2020-07-01 09:07:04

by Christoph Hellwig

[permalink] [raw]
Subject: remove dead bdi congestion leftovers

Hi Jens,

we have a lot of bdi congestion related code that is left around without
any use. This series removes it in preparation of sorting out the bdi
lifetime rules properly.

Diffstat:
block/blk-cgroup.c | 19 ----
drivers/block/drbd/drbd_main.c | 59 --------------
drivers/block/drbd/drbd_proc.c | 1
drivers/md/bcache/request.c | 43 ----------
drivers/md/bcache/super.c | 1
drivers/md/dm-cache-target.c | 19 ----
drivers/md/dm-clone-target.c | 15 ---
drivers/md/dm-era-target.c | 15 ---
drivers/md/dm-raid.c | 12 --
drivers/md/dm-table.c | 37 ---------
drivers/md/dm-thin.c | 16 ---
drivers/md/dm.c | 33 --------
drivers/md/dm.h | 1
drivers/md/md-linear.c | 24 -----
drivers/md/md-multipath.c | 23 -----
drivers/md/md.c | 23 -----
drivers/md/md.h | 4
drivers/md/raid0.c | 16 ---
drivers/md/raid1.c | 31 -------
drivers/md/raid10.c | 26 ------
drivers/md/raid5.c | 25 ------
fs/btrfs/disk-io.c | 23 -----
include/linux/backing-dev-defs.h | 43 ----------
include/linux/backing-dev.h | 22 -----
include/linux/blk-cgroup.h | 6 -
include/linux/device-mapper.h | 11 --
mm/backing-dev.c | 157 +++------------------------------------
27 files changed, 20 insertions(+), 685 deletions(-)


2020-07-01 09:07:16

by Christoph Hellwig

[permalink] [raw]
Subject: [PATCH 3/4] writeback: remove struct bdi_writeback_congested

We never set any congested bits in the group writeback instances of it.
And for the simpler bdi-wide case a simple scalar field is all that
that is needed.

Signed-off-by: Christoph Hellwig <[email protected]>
---
block/blk-cgroup.c | 19 +---
drivers/md/dm.c | 2 +-
include/linux/backing-dev-defs.h | 25 +-----
include/linux/backing-dev.h | 18 +---
include/linux/blk-cgroup.h | 6 --
mm/backing-dev.c | 149 ++-----------------------------
6 files changed, 14 insertions(+), 205 deletions(-)

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 1ce94afc03bcfd..30dc14ddf0f69c 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -95,9 +95,6 @@ static void __blkg_release(struct rcu_head *rcu)
css_put(&blkg->blkcg->css);
if (blkg->parent)
blkg_put(blkg->parent);
-
- wb_congested_put(blkg->wb_congested);
-
blkg_free(blkg);
}

@@ -227,7 +224,6 @@ static struct blkcg_gq *blkg_create(struct blkcg *blkcg,
struct blkcg_gq *new_blkg)
{
struct blkcg_gq *blkg;
- struct bdi_writeback_congested *wb_congested;
int i, ret;

WARN_ON_ONCE(!rcu_read_lock_held());
@@ -245,31 +241,22 @@ static struct blkcg_gq *blkg_create(struct blkcg *blkcg,
goto err_free_blkg;
}

- wb_congested = wb_congested_get_create(q->backing_dev_info,
- blkcg->css.id,
- GFP_NOWAIT | __GFP_NOWARN);
- if (!wb_congested) {
- ret = -ENOMEM;
- goto err_put_css;
- }
-
/* allocate */
if (!new_blkg) {
new_blkg = blkg_alloc(blkcg, q, GFP_NOWAIT | __GFP_NOWARN);
if (unlikely(!new_blkg)) {
ret = -ENOMEM;
- goto err_put_congested;
+ goto err_put_css;
}
}
blkg = new_blkg;
- blkg->wb_congested = wb_congested;

/* link parent */
if (blkcg_parent(blkcg)) {
blkg->parent = __blkg_lookup(blkcg_parent(blkcg), q, false);
if (WARN_ON_ONCE(!blkg->parent)) {
ret = -ENODEV;
- goto err_put_congested;
+ goto err_put_css;
}
blkg_get(blkg->parent);
}
@@ -306,8 +293,6 @@ static struct blkcg_gq *blkg_create(struct blkcg *blkcg,
blkg_put(blkg);
return ERR_PTR(ret);

