[09/14] bdi: remove BDI_CAP_CGROUP_WRITEBACK
diff mbox series

Message ID 20200722062552.212200-10-hch@lst.de
State New
Headers show
Series
  • [01/14] fs: remove the unused SB_I_MULTIROOT flag
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Commit Message

Christoph Hellwig July 22, 2020, 6:25 a.m. UTC
Just checking SB_I_CGROUPWB for cgroup writeback support is enough.
Either the file system allocates its own bdi (e.g. btrfs), in which case
it is know to support cgroup writeback, or the bdi comes from the block
layer, which always supports cgroup writeback.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 block/blk-core.c            | 1 -
 fs/btrfs/disk-io.c          | 1 -
 include/linux/backing-dev.h | 8 +++-----
 3 files changed, 3 insertions(+), 7 deletions(-)

Comments

Johannes Thumshirn July 22, 2020, 7:45 a.m. UTC | #1
On 22/07/2020 08:27, Christoph Hellwig wrote:
> it is know to support cgroup writeback, or the bdi comes from the block
knwon  ~^

Apart from that,
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
antlists July 26, 2020, 9:01 a.m. UTC | #2
On 22/07/20 08:45, Johannes Thumshirn wrote:
> On 22/07/2020 08:27, Christoph Hellwig wrote:
>> it is know to support cgroup writeback, or the bdi comes from the block
> knwon  ~^
> 
Whoops - "known"

> Apart from that,
> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
> 
Cheers,
Wol

Patch
diff mbox series

diff --git a/block/blk-core.c b/block/blk-core.c
index ea1665de7a2079..68db7e745b49dd 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -538,7 +538,6 @@  struct request_queue *blk_alloc_queue(int node_id)
 	if (!q->stats)
 		goto fail_stats;
 
-	q->backing_dev_info->capabilities = BDI_CAP_CGROUP_WRITEBACK;
 	q->node = node_id;
 
 	timer_setup(&q->backing_dev_info->laptop_mode_wb_timer,
diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index f92c45fe019c48..4b5a8640329e4c 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -3032,7 +3032,6 @@  int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
 		goto fail_sb_buffer;
 	}
 
-	sb->s_bdi->capabilities |= BDI_CAP_CGROUP_WRITEBACK;
 	sb->s_bdi->ra_pages *= btrfs_super_num_devices(disk_super);
 	sb->s_bdi->ra_pages = max(sb->s_bdi->ra_pages, SZ_4M / PAGE_SIZE);
 
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 0b06b2d26c9aa3..52583b6f2ea05d 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -123,7 +123,6 @@  int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned int max_ratio);
  * BDI_CAP_NO_ACCT_WB:     Don't automatically account writeback pages
  * BDI_CAP_STRICTLIMIT:    Keep number of dirty pages below bdi threshold.
  *
- * BDI_CAP_CGROUP_WRITEBACK: Supports cgroup-aware writeback.
  * BDI_CAP_SYNCHRONOUS_IO: Device is so fast that asynchronous IO would be
  *			   inefficient.
  */
@@ -233,9 +232,9 @@  int inode_congested(struct inode *inode, int cong_bits);
  * inode_cgwb_enabled - test whether cgroup writeback is enabled on an inode
  * @inode: inode of interest
  *
- * cgroup writeback requires support from both the bdi and filesystem.
- * Also, both memcg and iocg have to be on the default hierarchy.  Test
- * whether all conditions are met.
+ * Cgroup writeback requires support from the filesystem.  Also, both memcg and
+ * iocg have to be on the default hierarchy.  Test whether all conditions are
+ * met.
  *
  * Note that the test result may change dynamically on the same inode
  * depending on how memcg and iocg are configured.
@@ -247,7 +246,6 @@  static inline bool inode_cgwb_enabled(struct inode *inode)
 	return cgroup_subsys_on_dfl(memory_cgrp_subsys) &&
 		cgroup_subsys_on_dfl(io_cgrp_subsys) &&
 		bdi_cap_account_dirty(bdi) &&
-		(bdi->capabilities & BDI_CAP_CGROUP_WRITEBACK) &&
 		(inode->i_sb->s_iflags & SB_I_CGROUPWB);
 }