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Message-ID: <d9e9407d2ee4119c83a704a80763e5344afb42f5.1757329751.git.lorenzo.stoakes@oracle.com>
Date: Mon, 8 Sep 2025 12:10:43 +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>,
Thomas Bogendoerfer <tsbogend@...ha.franken.de>,
Heiko Carstens <hca@...ux.ibm.com>, Vasily Gorbik <gor@...ux.ibm.com>,
Alexander Gordeev <agordeev@...ux.ibm.com>,
Christian Borntraeger <borntraeger@...ux.ibm.com>,
Sven Schnelle <svens@...ux.ibm.com>,
"David S . Miller" <davem@...emloft.net>,
Andreas Larsson <andreas@...sler.com>, Arnd Bergmann <arnd@...db.de>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Dan Williams <dan.j.williams@...el.com>,
Vishal Verma <vishal.l.verma@...el.com>,
Dave Jiang <dave.jiang@...el.com>, Nicolas Pitre <nico@...xnic.net>,
Muchun Song <muchun.song@...ux.dev>,
Oscar Salvador <osalvador@...e.de>,
David Hildenbrand <david@...hat.com>,
Konstantin Komarov <almaz.alexandrovich@...agon-software.com>,
Baoquan He <bhe@...hat.com>, Vivek Goyal <vgoyal@...hat.com>,
Dave Young <dyoung@...hat.com>, Tony Luck <tony.luck@...el.com>,
Reinette Chatre <reinette.chatre@...el.com>,
Dave Martin <Dave.Martin@....com>, James Morse <james.morse@....com>,
Alexander Viro <viro@...iv.linux.org.uk>,
Christian Brauner <brauner@...nel.org>, Jan Kara <jack@...e.cz>,
"Liam R . Howlett" <Liam.Howlett@...cle.com>,
Vlastimil Babka <vbabka@...e.cz>, Mike Rapoport <rppt@...nel.org>,
Suren Baghdasaryan <surenb@...gle.com>, Michal Hocko <mhocko@...e.com>,
Hugh Dickins <hughd@...gle.com>,
Baolin Wang <baolin.wang@...ux.alibaba.com>,
Uladzislau Rezki <urezki@...il.com>,
Dmitry Vyukov <dvyukov@...gle.com>,
Andrey Konovalov <andreyknvl@...il.com>, Jann Horn <jannh@...gle.com>,
Pedro Falcato <pfalcato@...e.de>, linux-doc@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
linux-csky@...r.kernel.org, linux-mips@...r.kernel.org,
linux-s390@...r.kernel.org, sparclinux@...r.kernel.org,
nvdimm@...ts.linux.dev, linux-cxl@...r.kernel.org, linux-mm@...ck.org,
ntfs3@...ts.linux.dev, kexec@...ts.infradead.org,
kasan-dev@...glegroups.com, Jason Gunthorpe <jgg@...dia.com>
Subject: [PATCH 12/16] mm: update resctl to use mmap_prepare, mmap_complete, mmap_abort
resctl uses remap_pfn_range(), but holds a mutex over the
operation. Therefore, establish the mutex in mmap_prepare(), release it in
mmap_complete() and release it in mmap_abort() should the operation fail.
Otherwise, we simply make use of the remap_pfn_range_[prepare/complete]()
remap PFN range variants in an ordinary way.
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
---
fs/resctrl/pseudo_lock.c | 56 +++++++++++++++++++++++++++++++---------
1 file changed, 44 insertions(+), 12 deletions(-)
diff --git a/fs/resctrl/pseudo_lock.c b/fs/resctrl/pseudo_lock.c
index 87bbc2605de1..6d18ffde6a94 100644
--- a/fs/resctrl/pseudo_lock.c
+++ b/fs/resctrl/pseudo_lock.c
@@ -995,7 +995,8 @@ 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_complete(struct file *filp, struct vm_area_struct *vma,
+ const void *context)
{
unsigned long vsize = vma->vm_end - vma->vm_start;
unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
@@ -1004,6 +1005,40 @@ static int pseudo_lock_dev_mmap(struct file *filp, struct vm_area_struct *vma)
unsigned long physical;
unsigned long psize;
+ rdtgrp = filp->private_data;
+ plr = rdtgrp->plr;
+
+ physical = __pa(plr->kmem) >> PAGE_SHIFT;
+ psize = plr->size - off;
+
+ memset(plr->kmem + off, 0, vsize);
+
+ if (remap_pfn_range_complete(vma, vma->vm_start, physical + vma->vm_pgoff,
+ vsize, vma->vm_page_prot)) {
+ mutex_unlock(&rdtgroup_mutex);
+ return -EAGAIN;
+ }
+
+ mutex_unlock(&rdtgroup_mutex);
+ return 0;
+}
+
+static void pseudo_lock_dev_mmap_abort(const struct file *filp,
+ const void *vm_private_data,
+ const void *context)
+{
+ mutex_unlock(&rdtgroup_mutex);
+}
+
+static int pseudo_lock_dev_mmap_prepare(struct vm_area_desc *desc)
+{
+ unsigned long vsize = vma_desc_size(desc);
+ unsigned long off = desc->pgoff << PAGE_SHIFT;
+ struct file *filp = desc->file;
+ struct pseudo_lock_region *plr;
+ struct rdtgroup *rdtgrp;
+ unsigned long psize;
+
mutex_lock(&rdtgroup_mutex);
rdtgrp = filp->private_data;
@@ -1031,7 +1066,6 @@ static int pseudo_lock_dev_mmap(struct file *filp, struct vm_area_struct *vma)
return -EINVAL;
}
- physical = __pa(plr->kmem) >> PAGE_SHIFT;
psize = plr->size - off;
if (off > plr->size) {
@@ -1043,7 +1077,7 @@ 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;
}
@@ -1053,15 +1087,11 @@ static int pseudo_lock_dev_mmap(struct file *filp, struct vm_area_struct *vma)
return -ENOSPC;
}
- memset(plr->kmem + off, 0, vsize);
+ /* No CoW allowed so don't need to specify pfn. */
+ remap_pfn_range_prepare(desc, 0);
+ desc->vm_ops = &pseudo_mmap_ops;
- 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;
- mutex_unlock(&rdtgroup_mutex);
+ /* mutex will be release in mmap_complete or mmap_abort. */
return 0;
}
@@ -1071,7 +1101,9 @@ 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,
+ .mmap_complete = pseudo_lock_dev_mmap_complete,
+ .mmap_abort = pseudo_lock_dev_mmap_abort,
};
int rdt_pseudo_lock_init(void)
--
2.51.0
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