-err_put_congested:
- wb_congested_put(wb_congested);
err_put_css:
css_put(&blkcg->css);
err_free_blkg:
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index e44473fe0f4873..97838b6d0b5473 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1838,7 +1838,7 @@ static int dm_any_congested(void *congested_data, int bdi_bits)
* top-level queue for congestion.
*/
struct backing_dev_info *bdi = md->queue->backing_dev_info;
- r = bdi->wb.congested->state & bdi_bits;
+ r = bdi->wb.congested & bdi_bits;
} else {
map = dm_get_live_table_fast(md);
if (map)
diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h
index cc5aa1f32b91f0..1cec4521e1fbe2 100644
--- a/include/linux/backing-dev-defs.h
+++ b/include/linux/backing-dev-defs.h
@@ -87,26 +87,6 @@ struct wb_completion {
#define DEFINE_WB_COMPLETION(cmpl, bdi) \
struct wb_completion cmpl = WB_COMPLETION_INIT(bdi)

-/*
- * For cgroup writeback, multiple wb's may map to the same blkcg. Those
- * wb's can operate mostly independently but should share the congested
- * state. To facilitate such sharing, the congested state is tracked using
- * the following struct which is created on demand, indexed by blkcg ID on
- * its bdi, and refcounted.
- */
-struct bdi_writeback_congested {
- unsigned long state; /* WB_[a]sync_congested flags */
- refcount_t refcnt; /* nr of attached wb's and blkg */
-
-#ifdef CONFIG_CGROUP_WRITEBACK
- struct backing_dev_info *__bdi; /* the associated bdi, set to NULL
- * on bdi unregistration. For memcg-wb
- * internal use only! */
- int blkcg_id; /* ID of the associated blkcg */
- struct rb_node rb_node; /* on bdi->cgwb_congestion_tree */
-#endif
-};
-
/*
* Each wb (bdi_writeback) can perform writeback operations, is measured
* and throttled, independently. Without cgroup writeback, each bdi
@@ -140,7 +120,7 @@ struct bdi_writeback {

struct percpu_counter stat[NR_WB_STAT_ITEMS];

- struct bdi_writeback_congested *congested;
+ unsigned long congested; /* WB_[a]sync_congested flags */

unsigned long bw_time_stamp; /* last time write bw is updated */
unsigned long dirtied_stamp;
@@ -208,11 +188,8 @@ struct backing_dev_info {
struct list_head wb_list; /* list of all wbs */
#ifdef CONFIG_CGROUP_WRITEBACK
struct radix_tree_root cgwb_tree; /* radix tree of active cgroup wbs */
- struct rb_root cgwb_congested_tree; /* their congested states */
struct mutex cgwb_release_mutex; /* protect shutdown of wb structs */
struct rw_semaphore wb_switch_rwsem; /* no cgwb switch while syncing */
-#else
- struct bdi_writeback_congested *wb_congested;
#endif
wait_queue_head_t wb_waitq;

diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 6b3504bf7a42b3..9173d2c22b4aa0 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -173,7 +173,7 @@ static inline int wb_congested(struct bdi_writeback *wb, int cong_bits)

if (bdi->congested_fn)
return bdi->congested_fn(bdi->congested_data, cong_bits);
- return wb->congested->state & cong_bits;
+ return wb->congested & cong_bits;
}

long congestion_wait(int sync, long timeout);
@@ -224,9 +224,6 @@ static inline int bdi_sched_wait(void *word)

#ifdef CONFIG_CGROUP_WRITEBACK

-struct bdi_writeback_congested *
-wb_congested_get_create(struct backing_dev_info *bdi, int blkcg_id, gfp_t gfp);
-void wb_congested_put(struct bdi_writeback_congested *congested);
struct bdi_writeback *wb_get_lookup(struct backing_dev_info *bdi,
struct cgroup_subsys_state *memcg_css);
struct bdi_writeback *wb_get_create(struct backing_dev_info *bdi,
@@ -404,19 +401,6 @@ static inline bool inode_cgwb_enabled(struct inode *inode)
return false;
}

-static inline struct bdi_writeback_congested *
-wb_congested_get_create(struct backing_dev_info *bdi, int blkcg_id, gfp_t gfp)
-{
- refcount_inc(&bdi->wb_congested->refcnt);
- return bdi->wb_congested;
-}
-
-static inline void wb_congested_put(struct bdi_writeback_congested *congested)
-{
- if (refcount_dec_and_test(&congested->refcnt))
- kfree(congested);
-}
-
static inline struct bdi_writeback *wb_find_current(struct backing_dev_info *bdi)
{
return &bdi->wb;
diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h
index 431b2d18bf4074..c8fc9792ac776d 100644
--- a/include/linux/blk-cgroup.h
+++ b/include/linux/blk-cgroup.h
@@ -109,12 +109,6 @@ struct blkcg_gq {
struct hlist_node blkcg_node;
struct blkcg *blkcg;

