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Date: Mon, 9 Jan 2023 11:45:17 +0500
From: Muhammad Usama Anjum <usama.anjum@...labora.com>
To: Peter Xu <peterx@...hat.com>, David Hildenbrand <david@...hat.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Michał Mirosław <emmir@...gle.com>,
Andrei Vagin <avagin@...il.com>,
Danylo Mocherniuk <mdanylo@...gle.com>,
Paul Gofman <pgofman@...eweavers.com>,
Cyrill Gorcunov <gorcunov@...il.com>
Cc: Alexander Viro <viro@...iv.linux.org.uk>,
Shuah Khan <shuah@...nel.org>,
Christian Brauner <brauner@...nel.org>,
Yang Shi <shy828301@...il.com>,
Vlastimil Babka <vbabka@...e.cz>,
"Liam R . Howlett" <Liam.Howlett@...cle.com>,
Yun Zhou <yun.zhou@...driver.com>,
Suren Baghdasaryan <surenb@...gle.com>,
Alex Sierra <alex.sierra@....com>,
Muhammad Usama Anjum <usama.anjum@...labora.com>,
Matthew Wilcox <willy@...radead.org>,
Pasha Tatashin <pasha.tatashin@...een.com>,
Mike Rapoport <rppt@...nel.org>, Nadav Amit <namit@...are.com>,
Axel Rasmussen <axelrasmussen@...gle.com>,
"Gustavo A . R . Silva" <gustavoars@...nel.org>,
Dan Williams <dan.j.williams@...el.com>,
linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
linux-mm@...ck.org, linux-kselftest@...r.kernel.org,
Greg KH <gregkh@...uxfoundation.org>, kernel@...labora.com
Subject: [PATCH v7 2/4] userfaultfd: split mwriteprotect_range()
Split mwriteprotect_range() to create a unlocked version. This
will be used in the next patch to write protect a memory area.
Add a helper function, wp_range_async() as well.
Signed-off-by: Muhammad Usama Anjum <usama.anjum@...labora.com>
---
fs/userfaultfd.c | 11 ++++++++++
include/linux/userfaultfd_k.h | 10 +++++++++
mm/userfaultfd.c | 40 ++++++++++++++++++++++-------------
3 files changed, 46 insertions(+), 15 deletions(-)
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index be5e10d15058..5ff5ff4314e3 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -1967,6 +1967,17 @@ static int userfaultfd_continue(struct userfaultfd_ctx *ctx, unsigned long arg)
return ret;
}
+int wp_range_async(struct vm_area_struct *vma, unsigned long start, unsigned long len)
+{
+ struct userfaultfd_ctx *ctx = vma->vm_userfaultfd_ctx.ctx;
+
+ if (!ctx)
+ return -1;
+
+ ctx->async = true;
+ return __mwriteprotect_range(ctx->mm, start, len, true, &ctx->mmap_changing);
+}
+
static inline unsigned int uffd_ctx_features(__u64 user_features)
{
/*
diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h
index 9df0b9a762cc..fba05a32f8e9 100644
--- a/include/linux/userfaultfd_k.h
+++ b/include/linux/userfaultfd_k.h
@@ -73,6 +73,9 @@ extern ssize_t mcopy_continue(struct mm_struct *dst_mm, unsigned long dst_start,
extern int mwriteprotect_range(struct mm_struct *dst_mm,
unsigned long start, unsigned long len,
bool enable_wp, atomic_t *mmap_changing);
+extern int __mwriteprotect_range(struct mm_struct *dst_mm,
+ unsigned long start, unsigned long len,
+ bool enable_wp, atomic_t *mmap_changing);
extern void uffd_wp_range(struct mm_struct *dst_mm, struct vm_area_struct *vma,
unsigned long start, unsigned long len, bool enable_wp);
@@ -179,6 +182,8 @@ extern int userfaultfd_unmap_prep(struct mm_struct *mm, unsigned long start,
unsigned long end, struct list_head *uf);
extern void userfaultfd_unmap_complete(struct mm_struct *mm,
struct list_head *uf);
+extern int wp_range_async(struct vm_area_struct *vma, unsigned long start,
+ unsigned long len);
#else /* CONFIG_USERFAULTFD */
@@ -274,6 +279,11 @@ static inline bool uffd_disable_fault_around(struct vm_area_struct *vma)
return false;
}
+int wp_range_async(struct vm_area_struct *vma, unsigned long start, unsigned long len)
+{
+ return -1;
+}
+
#endif /* CONFIG_USERFAULTFD */
static inline bool pte_marker_entry_uffd_wp(swp_entry_t entry)
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index 65ad172add27..9d8a43faf764 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -734,25 +734,13 @@ void uffd_wp_range(struct mm_struct *dst_mm, struct vm_area_struct *dst_vma,
tlb_finish_mmu(&tlb);
}
-int mwriteprotect_range(struct mm_struct *dst_mm, unsigned long start,
- unsigned long len, bool enable_wp,
- atomic_t *mmap_changing)
+int __mwriteprotect_range(struct mm_struct *dst_mm, unsigned long start,
+ unsigned long len, bool enable_wp,
+ atomic_t *mmap_changing)
{
struct vm_area_struct *dst_vma;
unsigned long page_mask;
int err;
-
- /*
- * Sanitize the command parameters:
- */
- BUG_ON(start & ~PAGE_MASK);
- BUG_ON(len & ~PAGE_MASK);
-
- /* Does the address range wrap, or is the span zero-sized? */
- BUG_ON(start + len <= start);
-
- mmap_read_lock(dst_mm);
-
/*
* If memory mappings are changing because of non-cooperative
* operation (e.g. mremap) running in parallel, bail out and
@@ -783,6 +771,28 @@ int mwriteprotect_range(struct mm_struct *dst_mm, unsigned long start,
err = 0;
out_unlock:
+ return err;
+}
+
+int mwriteprotect_range(struct mm_struct *dst_mm, unsigned long start,
+ unsigned long len, bool enable_wp,
+ atomic_t *mmap_changing)
+{
+ int err;
+
+ /*
+ * Sanitize the command parameters:
+ */
+ BUG_ON(start & ~PAGE_MASK);
+ BUG_ON(len & ~PAGE_MASK);
+
+ /* Does the address range wrap, or is the span zero-sized? */
+ BUG_ON(start + len <= start);
+
+ mmap_read_lock(dst_mm);
+
+ err = __mwriteprotect_range(dst_mm, start, len, enable_wp, mmap_changing);
+
mmap_read_unlock(dst_mm);
return err;
}
--
2.30.2
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