From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	patches@lists.linux.dev,
	"Mike Rapoport (Microsoft)" <rppt@kernel.org>,
	"David Hildenbrand (Red Hat)" <david@kernel.org>,
	"Liam R. Howlett" <Liam.Howlett@oracle.com>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Andrei Vagin <avagin@google.com>,
	Axel Rasmussen <axelrasmussen@google.com>,
	Baolin Wang <baolin.wang@linux.alibaba.com>,
	Harry Yoo <harry.yoo@oracle.com>,
	"Harry Yoo (Oracle)" <harry@kernel.org>,
	Hugh Dickins <hughd@google.com>,
	James Houghton <jthoughton@google.com>,
	"Lorenzo Stoakes (Oracle)" <ljs@kernel.org>,
	"Matthew Wilcox (Oracle)" <willy@infradead.org>,
	Michal Hocko <mhocko@suse.com>,
	Muchun Song <muchun.song@linux.dev>,
	Nikita Kalyazin <kalyazin@amazon.com>,
	Oscar Salvador <osalvador@suse.de>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Peter Xu <peterx@redhat.com>,
	Sean Christopherson <seanjc@google.com>,
	Shuah Khan <shuah@kernel.org>,
	Suren Baghdasaryan <surenb@google.com>,
	Vlastimil Babka <vbabka@suse.cz>,
	David Carlier <devnexen@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 6.6 080/166] userfaultfd: move vma_can_userfault out of line
Date: Thu, 20 Aug 2026 16:55:39 +0200
Message-ID: <20260820145213.556469572@linuxfoundation.org>
In-Reply-To: <20260820145211.194104353@linuxfoundation.org>
References: <20260820145211.194104353@linuxfoundation.org>
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6.6-stable review patch.  If anyone has any objections, please let me know.

------------------

From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>

[ Upstream commit a5bb8669872b6b8463b8777a7a259a8305060016 ]

vma_can_userfault() has grown pretty big and it's not called on
performance critical path.

Move it out of line.

No functional changes.

Link: https://lore.kernel.org/20260402041156.1377214-7-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: David Hildenbrand (Red Hat) <david@kernel.org>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrei Vagin <avagin@google.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Harry Yoo <harry.yoo@oracle.com>
Cc: Harry Yoo (Oracle) <harry@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: James Houghton <jthoughton@google.com>
Cc: Lorenzo Stoakes (Oracle) <ljs@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Nikita Kalyazin <kalyazin@amazon.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: David Carlier <devnexen@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: 3c58f641e813 ("userfaultfd: prevent registration of special VMAs")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/linux/userfaultfd_k.h |   21 +--------------------
 mm/userfaultfd.c              |   20 ++++++++++++++++++++
 2 files changed, 21 insertions(+), 20 deletions(-)

--- a/include/linux/userfaultfd_k.h
+++ b/include/linux/userfaultfd_k.h
@@ -160,26 +160,7 @@ static inline bool userfaultfd_armed(str
 	return vma->vm_flags & __VM_UFFD_FLAGS;
 }
 
-static inline bool vma_can_userfault(struct vm_area_struct *vma,
-				     unsigned long vm_flags)
-{
-	if ((vm_flags & VM_UFFD_MINOR) &&
-	    (!is_vm_hugetlb_page(vma) && !vma_is_shmem(vma)))
-		return false;
-
-	/*
-	 * If user requested uffd-wp but not enabled pte markers for
-	 * uffd-wp, then shmem & hugetlbfs are not supported but only
-	 * anonymous.
-	 */
-	if (!uffd_supports_wp_marker() && (vm_flags & VM_UFFD_WP) &&
-	    !vma_is_anonymous(vma))
-		return false;
-
-	/* By default, allow any of anon|shmem|hugetlb */
-	return vma_is_anonymous(vma) || is_vm_hugetlb_page(vma) ||
-	    vma_is_shmem(vma);
-}
+bool vma_can_userfault(struct vm_area_struct *vma, unsigned long vm_flags);
 
 extern int dup_userfaultfd(struct vm_area_struct *, struct list_head *);
 extern void dup_userfaultfd_complete(struct list_head *);
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -891,3 +891,23 @@ out_unlock:
 	mmap_read_unlock(dst_mm);
 	return err;
 }
+
+bool vma_can_userfault(struct vm_area_struct *vma, unsigned long vm_flags)
+{
+	if ((vm_flags & VM_UFFD_MINOR) &&
+	    (!is_vm_hugetlb_page(vma) && !vma_is_shmem(vma)))
+		return false;
+
+	/*
+	 * If user requested uffd-wp but not enabled pte markers for
+	 * uffd-wp, then shmem & hugetlbfs are not supported but only
+	 * anonymous.
+	 */
+	if (!uffd_supports_wp_marker() && (vm_flags & VM_UFFD_WP) &&
+	    !vma_is_anonymous(vma))
+		return false;
+
+	/* By default, allow any of anon|shmem|hugetlb */
+	return vma_is_anonymous(vma) || is_vm_hugetlb_page(vma) ||
+	    vma_is_shmem(vma);
+}