linux-kernel - [PATCH v2 12/16] mm: update resctl to use mmap

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Message-ID: <f0bfba7672f5fb39dffeeed65c64900d65ba0124.1757534913.git.lorenzo.stoakes@oracle.com>
Date: Wed, 10 Sep 2025 21:22:07 +0100
From: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Jonathan Corbet <corbet@....net>, Matthew Wilcox <willy@...radead.org>,
        Guo Ren <guoren@...nel.org>,
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Subject: [PATCH v2 12/16] mm: update resctl to use mmap_prepare

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@...cle.com>
---
 fs/resctrl/pseudo_lock.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/fs/resctrl/pseudo_lock.c b/fs/resctrl/pseudo_lock.c
index 87bbc2605de1..e847df586766 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 +1056,11 @@ 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(&desc->action, desc->start, physical + desc->pgoff,
+			  vsize, desc->page_prot);
+
 	mutex_unlock(&rdtgroup_mutex);
 	return 0;
 }
@@ -1071,7 +1071,7 @@ 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