- /*
- * Each blkg gets congested separately and the congestion state is
- * propagated to the matching bdi_writeback_congested.
- */
- struct bdi_writeback_congested *wb_congested;
-
/* all non-root blkcg_gq's are guaranteed to have access to parent */
struct blkcg_gq *parent;

diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index 3ebe5144a102f2..8e8b00627bb2d8 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -281,7 +281,7 @@ void wb_wakeup_delayed(struct bdi_writeback *wb)
#define INIT_BW (100 << (20 - PAGE_SHIFT))

static int wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi,
- int blkcg_id, gfp_t gfp)
+ gfp_t gfp)
{
int i, err;

@@ -308,15 +308,9 @@ static int wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi,
INIT_DELAYED_WORK(&wb->dwork, wb_workfn);
wb->dirty_sleep = jiffies;

- wb->congested = wb_congested_get_create(bdi, blkcg_id, gfp);
- if (!wb->congested) {
- err = -ENOMEM;
- goto out_put_bdi;
- }
-
err = fprop_local_init_percpu(&wb->completions, gfp);
if (err)
- goto out_put_cong;
+ goto out_put_bdi;

for (i = 0; i < NR_WB_STAT_ITEMS; i++) {
err = percpu_counter_init(&wb->stat[i], 0, gfp);
@@ -330,8 +324,6 @@ static int wb_init(struct bdi_writeback *wb, struct backing_dev_info *bdi,
while (i--)
percpu_counter_destroy(&wb->stat[i]);
fprop_local_destroy_percpu(&wb->completions);
-out_put_cong:
- wb_congested_put(wb->congested);
out_put_bdi:
if (wb != &bdi->wb)
bdi_put(bdi);
@@ -374,7 +366,6 @@ static void wb_exit(struct bdi_writeback *wb)
percpu_counter_destroy(&wb->stat[i]);

fprop_local_destroy_percpu(&wb->completions);
- wb_congested_put(wb->congested);
if (wb != &wb->bdi->wb)
bdi_put(wb->bdi);
}
@@ -384,99 +375,12 @@ static void wb_exit(struct bdi_writeback *wb)
#include <linux/memcontrol.h>

/*
- * cgwb_lock protects bdi->cgwb_tree, bdi->cgwb_congested_tree,
- * blkcg->cgwb_list, and memcg->cgwb_list. bdi->cgwb_tree is also RCU
- * protected.
+ * cgwb_lock protects bdi->cgwb_tree, blkcg->cgwb_list, and memcg->cgwb_list.
+ * bdi->cgwb_tree is also RCU protected.
*/
static DEFINE_SPINLOCK(cgwb_lock);
static struct workqueue_struct *cgwb_release_wq;

-/**
- * wb_congested_get_create - get or create a wb_congested
- * @bdi: associated bdi
- * @blkcg_id: ID of the associated blkcg
- * @gfp: allocation mask
- *
- * Look up the wb_congested for @blkcg_id on @bdi. If missing, create one.
- * The returned wb_congested has its reference count incremented. Returns
- * NULL on failure.
- */
-struct bdi_writeback_congested *
-wb_congested_get_create(struct backing_dev_info *bdi, int blkcg_id, gfp_t gfp)
-{
- struct bdi_writeback_congested *new_congested = NULL, *congested;
- struct rb_node **node, *parent;
- unsigned long flags;
-retry:
- spin_lock_irqsave(&cgwb_lock, flags);
-
- node = &bdi->cgwb_congested_tree.rb_node;
- parent = NULL;
-
- while (*node != NULL) {
- parent = *node;
- congested = rb_entry(parent, struct bdi_writeback_congested,
- rb_node);
- if (congested->blkcg_id < blkcg_id)
- node = &parent->rb_left;
- else if (congested->blkcg_id > blkcg_id)
- node = &parent->rb_right;
- else
- goto found;
- }
-
- if (new_congested) {
- /* !found and storage for new one already allocated, insert */
- congested = new_congested;
- rb_link_node(&congested->rb_node, parent, node);
- rb_insert_color(&congested->rb_node, &bdi->cgwb_congested_tree);
- spin_unlock_irqrestore(&cgwb_lock, flags);
- return congested;
- }
-
- spin_unlock_irqrestore(&cgwb_lock, flags);
-
- /* allocate storage for new one and retry */
- new_congested = kzalloc(sizeof(*new_congested), gfp);
- if (!new_congested)
- return NULL;
-
- refcount_set(&new_congested->refcnt, 1);
- new_congested->__bdi = bdi;
- new_congested->blkcg_id = blkcg_id;
- goto retry;
-
-found:
- refcount_inc(&congested->refcnt);
- spin_unlock_irqrestore(&cgwb_lock, flags);
- kfree(new_congested);
- return congested;
-}
-
-/**
- * wb_congested_put - put a wb_congested
- * @congested: wb_congested to put
- *
- * Put @congested and destroy it if the refcnt reaches zero.
- */
-void wb_congested_put(struct bdi_writeback_congested *congested)
-{
- unsigned long flags;
-
- if (!refcount_dec_and_lock_irqsave(&congested->refcnt, &cgwb_lock, &flags))
- return;
-
- /* bdi might already have been destroyed leaving @congested unlinked */
- if (congested->__bdi) {
- rb_erase(&congested->rb_node,
- &congested->__bdi->cgwb_congested_tree);
- congested->__bdi = NULL;
- }
-
- spin_unlock_irqrestore(&cgwb_lock, flags);
- kfree(congested);
-}
-
static void cgwb_release_workfn(struct work_struct *work)
{
struct bdi_writeback *wb = container_of(work, struct bdi_writeback,
@@ -558,7 +462,7 @@ static int cgwb_create(struct backing_dev_info *bdi,
goto out_put;
}

