writeback: explain why @inode is allowed to be NULL for inode_congested()

Signed-off-by: Tejun Heo <tj@kernel.org>
Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Tejun Heo 2015-08-18 14:54:54 -07:00 committed by Jens Axboe
parent 8a1270cda7
commit 60292bcc1b
1 changed files with 4 additions and 1 deletions

View File

@ -701,7 +701,7 @@ EXPORT_SYMBOL_GPL(wbc_account_io);
/**
* 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
@ -711,6 +711,9 @@ EXPORT_SYMBOL_GPL(wbc_account_io);
* 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)
{