diff options
| author | Shaohua Li <shaohua.li@intel.com> | 2011-07-08 08:19:21 +0200 |
|---|---|---|
| committer | Jens Axboe <jaxboe@fusionio.com> | 2011-07-08 08:19:21 +0200 |
| commit | 316cc67d5e03801a5ee4ac660a4dfe9e02aed475 (patch) | |
| tree | ddcac370cf4402127a9609cfe6bb86eb1ebb6c8d /include | |
| parent | 55c022bbddb2c056b5dff1bd1b1758d31b6d64c9 (diff) | |
block: document blk_plug list access
I'm often confused why not disable preempt when changing blk_plug list. It
would be better to add comments here in case others have the similar concerns.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/blkdev.h | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index 92edb9601242..6dcea6885a5d 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -857,6 +857,12 @@ struct request_queue *blk_alloc_queue(gfp_t); struct request_queue *blk_alloc_queue_node(gfp_t, int); extern void blk_put_queue(struct request_queue *); +/* + * Note: Code in between changing the blk_plug list/cb_list or element of such + * lists is preemptable, but such code can't do sleep (or be very careful), + * otherwise data is corrupted. For details, please check schedule() where + * blk_schedule_flush_plug() is called. + */ struct blk_plug { unsigned long magic; struct list_head list; |