- ret = wb_init(wb, bdi, blkcg_css->id, gfp);
+ ret = wb_init(wb, bdi, gfp);
if (ret)
goto err_free;

@@ -696,11 +600,10 @@ static int cgwb_bdi_init(struct backing_dev_info *bdi)
int ret;

INIT_RADIX_TREE(&bdi->cgwb_tree, GFP_ATOMIC);
- bdi->cgwb_congested_tree = RB_ROOT;
mutex_init(&bdi->cgwb_release_mutex);
init_rwsem(&bdi->wb_switch_rwsem);

- ret = wb_init(&bdi->wb, bdi, 1, GFP_KERNEL);
+ ret = wb_init(&bdi->wb, bdi, GFP_KERNEL);
if (!ret) {
bdi->wb.memcg_css = &root_mem_cgroup->css;
bdi->wb.blkcg_css = blkcg_root_css;
@@ -769,21 +672,6 @@ void wb_blkcg_offline(struct blkcg *blkcg)
spin_unlock_irq(&cgwb_lock);
}

-static void cgwb_bdi_exit(struct backing_dev_info *bdi)
-{
- struct rb_node *rbn;
-
- spin_lock_irq(&cgwb_lock);
- while ((rbn = rb_first(&bdi->cgwb_congested_tree))) {
- struct bdi_writeback_congested *congested =
- rb_entry(rbn, struct bdi_writeback_congested, rb_node);
-
- rb_erase(rbn, &bdi->cgwb_congested_tree);
- congested->__bdi = NULL; /* mark @congested unlinked */
- }
- spin_unlock_irq(&cgwb_lock);
-}
-
static void cgwb_bdi_register(struct backing_dev_info *bdi)
{
spin_lock_irq(&cgwb_lock);
@@ -810,29 +698,11 @@ subsys_initcall(cgwb_init);

static int cgwb_bdi_init(struct backing_dev_info *bdi)
{
- int err;
-
- bdi->wb_congested = kzalloc(sizeof(*bdi->wb_congested), GFP_KERNEL);
- if (!bdi->wb_congested)
- return -ENOMEM;
-
- refcount_set(&bdi->wb_congested->refcnt, 1);
-
- err = wb_init(&bdi->wb, bdi, 1, GFP_KERNEL);
- if (err) {
- wb_congested_put(bdi->wb_congested);
- return err;
- }
- return 0;
+ return wb_init(&bdi->wb, bdi, GFP_KERNEL);
}

static void cgwb_bdi_unregister(struct backing_dev_info *bdi) { }

-static void cgwb_bdi_exit(struct backing_dev_info *bdi)
-{
- wb_congested_put(bdi->wb_congested);
-}
-
static void cgwb_bdi_register(struct backing_dev_info *bdi)
{
list_add_tail_rcu(&bdi->wb.bdi_node, &bdi->wb_list);
@@ -1023,7 +893,6 @@ static void release_bdi(struct kref *ref)
bdi_unregister(bdi);
WARN_ON_ONCE(bdi->dev);
wb_exit(&bdi->wb);
- cgwb_bdi_exit(bdi);
kfree(bdi);
}

@@ -1053,7 +922,7 @@ void clear_bdi_congested(struct backing_dev_info *bdi, int sync)
enum wb_congested_state bit;

bit = sync ? WB_sync_congested : WB_async_congested;
- if (test_and_clear_bit(bit, &bdi->wb.congested->state))
+ if (test_and_clear_bit(bit, &bdi->wb.congested))
atomic_dec(&nr_wb_congested[sync]);
smp_mb__after_atomic();
if (waitqueue_active(wqh))
@@ -1066,7 +935,7 @@ void set_bdi_congested(struct backing_dev_info *bdi, int sync)
enum wb_congested_state bit;

bit = sync ? WB_sync_congested : WB_async_congested;
- if (!test_and_set_bit(bit, &bdi->wb.congested->state))
+ if (!test_and_set_bit(bit, &bdi->wb.congested))
atomic_inc(&nr_wb_congested[sync]);
}
EXPORT_SYMBOL(set_bdi_congested);
--
2.26.2

2020-07-01 09:07:18

by Christoph Hellwig

[permalink] [raw]
Subject: [PATCH 2/4] writeback: remove {set,clear}_wb_congested

Just merge them into their only callers.

