diff options
Diffstat (limited to 'include/linux/rmap.h')
| -rw-r--r-- | include/linux/rmap.h | 35 |
1 files changed, 31 insertions, 4 deletions
diff --git a/include/linux/rmap.h b/include/linux/rmap.h index b019ae64e2ab..62da2001d55c 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -37,7 +37,27 @@ struct anon_vma { * is serialized by a system wide lock only visible to * mm_take_all_locks() (mm_all_locks_mutex). */ - struct list_head head; /* List of private "related" vmas */ + struct list_head head; /* Chain of private "related" vmas */ +}; + +/* + * The copy-on-write semantics of fork mean that an anon_vma + * can become associated with multiple processes. Furthermore, + * each child process will have its own anon_vma, where new + * pages for that process are instantiated. + * + * This structure allows us to find the anon_vmas associated + * with a VMA, or the VMAs associated with an anon_vma. + * The "same_vma" list contains the anon_vma_chains linking + * all the anon_vmas associated with this VMA. + * The "same_anon_vma" list contains the anon_vma_chains + * which link all the VMAs associated with this anon_vma. + */ +struct anon_vma_chain { + struct vm_area_struct *vma; + struct anon_vma *anon_vma; + struct list_head same_vma; /* locked by mmap_sem & page_table_lock */ + struct list_head same_anon_vma; /* locked by anon_vma->lock */ }; #ifdef CONFIG_MMU @@ -89,12 +109,19 @@ static inline void anon_vma_unlock(struct vm_area_struct *vma) */ void anon_vma_init(void); /* create anon_vma_cachep */ int anon_vma_prepare(struct vm_area_struct *); -void __anon_vma_merge(struct vm_area_struct *, struct vm_area_struct *); -void anon_vma_unlink(struct vm_area_struct *); -void anon_vma_link(struct vm_area_struct *); +void unlink_anon_vmas(struct vm_area_struct *); +int anon_vma_clone(struct vm_area_struct *, struct vm_area_struct *); +int anon_vma_fork(struct vm_area_struct *, struct vm_area_struct *); void __anon_vma_link(struct vm_area_struct *); void anon_vma_free(struct anon_vma *); +static inline void anon_vma_merge(struct vm_area_struct *vma, + struct vm_area_struct *next) +{ + VM_BUG_ON(vma->anon_vma != next->anon_vma); + unlink_anon_vmas(next); +} + /* * rmap interfaces called when adding or removing pte of page */ |