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mm: refactor vm_area_struct::anon_vma_name usage code

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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>
This commit is contained in:
Suren Baghdasaryan
2022-03-04 20:28:51 -08:00
committed by Linus Torvalds
parent ff712a627f
commit 5c26f6ac94
12 changed files with 126 additions and 115 deletions
Download Patch File Download Diff File Expand all files Collapse all files

89
include/linux/mm_inline.h
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@@ -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);
/*
* 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);
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 */
static inline bool is_same_vma_anon_name(struct vm_area_struct *vma,
const char *name)
static inline void anon_vma_name_get(struct anon_vma_name *anon_name)
{
const char *vma_name = vma_anon_name(vma);
if (anon_name)
kref_get(&anon_name->kref);
}
/* either both NULL, or pointers to same string */
if (vma_name == name)
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);
}
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)
{
/*
* 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);
}
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)