Signed-off-by: Christoph Hellwig <[email protected]>
---
include/linux/backing-dev-defs.h | 14 ++------------
mm/backing-dev.c | 12 ++++++------
2 files changed, 8 insertions(+), 18 deletions(-)

diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h
index 90a7e844a098f3..cc5aa1f32b91f0 100644
--- a/include/linux/backing-dev-defs.h
+++ b/include/linux/backing-dev-defs.h
@@ -232,18 +232,8 @@ enum {
BLK_RW_SYNC = 1,
};

-void clear_wb_congested(struct bdi_writeback_congested *congested, int sync);
-void set_wb_congested(struct bdi_writeback_congested *congested, int sync);
-
-static inline void clear_bdi_congested(struct backing_dev_info *bdi, int sync)
-{
- clear_wb_congested(bdi->wb.congested, sync);
-}
-
-static inline void set_bdi_congested(struct backing_dev_info *bdi, int sync)
-{
- set_wb_congested(bdi->wb.congested, sync);
-}
+void clear_bdi_congested(struct backing_dev_info *bdi, int sync);
+void set_bdi_congested(struct backing_dev_info *bdi, int sync);

struct wb_lock_cookie {
bool locked;
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index d382272bcc3100..3ebe5144a102f2 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -1047,29 +1047,29 @@ static wait_queue_head_t congestion_wqh[2] = {
};
static atomic_t nr_wb_congested[2];

-void clear_wb_congested(struct bdi_writeback_congested *congested, int sync)
+void clear_bdi_congested(struct backing_dev_info *bdi, int sync)
{
wait_queue_head_t *wqh = &congestion_wqh[sync];
enum wb_congested_state bit;

bit = sync ? WB_sync_congested : WB_async_congested;
- if (test_and_clear_bit(bit, &congested->state))
+ if (test_and_clear_bit(bit, &bdi->wb.congested->state))
atomic_dec(&nr_wb_congested[sync]);
smp_mb__after_atomic();
if (waitqueue_active(wqh))
wake_up(wqh);
}
-EXPORT_SYMBOL(clear_wb_congested);
+EXPORT_SYMBOL(clear_bdi_congested);

-void set_wb_congested(struct bdi_writeback_congested *congested, int sync)
+void set_bdi_congested(struct backing_dev_info *bdi, int sync)
{
enum wb_congested_state bit;

bit = sync ? WB_sync_congested : WB_async_congested;
- if (!test_and_set_bit(bit, &congested->state))
+ if (!test_and_set_bit(bit, &bdi->wb.congested->state))
atomic_inc(&nr_wb_congested[sync]);
}
-EXPORT_SYMBOL(set_wb_congested);
+EXPORT_SYMBOL(set_bdi_congested);

/**
* congestion_wait - wait for a backing_dev to become uncongested
--
2.26.2

2020-07-01 09:08:18

by Christoph Hellwig

[permalink] [raw]
Subject: [PATCH 1/4] drbd: remove a bogus bdi_rw_congested call

bdi_rw_congested returns congestion state, so calling it without
looking at the return value doesn't make much sense.

Signed-off-by: Christoph Hellwig <[email protected]>
---
drivers/block/drbd/drbd_proc.c | 1 -
1 file changed, 1 deletion(-)

diff --git a/drivers/block/drbd/drbd_proc.c b/drivers/block/drbd/drbd_proc.c
index 1c41cd9982a257..3c0193de249830 100644
--- a/drivers/block/drbd/drbd_proc.c
+++ b/drivers/block/drbd/drbd_proc.c
@@ -265,7 +265,6 @@ int drbd_seq_show(struct seq_file *seq, void *v)
seq_printf(seq, "%2d: cs:Unconfigured\n", i);
} else {
/* reset device->congestion_reason */
- bdi_rw_congested(device->rq_queue->backing_dev_info);

nc = rcu_dereference(first_peer_device(device)->connection->net_conf);
wp = nc ? nc->wire_protocol - DRBD_PROT_A + 'A' : ' ';
--
2.26.2

2020-07-01 09:09:27

by Christoph Hellwig

[permalink] [raw]
Subject: [PATCH 4/4] writeback: remove bdi->congested_fn

Except for pktdvd, the only places setting congested bits are file
systems that allocate their own backing_dev_info structures. And
pktdvd is a deprecated driver that isn't useful in stack setup
either. So remove the dead congested_fn stacking infrastructure.

