Re: [PATCH block/for-4.3] writeback: explain why @inode is allowed to be NULL for inode_congested()

[Jan Kara]

On Sat 04-07-15 11:12:00, Tejun Heo wrote:
> Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
> Suggested-by: Jan Kara <jack@xxxxxxx>
> ---
> Hello,
> 
> So, something like this.  I'll resend this patch as part of a patch
> series once -rc1 drops.
  Looks good. Thanks!

								Honza

>  fs/fs-writeback.c |    5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
> 
> --- a/fs/fs-writeback.c
> +++ b/fs/fs-writeback.c
> @@ -700,7 +700,7 @@ void wbc_account_io(struct writeback_con
>  
>  /**
>   * inode_congested - test whether an inode is congested
> - * @inode: inode to test for congestion
> + * @inode: inode to test for congestion (may be NULL)
>   * @cong_bits: mask of WB_[a]sync_congested bits to test
>   *
>   * Tests whether @inode is congested.  @cong_bits is the mask of congestion
> @@ -710,6 +710,9 @@ void wbc_account_io(struct writeback_con
>   * determined by whether the cgwb (cgroup bdi_writeback) for the blkcg
>   * associated with @inode is congested; otherwise, the root wb's congestion
>   * state is used.
> + *
> + * @inode is allowed to be NULL as this function is often called on
> + * mapping->host which is NULL for the swapper space.
>   */
>  int inode_congested(struct inode *inode, int cong_bits)
>  {
-- 
Jan Kara <jack@xxxxxxx>
SUSE Labs, CR
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