mm initialization on fork/exec is spread all over the place, which makes the code look inconsistent. We have mm_init(), which is supposed to init/nullify mm's internals, but it doesn't init all the fields it should: - on fork ->mmap,mm_rb,vmacache_seqnum,map_count,mm_cpumask,locked_vm are zeroed in dup_mmap(); - on fork ->pmd_huge_pte is zeroed in dup_mm(), immediately before calling mm_init(); - ->cpu_vm_mask_var ptr is initialized by mm_init_cpumask(), which is called before mm_init() on both fork and exec; - ->context is initialized by init_new_context(), which is called after mm_init() on both fork and exec; Let's consolidate all the initializations in mm_init() to make the code look cleaner.
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| @@ -374,12 +374,6 @@ static int dup_mmap(struct mm_struct *mm, struct mm_struct *oldmm) · 373 unmodified lines | ||
| 374 | 374 | */ |
| 375 | 375 | down_write_nested(&mm->mmap_sem, SINGLE_DEPTH_NESTING); |
| 376 | 376 | |
| 377 | − mm->locked_vm = 0; | |
| 378 | − mm->mmap = NULL; | |
| 379 | − mm->vmacache_seqnum = 0; | |
| 380 | − mm->map_count = 0; | |
| 381 | − cpumask_clear(mm_cpumask(mm)); | |
| 382 | − mm->mm_rb = RB_ROOT; | |
| 383 | 377 | rb_link = &mm->mm_rb.rb_node; |
| 384 | 378 | rb_parent = NULL; |
| 385 | 379 | pprev = &mm->mmap; |
| @@ -538,17 +532,27 @@ static void mm_init_aio(struct mm_struct *mm) · 152 unmodified lines | ||
| 538 | 532 | |
| 539 | 533 | static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p) |
| 540 | 534 | { |
| 535 | + mm->mmap = NULL; | |
| 536 | + mm->mm_rb = RB_ROOT; | |
| 537 | + mm->vmacache_seqnum = 0; | |
| 541 | 538 | atomic_set(&mm->mm_users, 1); |
| 542 | 539 | atomic_set(&mm->mm_count, 1); |
| 543 | 540 | init_rwsem(&mm->mmap_sem); |
| 544 | 541 | INIT_LIST_HEAD(&mm->mmlist); |
| 545 | 542 | mm->core_state = NULL; |
| 546 | 543 | atomic_long_set(&mm->nr_ptes, 0); |
| 544 | + mm->map_count = 0; | |
| 545 | + mm->locked_vm = 0; | |
| 547 | 546 | memset(&mm->rss_stat, 0, sizeof(mm->rss_stat)); |
| 548 | 547 | spin_lock_init(&mm->page_table_lock); |
| 548 | + mm_init_cpumask(mm); | |
| 549 | 549 | mm_init_aio(mm); |
| 550 | 550 | mm_init_owner(mm, p); |
| 551 | + mmu_notifier_mm_init(mm); | |
| 551 | 552 | clear_tlb_flush_pending(mm); |
| 553 | +#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS | |
| 554 | + mm->pmd_huge_pte = NULL; | |
| 555 | +#endif | |
| 552 | 556 | |
| 553 | 557 | if (current->mm) { |
| 554 | 558 | mm->flags = current->mm->flags & MMF_INIT_MASK; |
| @@ -558,11 +562,17 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p) · 3 unmodified lines | ||
| 558 | 562 | mm->def_flags = 0; |
| 559 | 563 | } |
| 560 | 564 | |
| 561 | − if (likely(!mm_alloc_pgd(mm))) { | |
| 562 | − mmu_notifier_mm_init(mm); | |
| 563 | − return mm; | |
| 564 | − } | |
| 565 | + if (mm_alloc_pgd(mm)) | |
| 566 | + goto fail_nopgd; | |
| 567 | + | |
| 568 | + if (init_new_context(p, mm)) | |
| 569 | + goto fail_nocontext; | |
| 565 | 570 | |
| 571 | + return mm; | |
| 572 | + | |
| 573 | +fail_nocontext: | |
| 574 | + mm_free_pgd(mm); | |
| 575 | +fail_nopgd: | |
| 566 | 576 | free_mm(mm); |
| 567 | 577 | return NULL; |
| 568 | 578 | } |
| @@ -596,7 +606,6 @@ struct mm_struct *mm_alloc(void) · 27 unmodified lines | ||
| 596 | 606 | return NULL; |
| 597 | 607 | |
| 598 | 608 | memset(mm, 0, sizeof(*mm)); |
| 599 | − mm_init_cpumask(mm); | |
| 600 | 609 | return mm_init(mm, current); |
| 601 | 610 | } |
| 602 | 611 | |
| @@ -828,17 +837,10 @@ static struct mm_struct *dup_mm(struct task_struct *tsk) · 225 unmodified lines | ||
| 828 | 837 | goto fail_nomem; |
| 829 | 838 | |
| 830 | 839 | memcpy(mm, oldmm, sizeof(*mm)); |
| 831 | − mm_init_cpumask(mm); | |
| 832 | 840 | |
| 833 | −#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && !USE_SPLIT_PMD_PTLOCKS | |
| 834 | − mm->pmd_huge_pte = NULL; | |
| 835 | −#endif | |
| 836 | 841 | if (!mm_init(mm, tsk)) |
| 837 | 842 | goto fail_nomem; |
| 838 | 843 | |
| 839 | − if (init_new_context(tsk, mm)) | |
| 840 | − goto fail_nocontext; | |
| 841 | − | |
| 842 | 844 | dup_mm_exe_file(oldmm, mm); |
| 843 | 845 | |
| 844 | 846 | err = dup_mmap(mm, oldmm); |
| @@ -860,15 +862,6 @@ free_pt: · 15 unmodified lines | ||
| 860 | 862 | |
| 861 | 863 | fail_nomem: |
| 862 | 864 | return NULL; |
| 863 | − | |
| 864 | −fail_nocontext: | |
| 865 | − /* | |
| 866 | − * If init_new_context() failed, we cannot use mmput() to free the mm | |
| 867 | − * because it calls destroy_context() | |
| 868 | − */ | |
| 869 | − mm_free_pgd(mm); | |
| 870 | − free_mm(mm); | |
| 871 | − return NULL; | |
| 872 | 865 | } |
| 873 | 866 | |
| 874 | 867 | static int copy_mm(unsigned long clone_flags, struct task_struct *tsk) |