diff options
Diffstat (limited to 'mm/vma_init.c')
| -rw-r--r-- | mm/vma_init.c | 50 |
1 files changed, 50 insertions, 0 deletions
diff --git a/mm/vma_init.c b/mm/vma_init.c index 967ca85179864..8e53c7943561e 100644 --- a/mm/vma_init.c +++ b/mm/vma_init.c @@ -71,7 +71,51 @@ static void vm_area_init_from(const struct vm_area_struct *src, #ifdef CONFIG_NUMA dest->vm_policy = src->vm_policy; #endif +#ifdef __HAVE_PFNMAP_TRACKING + dest->pfnmap_track_ctx = NULL; +#endif +} + +#ifdef __HAVE_PFNMAP_TRACKING +static inline int vma_pfnmap_track_ctx_dup(struct vm_area_struct *orig, + struct vm_area_struct *new) +{ + struct pfnmap_track_ctx *ctx = orig->pfnmap_track_ctx; + + if (likely(!ctx)) + return 0; + + /* + * We don't expect to ever hit this. If ever required, we would have + * to duplicate the tracking. + */ + if (unlikely(kref_read(&ctx->kref) >= REFCOUNT_MAX)) + return -ENOMEM; + kref_get(&ctx->kref); + new->pfnmap_track_ctx = ctx; + return 0; +} + +static inline void vma_pfnmap_track_ctx_release(struct vm_area_struct *vma) +{ + struct pfnmap_track_ctx *ctx = vma->pfnmap_track_ctx; + + if (likely(!ctx)) + return; + + kref_put(&ctx->kref, pfnmap_track_ctx_release); + vma->pfnmap_track_ctx = NULL; +} +#else +static inline int vma_pfnmap_track_ctx_dup(struct vm_area_struct *orig, + struct vm_area_struct *new) +{ + return 0; } +static inline void vma_pfnmap_track_ctx_release(struct vm_area_struct *vma) +{ +} +#endif struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig) { @@ -83,6 +127,11 @@ struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig) ASSERT_EXCLUSIVE_WRITER(orig->vm_flags); ASSERT_EXCLUSIVE_WRITER(orig->vm_file); vm_area_init_from(orig, new); + + if (vma_pfnmap_track_ctx_dup(orig, new)) { + kmem_cache_free(vm_area_cachep, new); + return NULL; + } vma_lock_init(new, true); INIT_LIST_HEAD(&new->anon_vma_chain); vma_numab_state_init(new); @@ -97,5 +146,6 @@ void vm_area_free(struct vm_area_struct *vma) vma_assert_detached(vma); vma_numab_state_free(vma); free_anon_vma_name(vma); + vma_pfnmap_track_ctx_release(vma); kmem_cache_free(vm_area_cachep, vma); } |