linux-2.6.33/mmap_region() の履歴(No.1)

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linux-2.6.33/mmap_region() へ行く。
- 1 (2011-10-31 (月) 18:18:54)

参照元†

linux-2.6.33/do_mmap_pgoff()

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説明†

パス: linux-2.6.33/mm/mmap.c

FIXME: これは何？
- 説明

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引数†

struct file *file
- linux-2.6.33/file unsigned long addr unsigned long len unsigned long flags unsigned int vm_flags unsigned long pgoff

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返り値†

long

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参考†

↑

実装†

unsigned long mmap_region(struct file *file, unsigned long addr,
			  unsigned long len, unsigned long flags,
			  unsigned int vm_flags, unsigned long pgoff)
{
	struct mm_struct *mm = current->mm;
	struct vm_area_struct *vma, *prev;
	int correct_wcount = 0;
	int error;
	struct rb_node **rb_link, *rb_parent;
	unsigned long charged = 0;
	struct inode *inode =  file ? file->f_path.dentry->d_inode : NULL;

	/* Clear old maps */
	error = -ENOMEM;

- linux-2.6.33/ENOMEM

munmap_back:
	vma = find_vma_prepare(mm, addr, &prev, &rb_link, &rb_parent);
	if (vma && vma->vm_start < addr + len) {
		if (do_munmap(mm, addr, len))
			return -ENOMEM;
		goto munmap_back;
	}

- linux-2.6.33/find_vma_prepare()
- linux-2.6.33/do_munmap()

	/* Check against address space limit. */
	if (!may_expand_vm(mm, len >> PAGE_SHIFT))
		return -ENOMEM;

- linux-2.6.33/may_expand_vm()
- linux-2.6.33/PAGE_SHIFT

	/*
	 * Set 'VM_NORESERVE' if we should not account for the
	 * memory use of this mapping.
	 */
	if ((flags & MAP_NORESERVE)) {
		/* We honor MAP_NORESERVE if allowed to overcommit */
		if (sysctl_overcommit_memory != OVERCOMMIT_NEVER)
			vm_flags |= VM_NORESERVE;

		/* hugetlb applies strict overcommit unless MAP_NORESERVE */
		if (file && is_file_hugepages(file))
			vm_flags |= VM_NORESERVE;
	}

	/*
	 * Private writable mapping: check memory availability
	 */
	if (accountable_mapping(file, vm_flags)) {
		charged = len >> PAGE_SHIFT;
		if (security_vm_enough_memory(charged))
			return -ENOMEM;
		vm_flags |= VM_ACCOUNT;
	}

	/*
	 * Can we just expand an old mapping?
	 */
	vma = vma_merge(mm, prev, addr, addr + len, vm_flags, NULL, file, pgoff, NULL);
	if (vma)
		goto out;

- linux-2.6.33/vma_merge()

	/*
	 * Determine the object being mapped and call the appropriate
	 * specific mapper. the address has already been validated, but
	 * not unmapped, but the maps are removed from the list.
	 */
	vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
	if (!vma) {
		error = -ENOMEM;
		goto unacct_error;
	}

	vma->vm_mm = mm;
	vma->vm_start = addr;
	vma->vm_end = addr + len;
	vma->vm_flags = vm_flags;
	vma->vm_page_prot = vm_get_page_prot(vm_flags);
	vma->vm_pgoff = pgoff;

- linux-2.6.33/vm_get_page_prot()

	if (file) {
		error = -EINVAL;
		if (vm_flags & (VM_GROWSDOWN|VM_GROWSUP))
			goto free_vma;
		if (vm_flags & VM_DENYWRITE) {
			error = deny_write_access(file);
			if (error)
				goto free_vma;
			correct_wcount = 1;
		}

		vma->vm_file = file;
		get_file(file);
		error = file->f_op->mmap(file, vma);
		if (error)
			goto unmap_and_free_vma;
		if (vm_flags & VM_EXECUTABLE)
			added_exe_file_vma(mm);

		/* Can addr have changed??
		 *
		 * Answer: Yes, several device drivers can do it in their
		 *         f_op->mmap method. -DaveM
		 */
		addr = vma->vm_start;
		pgoff = vma->vm_pgoff;
		vm_flags = vma->vm_flags;
	} else if (vm_flags & VM_SHARED) {
		error = shmem_zero_setup(vma);
		if (error)
			goto free_vma;

- linux-2.6.33/VM_SHARED
- linux-2.6.33/shmem_zero_setup()

	}

	if (vma_wants_writenotify(vma)) {
		pgprot_t pprot = vma->vm_page_prot;

		/* Can vma->vm_page_prot have changed??
		 *
		 * Answer: Yes, drivers may have changed it in their
		 *         f_op->mmap method.
		 *
		 * Ensures that vmas marked as uncached stay that way.
		 */
		vma->vm_page_prot = vm_get_page_prot(vm_flags & ~VM_SHARED);
		if (pgprot_val(pprot) == pgprot_val(pgprot_noncached(pprot)))
			vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

	}

	vma_link(mm, vma, prev, rb_link, rb_parent);
	file = vma->vm_file;

- linux-2.6.33/vma_link()

	/* Once vma denies write, undo our temporary denial count */
	if (correct_wcount)
		atomic_inc(&inode->i_writecount);

- linux-2.6.33/atomic_inc()

out:
	perf_event_mmap(vma);

- linux-2.6.33/perf_event_mmap()

	mm->total_vm += len >> PAGE_SHIFT;
	vm_stat_account(mm, vm_flags, file, len >> PAGE_SHIFT);

- linux-2.6.33/vm_stat_account()

	if (vm_flags & VM_LOCKED) {
		/*
		 * makes pages present; downgrades, drops, reacquires mmap_sem
		 */
		long nr_pages = mlock_vma_pages_range(vma, addr, addr + len);
		if (nr_pages < 0)
			return nr_pages;	/* vma gone! */
		mm->locked_vm += (len >> PAGE_SHIFT) - nr_pages;
	} else if ((flags & MAP_POPULATE) && !(flags & MAP_NONBLOCK))
		make_pages_present(addr, addr + len);
	return addr;

unmap_and_free_vma:
	if (correct_wcount)
		atomic_inc(&inode->i_writecount);
	vma->vm_file = NULL;
	fput(file);

- linux-2.6.33/fput()

	/* Undo any partial mapping done by a device driver. */
	unmap_region(mm, vma, prev, vma->vm_start, vma->vm_end);
	charged = 0;

- linux-2.6.33/unmap_region()

free_vma:
	kmem_cache_free(vm_area_cachep, vma);

- linux-2.6.33/kmem_cache_free()

unacct_error:
	if (charged)
		vm_unacct_memory(charged);
	return error;

- linux-2.6.33/vm_unacct_memory()

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linux-2.6.33/mmap_region() の履歴(No.1)

参照元†

説明†

引数†

返り値†

参考†

実装†

コメント†