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Commit 048c9374a749a27f16493cea033fa4a8ff492356

Authored by NeilBrown
Committed by Jens Axboe
1 parent a1b49cb7e2
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

block: Enhance new plugging support to support general callbacks 

md/raid requires an unplug callback, but as it does not uses
requests the current code cannot provide one.

So allow arbitrary callbacks to be attached to the blk_plug.

Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

Showing 2 changed files with 26 additions and 1 deletions Side-by-side Diff

... ... @@ -2638,6 +2638,7 @@
2638 2638  
2639 2639 plug->magic = PLUG_MAGIC;
2640 2640 INIT_LIST_HEAD(&plug->list);
  2641 + INIT_LIST_HEAD(&plug->cb_list);
2641 2642 plug->should_sort = 0;
2642 2643  
2643 2644 /*
... ... @@ -2678,6 +2679,24 @@
2678 2679 q->unplugged_fn(q);
2679 2680 }
2680 2681  
  2682 +static void flush_plug_callbacks(struct blk_plug *plug)
  2683 +{
  2684 + LIST_HEAD(callbacks);
  2685 +
  2686 + if (list_empty(&plug->cb_list))
  2687 + return;
  2688 +
  2689 + list_splice_init(&plug->cb_list, &callbacks);
  2690 +
  2691 + while (!list_empty(&callbacks)) {
  2692 + struct blk_plug_cb *cb = list_first_entry(&callbacks,
  2693 + struct blk_plug_cb,
  2694 + list);
  2695 + list_del(&cb->list);
  2696 + cb->callback(cb);
  2697 + }
  2698 +}
  2699 +
2681 2700 void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule)
2682 2701 {
2683 2702 struct request_queue *q;
... ... @@ -2688,6 +2707,7 @@
2688 2707  
2689 2708 BUG_ON(plug->magic != PLUG_MAGIC);
2690 2709  
  2710 + flush_plug_callbacks(plug);
2691 2711 if (list_empty(&plug->list))
2692 2712 return;
2693 2713  
include/linux/blkdev.h
Diff comments   View file @ 048c937
... ... @@ -860,8 +860,13 @@
860 860 struct blk_plug {
861 861 unsigned long magic;
862 862 struct list_head list;
  863 + struct list_head cb_list;
863 864 unsigned int should_sort;
864 865 };
  866 +struct blk_plug_cb {
  867 + struct list_head list;
  868 + void (*callback)(struct blk_plug_cb *);
  869 +};
865 870  
866 871 extern void blk_start_plug(struct blk_plug *);
867 872 extern void blk_finish_plug(struct blk_plug *);
... ... @@ -887,7 +892,7 @@
887 892 {
888 893 struct blk_plug *plug = tsk->plug;
889 894  
890   - return plug && !list_empty(&plug->list);
  895 + return plug && (!list_empty(&plug->list) || !list_empty(&plug->cb_list));
891 896 }
892 897  
893 898 /*