Signed-off-by: Christoph Hellwig <[email protected]>
---
drivers/block/drbd/drbd_main.c | 59 --------------------------------
drivers/md/bcache/request.c | 43 -----------------------
drivers/md/bcache/super.c | 1 -
drivers/md/dm-cache-target.c | 19 ----------
drivers/md/dm-clone-target.c | 15 --------
drivers/md/dm-era-target.c | 15 --------
drivers/md/dm-raid.c | 12 -------
drivers/md/dm-table.c | 37 +-------------------
drivers/md/dm-thin.c | 16 ---------
drivers/md/dm.c | 33 ------------------
drivers/md/dm.h | 1 -
drivers/md/md-linear.c | 24 -------------
drivers/md/md-multipath.c | 23 -------------
drivers/md/md.c | 23 -------------
drivers/md/md.h | 4 ---
drivers/md/raid0.c | 16 ---------
drivers/md/raid1.c | 31 -----------------
drivers/md/raid10.c | 26 --------------
drivers/md/raid5.c | 25 --------------
fs/btrfs/disk-io.c | 23 -------------
include/linux/backing-dev-defs.h | 4 ---
include/linux/backing-dev.h | 4 ---
include/linux/device-mapper.h | 11 ------
23 files changed, 1 insertion(+), 464 deletions(-)

diff --git a/drivers/block/drbd/drbd_main.c b/drivers/block/drbd/drbd_main.c
index 45fbd526c453bc..e9c9ac3c520282 100644
--- a/drivers/block/drbd/drbd_main.c
+++ b/drivers/block/drbd/drbd_main.c
@@ -2414,62 +2414,6 @@ static void drbd_cleanup(void)
pr_info("module cleanup done.\n");
}

-/**
- * drbd_congested() - Callback for the flusher thread
- * @congested_data: User data
- * @bdi_bits: Bits the BDI flusher thread is currently interested in
- *
- * Returns 1<<WB_async_congested and/or 1<<WB_sync_congested if we are congested.
- */
-static int drbd_congested(void *congested_data, int bdi_bits)
-{
- struct drbd_device *device = congested_data;
- struct request_queue *q;
- char reason = '-';
- int r = 0;
-
- if (!may_inc_ap_bio(device)) {
- /* DRBD has frozen IO */
- r = bdi_bits;
- reason = 'd';
- goto out;
- }
-
- if (test_bit(CALLBACK_PENDING, &first_peer_device(device)->connection->flags)) {
- r |= (1 << WB_async_congested);
- /* Without good local data, we would need to read from remote,
- * and that would need the worker thread as well, which is
- * currently blocked waiting for that usermode helper to
- * finish.
- */
- if (!get_ldev_if_state(device, D_UP_TO_DATE))
- r |= (1 << WB_sync_congested);
- else
- put_ldev(device);
- r &= bdi_bits;
- reason = 'c';
- goto out;
- }
-
- if (get_ldev(device)) {
- q = bdev_get_queue(device->ldev->backing_bdev);
- r = bdi_congested(q->backing_dev_info, bdi_bits);
- put_ldev(device);
- if (r)
- reason = 'b';
- }
-
- if (bdi_bits & (1 << WB_async_congested) &&
- test_bit(NET_CONGESTED, &first_peer_device(device)->connection->flags)) {
- r |= (1 << WB_async_congested);
- reason = reason == 'b' ? 'a' : 'n';
- }
-
-out:
- device->congestion_reason = reason;
- return r;
-}
-
static void drbd_init_workqueue(struct drbd_work_queue* wq)
{
spin_lock_init(&wq->q_lock);
@@ -2825,9 +2769,6 @@ enum drbd_ret_code drbd_create_device(struct drbd_config_context *adm_ctx, unsig
/* we have no partitions. we contain only ourselves. */
device->this_bdev->bd_contains = device->this_bdev;

- q->backing_dev_info->congested_fn = drbd_congested;
- q->backing_dev_info->congested_data = device;
-
blk_queue_write_cache(q, true, true);
/* Setting the max_hw_sectors to an odd value of 8kibyte here
This triggers a max_bio_size message upon first attach or connect */
diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c
index 7acf024e99f351..cda05fc61c3afa 100644
--- a/drivers/md/bcache/request.c
+++ b/drivers/md/bcache/request.c
@@ -1228,36 +1228,10 @@ static int cached_dev_ioctl(struct bcache_device *d, fmode_t mode,
return __blkdev_driver_ioctl(dc->bdev, mode, cmd, arg);
}

-static int cached_dev_congested(void *data, int bits)
-{
- struct bcache_device *d = data;
- struct cached_dev *dc = container_of(d, struct cached_dev, disk);
- struct request_queue *q = bdev_get_queue(dc->bdev);
- int ret = 0;
-
- if (bdi_congested(q->backing_dev_info, bits))
- return 1;
-
- if (cached_dev_get(dc)) {
- unsigned int i;
- struct cache *ca;
-
- for_each_cache(ca, d->c, i) {
- q = bdev_get_queue(ca->bdev);
- ret |= bdi_congested(q->backing_dev_info, bits);
- }
-
- cached_dev_put(dc);
- }
-
- return ret;
-}
-
void bch_cached_dev_request_init(struct cached_dev *dc)
{
struct gendisk *g = dc->disk.disk;

