diff options
Diffstat (limited to 'kernel/fork.c')
| -rw-r--r-- | kernel/fork.c | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/kernel/fork.c b/kernel/fork.c index 364b2d4fd3efa..f9cf0f056eb6f 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -802,6 +802,36 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) #define mm_free_pgd(mm) #endif /* CONFIG_MMU */ +#ifdef CONFIG_MM_ID +static DEFINE_IDA(mm_ida); + +static inline int mm_alloc_id(struct mm_struct *mm) +{ + int ret; + + ret = ida_alloc_range(&mm_ida, MM_ID_MIN, MM_ID_MAX, GFP_KERNEL); + if (ret < 0) + return ret; + mm->mm_id = ret; + return 0; +} + +static inline void mm_free_id(struct mm_struct *mm) +{ + const mm_id_t id = mm->mm_id; + + mm->mm_id = MM_ID_DUMMY; + if (id == MM_ID_DUMMY) + return; + if (WARN_ON_ONCE(id < MM_ID_MIN || id > MM_ID_MAX)) + return; + ida_free(&mm_ida, id); +} +#else /* !CONFIG_MM_ID */ +static inline int mm_alloc_id(struct mm_struct *mm) { return 0; } +static inline void mm_free_id(struct mm_struct *mm) {} +#endif /* CONFIG_MM_ID */ + static void check_mm(struct mm_struct *mm) { int i; @@ -905,6 +935,7 @@ void __mmdrop(struct mm_struct *mm) WARN_ON_ONCE(mm == current->active_mm); mm_free_pgd(mm); + mm_free_id(mm); destroy_context(mm); mmu_notifier_subscriptions_destroy(mm); check_mm(mm); @@ -1289,6 +1320,9 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, if (mm_alloc_pgd(mm)) goto fail_nopgd; + if (mm_alloc_id(mm)) + goto fail_noid; + if (init_new_context(p, mm)) goto fail_nocontext; @@ -1308,6 +1342,8 @@ fail_pcpu: fail_cid: destroy_context(mm); fail_nocontext: + mm_free_id(mm); +fail_noid: mm_free_pgd(mm); fail_nopgd: free_mm(mm); |