diff options
Diffstat (limited to 'tools/testing/vma/vma_internal.h')
| -rw-r--r-- | tools/testing/vma/vma_internal.h | 131 |
1 files changed, 60 insertions, 71 deletions
diff --git a/tools/testing/vma/vma_internal.h b/tools/testing/vma/vma_internal.h index 1eae23039854..572ab2cea763 100644 --- a/tools/testing/vma/vma_internal.h +++ b/tools/testing/vma/vma_internal.h @@ -25,7 +25,7 @@ #include <linux/maple_tree.h> #include <linux/mm.h> #include <linux/rbtree.h> -#include <linux/rwsem.h> +#include <linux/refcount.h> extern unsigned long stack_guard_gap; #ifdef CONFIG_MMU @@ -135,10 +135,6 @@ typedef __bitwise unsigned int vm_fault_t; */ #define pr_warn_once pr_err -typedef struct refcount_struct { - atomic_t refs; -} refcount_t; - struct kref { refcount_t refcount; }; @@ -233,15 +229,12 @@ struct mm_struct { unsigned long flags; /* Must use atomic bitops to access */ }; -struct vma_lock { - struct rw_semaphore lock; -}; - - struct file { struct address_space *f_mapping; }; +#define VMA_LOCK_OFFSET 0x40000000 + struct vm_area_struct { /* The first cache line has the info for VMA tree walking. */ @@ -269,16 +262,13 @@ struct vm_area_struct { }; #ifdef CONFIG_PER_VMA_LOCK - /* Flag to indicate areas detached from the mm->mm_mt tree */ - bool detached; - /* * Can only be written (using WRITE_ONCE()) while holding both: * - mmap_lock (in write mode) - * - vm_lock->lock (in write mode) + * - vm_refcnt bit at VMA_LOCK_OFFSET is set * Can be read reliably while holding one of: * - mmap_lock (in read or write mode) - * - vm_lock->lock (in read or write mode) + * - vm_refcnt bit at VMA_LOCK_OFFSET is set or vm_refcnt > 1 * Can be read unreliably (using READ_ONCE()) for pessimistic bailout * while holding nothing (except RCU to keep the VMA struct allocated). * @@ -287,20 +277,9 @@ struct vm_area_struct { * slowpath. */ unsigned int vm_lock_seq; - struct vma_lock *vm_lock; #endif /* - * For areas with an address space and backing store, - * linkage into the address_space->i_mmap interval tree. - * - */ - 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 * list, after a COW of one of the file pages. A MAP_SHARED vma * can only be in the i_mmap tree. An anonymous MAP_PRIVATE, stack @@ -319,14 +298,6 @@ 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_lock. Use anon_vma_name to access. - */ - struct anon_vma_name *anon_name; -#endif #ifdef CONFIG_SWAP atomic_long_t swap_readahead_info; #endif @@ -339,6 +310,27 @@ struct vm_area_struct { #ifdef CONFIG_NUMA_BALANCING struct vma_numab_state *numab_state; /* NUMA Balancing state */ #endif +#ifdef CONFIG_PER_VMA_LOCK + /* Unstable RCU readers are allowed to read this. */ + refcount_t vm_refcnt; +#endif + /* + * For areas with an address space and backing store, + * linkage into the address_space->i_mmap interval tree. + * + */ + struct { + struct rb_node rb; + unsigned long rb_subtree_last; + } shared; +#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_lock. Use anon_vma_name to access. + */ + struct anon_vma_name *anon_name; +#endif struct vm_userfaultfd_ctx vm_userfaultfd_ctx; } __randomize_layout; @@ -464,26 +456,40 @@ static inline struct vm_area_struct *vma_next(struct vma_iterator *vmi) return mas_find(&vmi->mas, ULONG_MAX); } -static inline bool vma_lock_alloc(struct vm_area_struct *vma) +/* + * WARNING: to avoid racing with vma_mark_attached()/vma_mark_detached(), these + * assertions should be made either under mmap_write_lock or when the object + * has been isolated under mmap_write_lock, ensuring no competing writers. + */ +static inline void vma_assert_attached(struct vm_area_struct *vma) { - vma->vm_lock = calloc(1, sizeof(struct vma_lock)); - - if (!vma->vm_lock) - return false; - - init_rwsem(&vma->vm_lock->lock); - vma->vm_lock_seq = UINT_MAX; + WARN_ON_ONCE(!refcount_read(&vma->vm_refcnt)); +} - return true; +static inline void vma_assert_detached(struct vm_area_struct *vma) +{ + WARN_ON_ONCE(refcount_read(&vma->vm_refcnt)); } static inline void vma_assert_write_locked(struct vm_area_struct *); -static inline void vma_mark_detached(struct vm_area_struct *vma, bool detached) +static inline void vma_mark_attached(struct vm_area_struct *vma) { - /* When detaching vma should be write-locked */ - if (detached) - vma_assert_write_locked(vma); - vma->detached = detached; + vma_assert_write_locked(vma); + vma_assert_detached(vma); + refcount_set_release(&vma->vm_refcnt, 1); +} + +static inline void vma_mark_detached(struct vm_area_struct *vma) +{ + vma_assert_write_locked(vma); + vma_assert_attached(vma); + /* We are the only writer, so no need to use vma_refcount_put(). */ + if (unlikely(!refcount_dec_and_test(&vma->vm_refcnt))) { + /* + * Reader must have temporarily raised vm_refcnt but it will + * drop it without using the vma since vma is write-locked. + */ + } } extern const struct vm_operations_struct vma_dummy_vm_ops; @@ -496,7 +502,7 @@ static inline void vma_init(struct vm_area_struct *vma, struct mm_struct *mm) vma->vm_mm = mm; vma->vm_ops = &vma_dummy_vm_ops; INIT_LIST_HEAD(&vma->anon_vma_chain); - vma_mark_detached(vma, false); + vma->vm_lock_seq = UINT_MAX; } static inline struct vm_area_struct *vm_area_alloc(struct mm_struct *mm) @@ -507,10 +513,6 @@ static inline struct vm_area_struct *vm_area_alloc(struct mm_struct *mm) return NULL; vma_init(vma, mm); - if (!vma_lock_alloc(vma)) { - free(vma); - return NULL; - } return vma; } @@ -523,10 +525,8 @@ static inline struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig) return NULL; memcpy(new, orig, sizeof(*new)); - if (!vma_lock_alloc(new)) { - free(new); - return NULL; - } + refcount_set(&new->vm_refcnt, 0); + new->vm_lock_seq = UINT_MAX; INIT_LIST_HEAD(&new->anon_vma_chain); return new; @@ -696,20 +696,9 @@ static inline void mpol_put(struct mempolicy *) { } -static inline void vma_lock_free(struct vm_area_struct *vma) -{ - free(vma->vm_lock); -} - -static inline void __vm_area_free(struct vm_area_struct *vma) -{ - vma_lock_free(vma); - free(vma); -} - static inline void vm_area_free(struct vm_area_struct *vma) { - __vm_area_free(vma); + free(vma); } static inline void lru_add_drain(void) @@ -796,12 +785,12 @@ static inline void vma_start_write(struct vm_area_struct *vma) static inline void vma_adjust_trans_huge(struct vm_area_struct *vma, unsigned long start, unsigned long end, - long adjust_next) + struct vm_area_struct *next) { (void)vma; (void)start; (void)end; - (void)adjust_next; + (void)next; } static inline void vma_iter_free(struct vma_iterator *vmi) |