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-rw-r--r--Documentation/filesystems/proc.rst8
-rw-r--r--fs/proc/task_mmu.c15
-rw-r--r--include/linux/mm.h2
-rw-r--r--include/linux/mm_types.h26
-rw-r--r--mm/madvise.c7
-rw-r--r--mm/shmem.c29
6 files changed, 57 insertions, 30 deletions
diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst
index 898c99eae8e4..b8f175ae4853 100644
--- a/Documentation/filesystems/proc.rst
+++ b/Documentation/filesystems/proc.rst
@@ -426,14 +426,16 @@ with the memory region, as the case would be with BSS (uninitialized data).
The "pathname" shows the name associated file for this mapping. If the mapping
is not associated with a file:
- ============= ====================================
+ =================== ===========================================
[heap] the heap of the program
[stack] the stack of the main process
[vdso] the "virtual dynamic shared object",
the kernel system call handler
- [anon:<name>] an anonymous mapping that has been
+ [anon:<name>] a private anonymous mapping that has been
named by userspace
- ============= ====================================
+ [anon_shmem:<name>] an anonymous shared memory mapping that has
+ been named by userspace
+ =================== ===========================================
or if empty, the mapping is anonymous.
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 8a74cdcc9af0..89338950afd3 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -274,6 +274,7 @@ static void show_vma_header_prefix(struct seq_file *m,
static void
show_map_vma(struct seq_file *m, struct vm_area_struct *vma)
{
+ struct anon_vma_name *anon_name = NULL;
struct mm_struct *mm = vma->vm_mm;
struct file *file = vma->vm_file;
vm_flags_t flags = vma->vm_flags;
@@ -293,6 +294,8 @@ show_map_vma(struct seq_file *m, struct vm_area_struct *vma)
start = vma->vm_start;
end = vma->vm_end;
show_vma_header_prefix(m, start, end, flags, pgoff, dev, ino);
+ if (mm)
+ anon_name = anon_vma_name(vma);
/*
* Print the dentry name for named mappings, and a
@@ -300,7 +303,14 @@ show_map_vma(struct seq_file *m, struct vm_area_struct *vma)
*/
if (file) {
seq_pad(m, ' ');
- seq_file_path(m, file, "\n");
+ /*
+ * If user named this anon shared memory via
+ * prctl(PR_SET_VMA ..., use the provided name.
+ */
+ if (anon_name)
+ seq_printf(m, "[anon_shmem:%s]", anon_name->name);
+ else
+ seq_file_path(m, file, "\n");
goto done;
}
@@ -312,8 +322,6 @@ show_map_vma(struct seq_file *m, struct vm_area_struct *vma)
name = arch_vma_name(vma);
if (!name) {
- struct anon_vma_name *anon_name;
-
if (!mm) {
name = "[vdso]";
goto done;
@@ -330,7 +338,6 @@ show_map_vma(struct seq_file *m, struct vm_area_struct *vma)
goto done;
}
- anon_name = anon_vma_name(vma);
if (anon_name) {
seq_pad(m, ' ');
seq_printf(m, "[anon:%s]", anon_name->name);
diff --git a/include/linux/mm.h b/include/linux/mm.h
index f873441303b7..686879dbb0bd 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -700,8 +700,10 @@ static inline unsigned long vma_iter_addr(struct vma_iterator *vmi)
* paths in userfault.
*/
bool vma_is_shmem(struct vm_area_struct *vma);
+bool vma_is_anon_shmem(struct vm_area_struct *vma);
#else
static inline bool vma_is_shmem(struct vm_area_struct *vma) { return false; }
+static inline bool vma_is_anon_shmem(struct vm_area_struct *vma) { return false; }
#endif
int vma_is_stack_for_current(struct vm_area_struct *vma);
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 6b0009e7d4ae..157c2e22cc7f 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -549,21 +549,11 @@ struct vm_area_struct {
* For areas with an address space and backing store,
* linkage into the address_space->i_mmap interval tree.
*
- * For private anonymous mappings, a pointer to a null terminated string
- * containing the name given to the vma, or NULL if unnamed.
*/
-
- union {
- struct {
- struct rb_node rb;
- unsigned long rb_subtree_last;
- } shared;
- /*
- * 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;
- };
+ struct {
+ struct rb_node rb;
+ unsigned long rb_subtree_last;
+ } shared;
/*
* A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
@@ -584,6 +574,14 @@ struct vm_area_struct {
struct file * vm_file; /* File we map to (can be NULL). */
void * vm_private_data; /* was vm_pte (shared mem) */
+#ifdef CONFIG_ANON_VMA_NAME
+ /*
+ * For private and shared anonymous mappings, a pointer to a null
+ * terminated string containing the name given to the vma, or NULL if
+ * unnamed. Serialized by mmap_sem. Use anon_vma_name to access.
