mm: refactor vm_area_struct::anon_vma_name usage code

Avoid mixing strings and their anon_vma_name referenced pointers by
using struct anon_vma_name whenever possible.  This simplifies the code
and allows easier sharing of anon_vma_name structures when they
represent the same name.

[surenb@google.com: fix comment]

Link: https://lkml.kernel.org/r/20220223153613.835563-1-surenb@google.com
Link: https://lkml.kernel.org/r/20220224231834.1481408-1-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Suggested-by: Matthew Wilcox <willy@infradead.org>
Suggested-by: Michal Hocko <mhocko@suse.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Colin Cross <ccross@google.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Alexey Gladkov <legion@kernel.org>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Chris Hyser <chris.hyser@oracle.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Peter Collingbourne <pcc@google.com>
Cc: Xiaofeng Cao <caoxiaofeng@yulong.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Cyrill Gorcunov <gorcunov@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 6e97ed775074c893d323afd054e1fd62f019aa84..2c48b1eaaa9c7f29f5d30e752889060421b3a469 100644 (file)
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -309,7 +309,7 @@ show_map_vma(struct seq_file *m, struct vm_area_struct *vma)
 
        name = arch_vma_name(vma);
        if (!name) {
-               const char *anon_name;
+               struct anon_vma_name *anon_name;
 
                if (!mm) {
                        name = "[vdso]";
@@ -327,10 +327,10 @@ show_map_vma(struct seq_file *m, struct vm_area_struct *vma)
                        goto done;
                }
 
-               anon_name = vma_anon_name(vma);
+               anon_name = anon_vma_name(vma);
                if (anon_name) {
                        seq_pad(m, ' ');
-                       seq_printf(m, "[anon:%s]", anon_name);
+                       seq_printf(m, "[anon:%s]", anon_name->name);
                }
        }
 

diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index e26b10132d47e2a49edf6da88ad109ea3141b657..8e03b3d3f5fa854be7d4ed6b58898d7b44a256f1 100644 (file)
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -878,7 +878,7 @@ static int userfaultfd_release(struct inode *inode, struct file *file)
                                 new_flags, vma->anon_vma,
                                 vma->vm_file, vma->vm_pgoff,
                                 vma_policy(vma),
-                                NULL_VM_UFFD_CTX, vma_anon_name(vma));
+                                NULL_VM_UFFD_CTX, anon_vma_name(vma));
                if (prev)
                        vma = prev;
                else
@@ -1438,7 +1438,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
                                 vma->anon_vma, vma->vm_file, vma->vm_pgoff,
                                 vma_policy(vma),
                                 ((struct vm_userfaultfd_ctx){ ctx }),
-                                vma_anon_name(vma));
+                                anon_vma_name(vma));
                if (prev) {
                        vma = prev;
                        goto next;
@@ -1615,7 +1615,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx,
                prev = vma_merge(mm, prev, start, vma_end, new_flags,
                                 vma->anon_vma, vma->vm_file, vma->vm_pgoff,
                                 vma_policy(vma),
-                                NULL_VM_UFFD_CTX, vma_anon_name(vma));
+                                NULL_VM_UFFD_CTX, anon_vma_name(vma));
                if (prev) {
                        vma = prev;
                        goto next;

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 213cc569b19223c8738d980bf57ec0308a41de93..5744a3fc47169a512880561aa2ea91ebad8772fd 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2626,7 +2626,7 @@ static inline int vma_adjust(struct vm_area_struct *vma, unsigned long start,
 extern struct vm_area_struct *vma_merge(struct mm_struct *,
        struct vm_area_struct *prev, unsigned long addr, unsigned long end,
        unsigned long vm_flags, struct anon_vma *, struct file *, pgoff_t,
-       struct mempolicy *, struct vm_userfaultfd_ctx, const char *);
+       struct mempolicy *, struct vm_userfaultfd_ctx, struct anon_vma_name *);
 extern struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *);
 extern int __split_vma(struct mm_struct *, struct vm_area_struct *,
        unsigned long addr, int new_below);
@@ -3372,11 +3372,12 @@ static inline int seal_check_future_write(int seals, struct vm_area_struct *vma)
 
