl/pseudo_lock.c
@@ -995,10 +995,11 @@ static const struct vm_operations_struct pseudo_mmap_ops = {
.mremap = pseudo_lock_dev_mremap,
};

-static int pseudo_lock_dev_mmap(struct file *filp, struct vm_area_struct *vma)
+static int pseudo_lock_dev_mmap_prepare(struct vm_area_desc *desc)
{
- unsigned long vsize = vma->vm_end - vma->vm_start;
- unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
+ unsigned long off = desc->pgoff << PAGE_SHIFT;
+ unsigned long vsize = vma_desc_size(desc);
+ struct file *filp = desc->file;
struct pseudo_lock_region *plr;
struct rdtgroup *rdtgrp;
unsigned long physical;
@@ -1043,7 +1044,7 @@ static int pseudo_lock_dev_mmap(struct file *filp, struct vm_area_struct *vma)
* Ensure changes are carried directly to the memory being mapped,
* do not allow copy-on-write mapping.
*/
- if (!(vma->vm_flags & VM_SHARED)) {
+ if (!(desc->vm_flags & VM_SHARED)) {
mutex_unlock(&rdtgroup_mutex);
return -EINVAL;
}
@@ -1055,12 +1056,9 @@ static int pseudo_lock_dev_mmap(struct file *filp, struct vm_area_struct *vma)

memset(plr->kmem + off, 0, vsize);

- if (remap_pfn_range(vma, vma->vm_start, physical + vma->vm_pgoff,
- vsize, vma->vm_page_prot)) {
- mutex_unlock(&rdtgroup_mutex);
- return -EAGAIN;
- }
- vma->vm_ops = &pseudo_mmap_ops;
+ desc->vm_ops = &pseudo_mmap_ops;
+ mmap_action_remap_full(desc, physical + desc->pgoff);
+
mutex_unlock(&rdtgroup_mutex);
return 0;
}
@@ -1071,7 +1069,7 @@ static const struct file_operations pseudo_lock_dev_fops = {
.write = NULL,
.open = pseudo_lock_dev_open,
.release = pseudo_lock_dev_release,
- .mmap = pseudo_lock_dev_mmap,
+ .mmap_prepare = pseudo_lock_dev_mmap_prepare,
};

int rdt_pseudo_lock_init(void)
--
2.51.0