- g->queue->backing_dev_info->congested_fn = cached_dev_congested;
dc->disk.cache_miss = cached_dev_cache_miss;
dc->disk.ioctl = cached_dev_ioctl;
}
@@ -1342,27 +1316,10 @@ static int flash_dev_ioctl(struct bcache_device *d, fmode_t mode,
return -ENOTTY;
}

-static int flash_dev_congested(void *data, int bits)
-{
- struct bcache_device *d = data;
- struct request_queue *q;
- struct cache *ca;
- unsigned int i;
- int ret = 0;
-
- for_each_cache(ca, d->c, i) {
- q = bdev_get_queue(ca->bdev);
- ret |= bdi_congested(q->backing_dev_info, bits);
- }
-
- return ret;
-}
-
void bch_flash_dev_request_init(struct bcache_device *d)
{
struct gendisk *g = d->disk;

- g->queue->backing_dev_info->congested_fn = flash_dev_congested;
d->cache_miss = flash_dev_cache_miss;
d->ioctl = flash_dev_ioctl;
}
diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
index 2014016f9a60d3..1810d7ca2f6653 100644
--- a/drivers/md/bcache/super.c
+++ b/drivers/md/bcache/super.c
@@ -877,7 +877,6 @@ static int bcache_device_init(struct bcache_device *d, unsigned int block_size,

d->disk->queue = q;
q->queuedata = d;
- q->backing_dev_info->congested_data = d;
q->limits.max_hw_sectors = UINT_MAX;
q->limits.max_sectors = UINT_MAX;
q->limits.max_segment_size = UINT_MAX;
diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index d3bb355819a421..24549dc92eeec5 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -421,8 +421,6 @@ struct cache {

struct rw_semaphore quiesce_lock;

- struct dm_target_callbacks callbacks;
-
/*
* origin_blocks entries, discarded if set.
*/
@@ -2423,20 +2421,6 @@ static void set_cache_size(struct cache *cache, dm_cblock_t size)
cache->cache_size = size;
}

-static int is_congested(struct dm_dev *dev, int bdi_bits)
-{
- struct request_queue *q = bdev_get_queue(dev->bdev);
- return bdi_congested(q->backing_dev_info, bdi_bits);
-}
-
-static int cache_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
-{
- struct cache *cache = container_of(cb, struct cache, callbacks);
-
- return is_congested(cache->origin_dev, bdi_bits) ||
- is_congested(cache->cache_dev, bdi_bits);
-}
-
#define DEFAULT_MIGRATION_THRESHOLD 2048

static int cache_create(struct cache_args *ca, struct cache **result)
@@ -2471,9 +2455,6 @@ static int cache_create(struct cache_args *ca, struct cache **result)
goto bad;
}

- cache->callbacks.congested_fn = cache_is_congested;
- dm_table_add_target_callbacks(ti->table, &cache->callbacks);
-
cache->metadata_dev = ca->metadata_dev;
cache->origin_dev = ca->origin_dev;
cache->cache_dev = ca->cache_dev;
diff --git a/drivers/md/dm-clone-target.c b/drivers/md/dm-clone-target.c
index 5ce96ddf1ce1eb..8e900418d571ff 100644
--- a/drivers/md/dm-clone-target.c
+++ b/drivers/md/dm-clone-target.c
@@ -68,7 +68,6 @@ struct hash_table_bucket;

struct clone {
struct dm_target *ti;
- struct dm_target_callbacks callbacks;

struct dm_dev *metadata_dev;
struct dm_dev *dest_dev;
@@ -1518,18 +1517,6 @@ static void clone_status(struct dm_target *ti, status_type_t type,
DMEMIT("Error");
}

-static int clone_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
-{
- struct request_queue *dest_q, *source_q;
- struct clone *clone = container_of(cb, struct clone, callbacks);
-
- source_q = bdev_get_queue(clone->source_dev->bdev);
- dest_q = bdev_get_queue(clone->dest_dev->bdev);
-
- return (bdi_congested(dest_q->backing_dev_info, bdi_bits) |
- bdi_congested(source_q->backing_dev_info, bdi_bits));
-}
-
static sector_t get_dev_size(struct dm_dev *dev)
{
return i_size_read(dev->bdev->bd_inode) >> SECTOR_SHIFT;
@@ -1930,8 +1917,6 @@ static int clone_ctr(struct dm_target *ti, unsigned int argc, char **argv)
goto out_with_mempool;

mutex_init(&clone->commit_lock);
- clone->callbacks.congested_fn = clone_is_congested;
- dm_table_add_target_callbacks(ti->table, &clone->callbacks);

