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>
---
 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

On Tue, Sep 16, 2025 at 03:11:58PM +0100, Lorenzo Stoakes wrote:
> 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>
> ---
>  fs/resctrl/pseudo_lock.c | 20 +++++++++-----------
>  1 file changed, 9 insertions(+), 11 deletions(-)

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason

On Tue, Sep 16, 2025 at 02:40:27PM -0300, Jason Gunthorpe wrote:
> On Tue, Sep 16, 2025 at 03:11:58PM +0100, Lorenzo Stoakes wrote:
> > 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>
> > ---
> >  fs/resctrl/pseudo_lock.c | 20 +++++++++-----------
> >  1 file changed, 9 insertions(+), 11 deletions(-)
>
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Thanks for this + all other tags, very much appreciated! :)

>
> Jason

Cheers, Lorenzo