mm: move anon_vma declarations to linux/mm_inline.h

The patch to add anonymous vma names causes a build failure in some
configurations:

  include/linux/mm_types.h: In function 'is_same_vma_anon_name':
  include/linux/mm_types.h:924:37: error: implicit declaration of function 'strcmp' [-Werror=implicit-function-declaration]
    924 |         return name && vma_name && !strcmp(name, vma_name);
        |                                     ^~~~~~
  include/linux/mm_types.h:22:1: note: 'strcmp' is defined in header '<string.h>'; did you forget to '#include <string.h>'?

This should not really be part of linux/mm_types.h in the first place,
as that header is meant to only contain structure defintions and need a
minimum set of indirect includes itself.

While the header clearly includes more than it should at this point,
let's not make it worse by including string.h as well, which would pull
in the expensive (compile-speed wise) fortify-string logic.

Move the new functions into a separate header that only needs to be
included in a couple of locations.

Link: https://lkml.kernel.org/r/20211207125710.2503446-1-arnd@kernel.org
Fixes: "mm: add a field to store names for private anonymous memory"
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Colin Cross <ccross@google.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

7 files changed, 55 insertions, 48 deletions

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index e6998652fd67..18f8c3acbb85 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <linux/pagewalk.h>
 #include <linux/vmacache.h>
+#include <linux/mm_inline.h>
 #include <linux/hugetlb.h>
 #include <linux/huge_mm.h>
 #include <linux/mount.h>
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 5b2af7b82776..e26b10132d47 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -15,6 +15,7 @@
 #include <linux/sched/signal.h>
 #include <linux/sched/mm.h>
 #include <linux/mm.h>
+#include <linux/mm_inline.h>
 #include <linux/mmu_notifier.h>
 #include <linux/poll.h>
 #include <linux/slab.h>
diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h
index e2ec68b0515c..47d96d2647ca 100644
--- a/include/linux/mm_inline.h
+++ b/include/linux/mm_inline.h
@@ -4,6 +4,7 @@
 
 #include <linux/huge_mm.h>
 #include <linux/swap.h>
+#include <linux/string.h>
 
 /**
  * folio_is_file_lru - Should the folio be on a file LRU or anon LRU?
@@ -135,4 +136,53 @@ static __always_inline void del_page_from_lru_list(struct page *page,
 {
 	lruvec_del_folio(lruvec, page_folio(page));
 }
+
+#ifdef CONFIG_ANON_VMA_NAME
+/*
+ * mmap_lock should be read-locked when calling vma_anon_name() and while using
+ * the returned pointer.
+ */
+extern const char *vma_anon_name(struct vm_area_struct *vma);
+
+/*
+ * mmap_lock should be read-locked for orig_vma->vm_mm.
+ * mmap_lock should be write-locked for new_vma->vm_mm or new_vma should be
+ * isolated.
+ */
+extern void dup_vma_anon_name(struct vm_area_struct *orig_vma,
+			      struct vm_area_struct *new_vma);
+
+/*
+ * mmap_lock should be write-locked or vma should have been isolated under
+ * write-locked mmap_lock protection.
+ */
+extern void free_vma_anon_name(struct vm_area_struct *vma);
+
+/* mmap_lock should be read-locked */
+static inline bool is_same_vma_anon_name(struct vm_area_struct *vma,
+					 const char *name)
+{
+	const char *vma_name = vma_anon_name(vma);
+
+	/* either both NULL, or pointers to same string */
+	if (vma_name == name)
+		return true;
+
+	return name && vma_name && !strcmp(name, vma_name);
+}
+#else /* CONFIG_ANON_VMA_NAME */
+static inline const char *vma_anon_name(struct vm_area_struct *vma)
+{
+	return NULL;
+}
+static inline void dup_vma_anon_name(struct vm_area_struct *orig_vma,
+			      struct vm_area_struct *new_vma) {}
+static inline void free_vma_anon_name(struct vm_area_struct *vma) {}
+static inline bool is_same_vma_anon_name(struct vm_area_struct *vma,
+					 const char *name)
+{
+	return true;
+}
+#endif  /* CONFIG_ANON_VMA_NAME */
+
 #endif
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 449b6eafc695..4d5fb84eed5e 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -890,52 +890,4 @@ typedef struct {
 	unsigned long val;
 } swp_entry_t;
 
-#ifdef CONFIG_ANON_VMA_NAME
-/*
- * mmap_lock should be read-locked when calling vma_anon_name() and while using
- * the returned pointer.
- */
-extern const char *vma_anon_name(struct vm_area_struct *vma);
-
-/*
- * mmap_lock should be read-locked for orig_vma->vm_mm.
- * mmap_lock should be write-locked for new_vma->vm_mm or new_vma should be
- * isolated.
- */
-extern void dup_vma_anon_name(struct vm_area_struct *orig_vma,
-			      struct vm_area_struct *new_vma);
-
-/*
- * mmap_lock should be write-locked or vma should have been isolated under
- * write-locked mmap_lock protection.
- */
-extern void free_vma_anon_name(struct vm_area_struct *vma);
-
-/* mmap_lock should be read-locked */
-static inline bool is_same_vma_anon_name(struct vm_area_struct *vma,
-					 const char *name)
-{
-	const char *vma_name = vma_anon_name(vma);
-
-	/* either both NULL, or pointers to same string */
-	if (vma_name == name)
-		return true;
-
-	return name && vma_name && !strcmp(name, vma_name);
-}
-#else /* CONFIG_ANON_VMA_NAME */
-static inline const char *vma_anon_name(struct vm_area_struct *vma)
-{
-	return NULL;
-}
-static inline void dup_vma_anon_name(struct vm_area_struct *orig_vma,
-			      struct vm_area_struct *new_vma) {}
-static inline void free_vma_anon_name(struct vm_area_struct *vma) {}
-static inline bool is_same_vma_anon_name(struct vm_area_struct *vma,
-					 const char *name)
-{
-	return true;
-}
-#endif  /* CONFIG_ANON_VMA_NAME */
-
 #endif /* _LINUX_MM_TYPES_H */
diff --git a/kernel/fork.c b/kernel/fork.c
index 4cf20b5f2da3..75737e566441 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -42,6 +42,7 @@
 #include <linux/mmu_notifier.h>
 #include <linux/fs.h>
 #include <linux/mm.h>
+#include <linux/mm_inline.h>
 #include <linux/vmacache.h>
 #include <linux/nsproxy.h>
 #include <linux/capability.h>
diff --git a/mm/madvise.c b/mm/madvise.c
index c63aacbbfa78..5604064df464 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -18,6 +18,7 @@
 #include <linux/fadvise.h>
 #include <linux/sched.h>
 #include <linux/sched/mm.h>
+#include <linux/mm_inline.h>
 #include <linux/string.h>
 #include <linux/uio.h>
 #include <linux/ksm.h>
diff --git a/mm/mmap.c b/mm/mmap.c
index 85edb0011453..77733b113c40 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -13,6 +13,7 @@
 #include <linux/slab.h>
 #include <linux/backing-dev.h>
 #include <linux/mm.h>
+#include <linux/mm_inline.h>
 #include <linux/vmacache.h>
 #include <linux/shm.h>
 #include <linux/mman.h>