 #ifdef CONFIG_ANON_VMA_NAME
 int madvise_set_anon_name(struct mm_struct *mm, unsigned long start,
-                         unsigned long len_in, const char *name);
+                         unsigned long len_in,
+                         struct anon_vma_name *anon_name);
 #else
 static inline int
 madvise_set_anon_name(struct mm_struct *mm, unsigned long start,
-                     unsigned long len_in, const char *name) {
+                     unsigned long len_in, struct anon_vma_name *anon_name) {
        return 0;
 }
 #endif

diff --git a/include/linux/mm_inline.h b/include/linux/mm_inline.h
index b725839dfe715a4e83ae948fe62d7d1417afdcdd..dd3accaa4e6dfc82e06d32637db90a8aaea31a3e 100644 (file)
--- a/include/linux/mm_inline.h
+++ b/include/linux/mm_inline.h
@@ -140,50 +140,81 @@ static __always_inline void del_page_from_lru_list(struct page *page,
 
 #ifdef CONFIG_ANON_VMA_NAME
 /*
- * mmap_lock should be read-locked when calling vma_anon_name() and while using
- * the returned pointer.
+ * mmap_lock should be read-locked when calling anon_vma_name(). Caller should
+ * either keep holding the lock while using the returned pointer or it should
+ * raise anon_vma_name refcount before releasing the lock.
  */
-extern const char *vma_anon_name(struct vm_area_struct *vma);
+extern struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma);
+extern struct anon_vma_name *anon_vma_name_alloc(const char *name);
+extern void anon_vma_name_free(struct kref *kref);
 
-/*
- * 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 read-locked */
+static inline void anon_vma_name_get(struct anon_vma_name *anon_name)
+{
+       if (anon_name)
+               kref_get(&anon_name->kref);
+}
 
-/*
- * 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);
+static inline void anon_vma_name_put(struct anon_vma_name *anon_name)
+{
+       if (anon_name)
+               kref_put(&anon_name->kref, anon_vma_name_free);
+}
 
-/* mmap_lock should be read-locked */
-static inline bool is_same_vma_anon_name(struct vm_area_struct *vma,
-                                        const char *name)
+static inline void dup_anon_vma_name(struct vm_area_struct *orig_vma,
+                                    struct vm_area_struct *new_vma)
+{
+       struct anon_vma_name *anon_name = anon_vma_name(orig_vma);
+
+       if (anon_name) {
+               anon_vma_name_get(anon_name);
+               new_vma->anon_name = anon_name;
+       }
+}
+
+static inline void free_anon_vma_name(struct vm_area_struct *vma)
 {
-       const char *vma_name = vma_anon_name(vma);
+       /*
+        * Not using anon_vma_name because it generates a warning if mmap_lock
+        * is not held, which might be the case here.
+        */
+       if (!vma->vm_file)
+               anon_vma_name_put(vma->anon_name);
+}
 
-       /* either both NULL, or pointers to same string */
-       if (vma_name == name)
+static inline bool anon_vma_name_eq(struct anon_vma_name *anon_name1,
+                                   struct anon_vma_name *anon_name2)
+{
+       if (anon_name1 == anon_name2)
                return true;
 
-       return name && vma_name && !strcmp(name, vma_name);
+       return anon_name1 && anon_name2 &&
+               !strcmp(anon_name1->name, anon_name2->name);
 }
+
 #else /* CONFIG_ANON_VMA_NAME */
-static inline const char *vma_anon_name(struct vm_area_struct *vma)
+static inline struct anon_vma_name *anon_vma_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)
+
+static inline struct anon_vma_name *anon_vma_name_alloc(const char *name)
+{
+       return NULL;
+}
+
+static inline void anon_vma_name_get(struct anon_vma_name *anon_name) {}
+static inline void anon_vma_name_put(struct anon_vma_name *anon_name) {}
+static inline void dup_anon_vma_name(struct vm_area_struct *orig_vma,
+                                    struct vm_area_struct *new_vma) {}
+static inline void free_anon_vma_name(struct vm_area_struct *vma) {}
+
+static inline bool anon_vma_name_eq(struct anon_vma_name *anon_name1,
+                                   struct anon_vma_name *anon_name2)
 {
        return true;
 }
+
 #endif  /* CONFIG_ANON_VMA_NAME */
 
 static inline void init_tlb_flush_pending(struct mm_struct *mm)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 5140e5feb486613cdf42df80b4403c68480db8c6..0f549870da6a0d58fdba728fbc7cb0c195b0ec43 100644 (file)
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -416,7 +416,10 @@ struct vm_area_struct {
                        struct rb_node rb;
                        unsigned long rb_subtree_last;
                } shared;
-               /* Serialized by mmap_sem. */
+               /*
+                * Serialized by mmap_sem. Never use directly because it is
+                * valid only when vm_file is NULL. Use anon_vma_name instead.
+                */
                struct anon_vma_name *anon_name;
        };
 

