linux-4.4.1/sys_msync() の変更点

• 追加された行はこの色です。
• 削除された行はこの色です。
• linux-4.4.1/sys_msync() へ行く。
• linux-4.4.1/sys_msync() の差分を削除

*参照元 [#ld99d2fc]
#backlinks

*説明 [#c23487c0]
-パス: [[linux-4.4.1/mm/msync.c]]

-FIXME: これは何？
--説明


**引数 [#t023f75e]
-unsigned long start
--
-size_t len
--
-int flags
--


**返り値 [#ed21c7eb]
-int
--


**参考 [#f68a0328]


*実装 [#s9fa4879]
 /*
  * MS_SYNC syncs the entire file - including mappings.
  *
  * MS_ASYNC does not start I/O (it used to, up to 2.5.67).
  * Nor does it marks the relevant pages dirty (it used to up to 2.6.17).
  * Now it doesn't do anything, since dirty pages are properly tracked.
  *
  * The application may now run fsync() to
  * write out the dirty pages and wait on the writeout and check the result.
  * Or the application may run fadvise(FADV_DONTNEED) against the fd to start
  * async writeout immediately.
  * So by _not_ starting I/O in MS_ASYNC we provide complete flexibility to
  * applications.
  */
 SYSCALL_DEFINE3(msync, unsigned long, start, size_t, len, int, flags)
 {
 	unsigned long end;
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
 	int unmapped_error = 0;
 	int error = -EINVAL;
 
-
--[[linux-4.4.1/mm_struct]]
--[[linux-4.4.1/current(global)]]
--[[linux-4.4.1/vm_area_struct]]

 	if (flags & ~(MS_ASYNC | MS_INVALIDATE | MS_SYNC))
 		goto out;
 	if (offset_in_page(start))
 		goto out;
 	if ((flags & MS_ASYNC) && (flags & MS_SYNC))
 		goto out;
-
--[[linux-4.4.1/offset_in_page()]]

 	error = -ENOMEM;
 	len = (len + ~PAGE_MASK) & PAGE_MASK;
 	end = start + len;
 	if (end < start)
 		goto out;
 	error = 0;
 	if (end == start)
 		goto out;
 	/*
 	 * If the interval [start,end) covers some unmapped address ranges,
 	 * just ignore them, but return -ENOMEM at the end.
 	 */
 	down_read(&mm->mmap_sem);
-
--[[linux-4.4.1/down_read()]]

 	vma = find_vma(mm, start);
-
--[[linux-4.4.1/find_vma()]]

 	for (;;) {
 		struct file *file;
 		loff_t fstart, fend;
 
-
--[[linux-4.4.1/file]]

 		/* Still start < end. */
 		error = -ENOMEM;
 		if (!vma)
 			goto out_unlock;
 		/* Here start < vma->vm_end. */
 		if (start < vma->vm_start) {
 			start = vma->vm_start;
 			if (start >= end)
 				goto out_unlock;
 			unmapped_error = -ENOMEM;
 		}
 		/* Here vma->vm_start <= start < vma->vm_end. */
 		if ((flags & MS_INVALIDATE) &&
 				(vma->vm_flags & VM_LOCKED)) {
 			error = -EBUSY;
 			goto out_unlock;
 		}
 		file = vma->vm_file;
 		fstart = (start - vma->vm_start) +
 			 ((loff_t)vma->vm_pgoff << PAGE_SHIFT);
 		fend = fstart + (min(end, vma->vm_end) - start) - 1;
 		start = vma->vm_end;
 		if ((flags & MS_SYNC) && file &&
 				(vma->vm_flags & VM_SHARED)) {
 			get_file(file);
 			up_read(&mm->mmap_sem);
 			error = vfs_fsync_range(file, fstart, fend, 1);
 			fput(file);
-
--[[linux-4.4.1/get_file()]]
--[[linux-4.4.1/up_read()]]
--[[linux-4.4.1/vfs_fsync_range()]]
--[[linux-4.4.1/fput()]]

 			if (error || start >= end)
 				goto out;
 			down_read(&mm->mmap_sem);
 			vma = find_vma(mm, start);
 		} else {
 			if (start >= end) {
 				error = 0;
 				goto out_unlock;
 			}
 			vma = vma->vm_next;
 		}
 	}
 out_unlock:
 	up_read(&mm->mmap_sem);
 out:
 	return error ? : unmapped_error;
 }


*コメント [#g78b8dac]