Messages in this thread Patch in this message | | | Date | Sat, 16 Nov 2002 23:17:18 +0100 | From | Christoph Hellwig <> | Subject | [PATCH] fork.c bits for uClinux |
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mmuless ports don't need dup_mmap nor allocation of a pgd.
I tried to avoid ifdef-mess as far as possible, and to archive that I created small wrappers for pgd allocation/freeing and move taking of the mmap semaphore into dup_mmap from the only caller. The end result is just one additiona ifdef.
--- 1.83/kernel/fork.c Tue Nov 5 23:27:16 2002 +++ edited/kernel/fork.c Thu Nov 14 00:53:05 2002 @@ -205,12 +205,14 @@ return tsk; } +#ifdef CONFIG_MMU static inline int dup_mmap(struct mm_struct * mm) { struct vm_area_struct * mpnt, *tmp, **pprev; int retval; unsigned long charge = 0; + down_write(&mm->mmap_sem); flush_cache_mm(current->mm); mm->locked_vm = 0; mm->mmap = NULL; @@ -287,11 +289,29 @@ out: flush_tlb_mm(current->mm); + up_write(&mm->mmap_sem); return retval; fail_nomem: vm_unacct_memory(charge); goto out; } +static inline int mm_alloc_pgd(struct mm_struct * mm) +{ + mm->pgd = pgd_alloc(mm); + if (unlikely(!mm->pgd)) + return -ENOMEM; + return 0; +} + +static inline void mm_free_pgd(struct mm_struct * mm) +{ + pgd_free(mm->pgd); +} +#else +#define dup_mmap(mm) (0) +#define mm_alloc_pgd(mm) (0) +#define mm_free_pgd(mm) +#endif /* CONFIG_MMU */ spinlock_t mmlist_lock __cacheline_aligned_in_smp = SPIN_LOCK_UNLOCKED; int mmlist_nr; @@ -314,8 +334,7 @@ mm->default_kioctx = (struct kioctx)INIT_KIOCTX(mm->default_kioctx, *mm); mm->free_area_cache = TASK_UNMAPPED_BASE; - mm->pgd = pgd_alloc(mm); - if (mm->pgd) + if (likely(!mm_alloc_pgd(mm))) return mm; free_mm(mm); return NULL; @@ -344,8 +363,8 @@ */ inline void __mmdrop(struct mm_struct *mm) { - if (mm == &init_mm) BUG(); - pgd_free(mm->pgd); + BUG_ON(mm == &init_mm); + mm_free_pgd(mm); destroy_context(mm); free_mm(mm); } @@ -444,10 +463,7 @@ if (init_new_context(tsk,mm)) goto free_pt; - down_write(&oldmm->mmap_sem); retval = dup_mmap(mm); - up_write(&oldmm->mmap_sem); - if (retval) goto free_pt; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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