diff --git a/kernel/fork.c b/kernel/fork.c
index a024bf6254df895e7920372d4ef0cb94ac6e6d50..f1e89007f22889c627aadb53934b27cd66b29afe 100644 (file)
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -366,14 +366,14 @@ struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig)
                *new = data_race(*orig);
                INIT_LIST_HEAD(&new->anon_vma_chain);
                new->vm_next = new->vm_prev = NULL;
-               dup_vma_anon_name(orig, new);
+               dup_anon_vma_name(orig, new);
        }
        return new;
 }
 
 void vm_area_free(struct vm_area_struct *vma)
 {
-       free_vma_anon_name(vma);
+       free_anon_vma_name(vma);
        kmem_cache_free(vm_area_cachep, vma);
 }
 

diff --git a/kernel/sys.c b/kernel/sys.c
index 97dc9e5d6bf92ca7e18c8f474d926e8c51d46679..5b0e172c4d47b2d49a4e58190a9cc23257b06025 100644 (file)
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -7,6 +7,7 @@
 
 #include <linux/export.h>
 #include <linux/mm.h>
+#include <linux/mm_inline.h>
 #include <linux/utsname.h>
 #include <linux/mman.h>
 #include <linux/reboot.h>
@@ -2286,15 +2287,16 @@ static int prctl_set_vma(unsigned long opt, unsigned long addr,
 {
        struct mm_struct *mm = current->mm;
        const char __user *uname;
-       char *name, *pch;
+       struct anon_vma_name *anon_name = NULL;
        int error;
 
        switch (opt) {
        case PR_SET_VMA_ANON_NAME:
                uname = (const char __user *)arg;
                if (uname) {
-                       name = strndup_user(uname, ANON_VMA_NAME_MAX_LEN);
+                       char *name, *pch;
 
+                       name = strndup_user(uname, ANON_VMA_NAME_MAX_LEN);
                        if (IS_ERR(name))
                                return PTR_ERR(name);
 
@@ -2304,15 +2306,18 @@ static int prctl_set_vma(unsigned long opt, unsigned long addr,
                                        return -EINVAL;
                                }
                        }
-               } else {
-                       /* Reset the name */
-                       name = NULL;
+                       /* anon_vma has its own copy */
+                       anon_name = anon_vma_name_alloc(name);
+                       kfree(name);
+                       if (!anon_name)
+                               return -ENOMEM;
+
                }
 
                mmap_write_lock(mm);
-               error = madvise_set_anon_name(mm, addr, size, name);
+               error = madvise_set_anon_name(mm, addr, size, anon_name);
                mmap_write_unlock(mm);
-               kfree(name);
+               anon_vma_name_put(anon_name);
                break;
        default:
                error = -EINVAL;

diff --git a/mm/madvise.c b/mm/madvise.c
index 5604064df4646e786d1c9e2fcf0a35eb71f622ba..081b1cded21e54ccedb5efea25ad67b588f8fedd 100644 (file)
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -65,7 +65,7 @@ static int madvise_need_mmap_write(int behavior)
 }
 
 #ifdef CONFIG_ANON_VMA_NAME
-static struct anon_vma_name *anon_vma_name_alloc(const char *name)
+struct anon_vma_name *anon_vma_name_alloc(const char *name)
 {
        struct anon_vma_name *anon_name;
        size_t count;
@@ -81,78 +81,49 @@ static struct anon_vma_name *anon_vma_name_alloc(const char *name)
        return anon_name;
 }
 
-static void vma_anon_name_free(struct kref *kref)
+void anon_vma_name_free(struct kref *kref)
 {
        struct anon_vma_name *anon_name =
                        container_of(kref, struct anon_vma_name, kref);
        kfree(anon_name);
 }
 
-static inline bool has_vma_anon_name(struct vm_area_struct *vma)
+struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma)
 {
-       return !vma->vm_file && vma->anon_name;
-}
-
-const char *vma_anon_name(struct vm_area_struct *vma)
-{
-       if (!has_vma_anon_name(vma))
-               return NULL;
-
        mmap_assert_locked(vma->vm_mm);
 
-       return vma->anon_name->name;
-}
-
-void dup_vma_anon_name(struct vm_area_struct *orig_vma,
-                      struct vm_area_struct *new_vma)
-{
-       if (!has_vma_anon_name(orig_vma))
-               return;
-
-       kref_get(&orig_vma->anon_name->kref);
-       new_vma->anon_name = orig_vma->anon_name;
-}
-
-void free_vma_anon_name(struct vm_area_struct *vma)
-{
-       struct anon_vma_name *anon_name;
-
-       if (!has_vma_anon_name(vma))
-               return;
+       if (vma->vm_file)
+               return NULL;
 