+ */
+ struct anon_vma_name *anon_name;
+#endif
#ifdef CONFIG_SWAP
atomic_long_t swap_readahead_info;
#endif
diff --git a/mm/madvise.c b/mm/madvise.c
index b913ba6efc10..83b0c91a126b 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -95,9 +95,6 @@ struct anon_vma_name *anon_vma_name(struct vm_area_struct *vma)
{
mmap_assert_locked(vma->vm_mm);
- if (vma->vm_file)
- return NULL;
-
return vma->anon_name;
}
@@ -183,7 +180,7 @@ success:
* vm_flags is protected by the mmap_lock held in write mode.
*/
vma->vm_flags = new_flags;
- if (!vma->vm_file) {
+ if (!vma->vm_file || vma_is_anon_shmem(vma)) {
error = replace_anon_vma_name(vma, anon_name);
if (error)
return error;
@@ -1273,7 +1270,7 @@ static int madvise_vma_anon_name(struct vm_area_struct *vma,
int error;
/* Only anonymous mappings can be named */
- if (vma->vm_file)
+ if (vma->vm_file && !vma_is_anon_shmem(vma))
return -EBADF;
error = madvise_update_vma(vma, prev, start, end, vma->vm_flags,
diff --git a/mm/shmem.c b/mm/shmem.c
index 7428ae3fa4b9..f418d21205be 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -237,11 +237,17 @@ static const struct inode_operations shmem_inode_operations;
static const struct inode_operations shmem_dir_inode_operations;
static const struct inode_operations shmem_special_inode_operations;
static const struct vm_operations_struct shmem_vm_ops;
+static const struct vm_operations_struct shmem_anon_vm_ops;
static struct file_system_type shmem_fs_type;
+bool vma_is_anon_shmem(struct vm_area_struct *vma)
+{
+ return vma->vm_ops == &shmem_anon_vm_ops;
+}
+
bool vma_is_shmem(struct vm_area_struct *vma)
{
- return vma->vm_ops == &shmem_vm_ops;
+ return vma_is_anon_shmem(vma) || vma->vm_ops == &shmem_vm_ops;
}
static LIST_HEAD(shmem_swaplist);
@@ -2263,7 +2269,8 @@ out_nomem:
static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
{
- struct shmem_inode_info *info = SHMEM_I(file_inode(file));
+ struct inode *inode = file_inode(file);
+ struct shmem_inode_info *info = SHMEM_I(inode);
int ret;
ret = seal_check_future_write(info->seals, vma);
@@ -2274,7 +2281,11 @@ static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
vma->vm_flags |= VM_MTE_ALLOWED;
file_accessed(file);
- vma->vm_ops = &shmem_vm_ops;
+ /* This is anonymous shared memory if it is unlinked at the time of mmap */
+ if (inode->i_nlink)
+ vma->vm_ops = &shmem_vm_ops;
+ else
+ vma->vm_ops = &shmem_anon_vm_ops;
return 0;
}
@@ -3988,6 +3999,15 @@ static const struct vm_operations_struct shmem_vm_ops = {
#endif
};
+static const struct vm_operations_struct shmem_anon_vm_ops = {
+ .fault = shmem_fault,
+ .map_pages = filemap_map_pages,
+#ifdef CONFIG_NUMA
+ .set_policy = shmem_set_policy,
+ .get_policy = shmem_get_policy,
+#endif
+};
+
int shmem_init_fs_context(struct fs_context *fc)
{
struct shmem_options *ctx;
@@ -4163,6 +4183,7 @@ void shmem_truncate_range(struct inode *inode, loff_t lstart, loff_t lend)
EXPORT_SYMBOL_GPL(shmem_truncate_range);
#define shmem_vm_ops generic_file_vm_ops
+#define shmem_anon_vm_ops generic_file_vm_ops
#define shmem_file_operations ramfs_file_operations
#define shmem_get_inode(sb, dir, mode, dev, flags) ramfs_get_inode(sb, dir, mode, dev)
#define shmem_acct_size(flags, size) 0
@@ -4268,7 +4289,7 @@ int shmem_zero_setup(struct vm_area_struct *vma)
if (vma->vm_file)
fput(vma->vm_file);
vma->vm_file = file;
- vma->vm_ops = &shmem_vm_ops;
+ vma->vm_ops = &shmem_anon_vm_ops;
return 0;
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-15 17:09:57 +0000