-       anon_name = vma->anon_name;
-       vma->anon_name = NULL;
-       kref_put(&anon_name->kref, vma_anon_name_free);
+       return vma->anon_name;
 }
 
 /* mmap_lock should be write-locked */
-static int replace_vma_anon_name(struct vm_area_struct *vma, const char *name)
+static int replace_anon_vma_name(struct vm_area_struct *vma,
+                                struct anon_vma_name *anon_name)
 {
-       const char *anon_name;
+       struct anon_vma_name *orig_name = anon_vma_name(vma);
 
-       if (!name) {
-               free_vma_anon_name(vma);
+       if (!anon_name) {
+               vma->anon_name = NULL;
+               anon_vma_name_put(orig_name);
                return 0;
        }
 
-       anon_name = vma_anon_name(vma);
-       if (anon_name) {
-               /* Same name, nothing to do here */
-               if (!strcmp(name, anon_name))
-                       return 0;
+       if (anon_vma_name_eq(orig_name, anon_name))
+               return 0;
 
-               free_vma_anon_name(vma);
-       }
-       vma->anon_name = anon_vma_name_alloc(name);
-       if (!vma->anon_name)
-               return -ENOMEM;
+       anon_vma_name_get(anon_name);
+       vma->anon_name = anon_name;
+       anon_vma_name_put(orig_name);
 
        return 0;
 }
 #else /* CONFIG_ANON_VMA_NAME */
-static int replace_vma_anon_name(struct vm_area_struct *vma, const char *name)
+static int replace_anon_vma_name(struct vm_area_struct *vma,
+                                struct anon_vma_name *anon_name)
 {
-       if (name)
+       if (anon_name)
                return -EINVAL;
 
        return 0;
@@ -165,13 +136,13 @@ static int replace_vma_anon_name(struct vm_area_struct *vma, const char *name)
 static int madvise_update_vma(struct vm_area_struct *vma,
                              struct vm_area_struct **prev, unsigned long start,
                              unsigned long end, unsigned long new_flags,
-                             const char *name)
+                             struct anon_vma_name *anon_name)
 {
        struct mm_struct *mm = vma->vm_mm;
        int error;
        pgoff_t pgoff;
 
-       if (new_flags == vma->vm_flags && is_same_vma_anon_name(vma, name)) {
+       if (new_flags == vma->vm_flags && anon_vma_name_eq(anon_vma_name(vma), anon_name)) {
                *prev = vma;
                return 0;
        }
@@ -179,7 +150,7 @@ static int madvise_update_vma(struct vm_area_struct *vma,
        pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
        *prev = vma_merge(mm, *prev, start, end, new_flags, vma->anon_vma,
                          vma->vm_file, pgoff, vma_policy(vma),
-                         vma->vm_userfaultfd_ctx, name);
+                         vma->vm_userfaultfd_ctx, anon_name);
        if (*prev) {
                vma = *prev;
                goto success;
@@ -209,7 +180,7 @@ success:
         */
        vma->vm_flags = new_flags;
        if (!vma->vm_file) {
-               error = replace_vma_anon_name(vma, name);
+               error = replace_anon_vma_name(vma, anon_name);
                if (error)
                        return error;
        }
@@ -1041,7 +1012,7 @@ static int madvise_vma_behavior(struct vm_area_struct *vma,
        }
 
        error = madvise_update_vma(vma, prev, start, end, new_flags,
-                                  vma_anon_name(vma));
+                                  anon_vma_name(vma));
 
 out:
        /*
@@ -1225,7 +1196,7 @@ int madvise_walk_vmas(struct mm_struct *mm, unsigned long start,
 static int madvise_vma_anon_name(struct vm_area_struct *vma,
                                 struct vm_area_struct **prev,
                                 unsigned long start, unsigned long end,
-                                unsigned long name)
+                                unsigned long anon_name)
 {
        int error;
 
@@ -1234,7 +1205,7 @@ static int madvise_vma_anon_name(struct vm_area_struct *vma,
                return -EBADF;
 
        error = madvise_update_vma(vma, prev, start, end, vma->vm_flags,
-                                  (const char *)name);
+                                  (struct anon_vma_name *)anon_name);
 
        /*
         * madvise() returns EAGAIN if kernel resources, such as
@@ -1246,7 +1217,7 @@ static int madvise_vma_anon_name(struct vm_area_struct *vma,
 }
 
 int madvise_set_anon_name(struct mm_struct *mm, unsigned long start,
-                         unsigned long len_in, const char *name)
+                         unsigned long len_in, struct anon_vma_name *anon_name)
 {
        unsigned long end;
        unsigned long len;
@@ -1266,7 +1237,7 @@ int madvise_set_anon_name(struct mm_struct *mm, unsigned long start,
        if (end == start)
                return 0;
 
-       return madvise_walk_vmas(mm, start, end, (unsigned long)name,
+       return madvise_walk_vmas(mm, start, end, (unsigned long)anon_name,
                                 madvise_vma_anon_name);
 }
 #endif /* CONFIG_ANON_VMA_NAME */

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 028e8dd82b4425db7582c9dca713a1f77b86b4fe..69284d3b5e53f868c77da3ecd32aa3a436e8d359 100644 (file)
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -814,7 +814,7 @@ static int mbind_range(struct mm_struct *mm, unsigned long start,
                prev = vma_merge(mm, prev, vmstart, vmend, vma->vm_flags,
                                 vma->anon_vma, vma->vm_file, pgoff,
                                 new_pol, vma->vm_userfaultfd_ctx,
-                                vma_anon_name(vma));
+                                anon_vma_name(vma));
                if (prev) {
                        vma = prev;
                        next = vma->vm_next;

diff --git a/mm/mlock.c b/mm/mlock.c
index 8f584eddd305380d3aae8fb810998e9530468f42..25934e7db3e103e98baa9f9db7083944a1265e2d 100644 (file)
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -512,7 +512,7 @@ static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev,
        pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
        *prev = vma_merge(mm, *prev, start, end, newflags, vma->anon_vma,
                          vma->vm_file, pgoff, vma_policy(vma),
-                         vma->vm_userfaultfd_ctx, vma_anon_name(vma));
+                         vma->vm_userfaultfd_ctx, anon_vma_name(vma));
        if (*prev) {
                vma = *prev;
                goto success;

diff --git a/mm/mmap.c b/mm/mmap.c
index d445c1b9d60650b58c39c3688405567598c71fd9..f61a15474dd6d5ae25039bde9087533cdab17614 100644 (file)
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1031,7 +1031,7 @@ again:
 static inline int is_mergeable_vma(struct vm_area_struct *vma,
                                struct file *file, unsigned long vm_flags,
                                struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
-                               const char *anon_name)
+                               struct anon_vma_name *anon_name)
 {
        /*
         * VM_SOFTDIRTY should not prevent from VMA merging, if we
@@ -1049,7 +1049,7 @@ static inline int is_mergeable_vma(struct vm_area_struct *vma,
                return 0;
        if (!is_mergeable_vm_userfaultfd_ctx(vma, vm_userfaultfd_ctx))
                return 0;
-       if (!is_same_vma_anon_name(vma, anon_name))
+       if (!anon_vma_name_eq(anon_vma_name(vma), anon_name))
                return 0;
        return 1;
 }
@@ -1084,7 +1084,7 @@ can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
                     struct anon_vma *anon_vma, struct file *file,
                     pgoff_t vm_pgoff,
                     struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
-                    const char *anon_name)
+                    struct anon_vma_name *anon_name)
 {
        if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx, anon_name) &&
            is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) {
@@ -1106,7 +1106,7 @@ can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
                    struct anon_vma *anon_vma, struct file *file,
                    pgoff_t vm_pgoff,
                    struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
-                   const char *anon_name)
+                   struct anon_vma_name *anon_name)
 {
        if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx, anon_name) &&
            is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) {
@@ -1167,7 +1167,7 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm,
                        struct anon_vma *anon_vma, struct file *file,
                        pgoff_t pgoff, struct mempolicy *policy,
                        struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
-                       const char *anon_name)
+                       struct anon_vma_name *anon_name)
 {
        pgoff_t pglen = (end - addr) >> PAGE_SHIFT;
        struct vm_area_struct *area, *next;
@@ -3256,7 +3256,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
                return NULL;    /* should never get here */
        new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags,
                            vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
-                           vma->vm_userfaultfd_ctx, vma_anon_name(vma));
+                           vma->vm_userfaultfd_ctx, anon_vma_name(vma));
        if (new_vma) {
                /*
                 * Source vma may have been merged into new_vma

diff --git a/mm/mprotect.c b/mm/mprotect.c
index 5ca3fbcb149520f4ea8692f3dfbc7368fe8b4f1a..2887644fd15057db5669997f0ece69dc82427dd1 100644 (file)
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -464,7 +464,7 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
        pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
        *pprev = vma_merge(mm, *pprev, start, end, newflags,
                           vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
-                          vma->vm_userfaultfd_ctx, vma_anon_name(vma));
+                          vma->vm_userfaultfd_ctx, anon_vma_name(vma));
        if (*pprev) {
                vma = *pprev;
                VM_WARN_ON((vma->vm_flags ^ newflags) & ~VM_SOFTDIRTY);