/* Enable flushes */
ti->num_flush_bios = 1;
diff --git a/drivers/md/dm-era-target.c b/drivers/md/dm-era-target.c
index bdb84b8e71621d..e8d3b5abc85bd6 100644
--- a/drivers/md/dm-era-target.c
+++ b/drivers/md/dm-era-target.c
@@ -1137,7 +1137,6 @@ static int metadata_get_stats(struct era_metadata *md, void *ptr)

struct era {
struct dm_target *ti;
- struct dm_target_callbacks callbacks;

struct dm_dev *metadata_dev;
struct dm_dev *origin_dev;
@@ -1375,18 +1374,6 @@ static void stop_worker(struct era *era)
/*----------------------------------------------------------------
* Target methods
*--------------------------------------------------------------*/
-static int dev_is_congested(struct dm_dev *dev, int bdi_bits)
-{
- struct request_queue *q = bdev_get_queue(dev->bdev);
- return bdi_congested(q->backing_dev_info, bdi_bits);
-}
-
-static int era_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
-{
- struct era *era = container_of(cb, struct era, callbacks);
- return dev_is_congested(era->origin_dev, bdi_bits);
-}
-
static void era_destroy(struct era *era)
{
if (era->md)
@@ -1514,8 +1501,6 @@ static int era_ctr(struct dm_target *ti, unsigned argc, char **argv)
ti->flush_supported = true;

ti->num_discard_bios = 1;
- era->callbacks.congested_fn = era_is_congested;
- dm_table_add_target_callbacks(ti->table, &era->callbacks);

return 0;
}
diff --git a/drivers/md/dm-raid.c b/drivers/md/dm-raid.c
index 10e8b2fe787b56..d9e270957e1840 100644
--- a/drivers/md/dm-raid.c
+++ b/drivers/md/dm-raid.c
@@ -242,7 +242,6 @@ struct raid_set {

struct mddev md;
struct raid_type *raid_type;
- struct dm_target_callbacks callbacks;

sector_t array_sectors;
sector_t dev_sectors;
@@ -1705,13 +1704,6 @@ static void do_table_event(struct work_struct *ws)
dm_table_event(rs->ti->table);
}

-static int raid_is_congested(struct dm_target_callbacks *cb, int bits)
-{
- struct raid_set *rs = container_of(cb, struct raid_set, callbacks);
-
- return mddev_congested(&rs->md, bits);
-}
-
/*
* Make sure a valid takover (level switch) is being requested on @rs
*
@@ -3248,9 +3240,6 @@ static int raid_ctr(struct dm_target *ti, unsigned int argc, char **argv)
goto bad_md_start;
}

- rs->callbacks.congested_fn = raid_is_congested;
- dm_table_add_target_callbacks(ti->table, &rs->callbacks);
-
/* If raid4/5/6 journal mode explicitly requested (only possible with journal dev) -> set it */
if (test_bit(__CTR_FLAG_JOURNAL_MODE, &rs->ctr_flags)) {
r = r5c_journal_mode_set(&rs->md, rs->journal_dev.mode);
@@ -3310,7 +3299,6 @@ static void raid_dtr(struct dm_target *ti)
{
struct raid_set *rs = ti->private;

- list_del_init(&rs->callbacks.list);
md_stop(&rs->md);
raid_set_free(rs);
}
diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index 8277b959e00bd6..0ea5b7367179ff 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -64,8 +64,6 @@ struct dm_table {
void *event_context;

struct dm_md_mempools *mempools;
-
- struct list_head target_callbacks;
};

/*
@@ -190,7 +188,6 @@ int dm_table_create(struct dm_table **result, fmode_t mode,
return -ENOMEM;

INIT_LIST_HEAD(&t->devices);
- INIT_LIST_HEAD(&t->target_callbacks);

if (!num_targets)
num_targets = KEYS_PER_NODE;
@@ -361,7 +358,7 @@ static int device_area_is_invalid(struct dm_target *ti, struct dm_dev *dev,
* This upgrades the mode on an already open dm_dev, being
* careful to leave things as they were if we fail to reopen the
* device and not to touch the existing bdev field in case
- * it is accessed concurrently inside dm_table_any_congested().
+ * it is accessed concurrently.
*/
static int upgrade_mode(struct dm_dev_internal *dd, fmode_t new_mode,
struct mapped_device *md)
@@ -2052,38 +2049,6 @@ int dm_table_resume_targets(struct dm_table *t)
return 0;
}

-void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb)
-{
- list_add(&cb->list, &t->target_callbacks);
-}
-EXPORT_SYMBOL_GPL(dm_table_add_target_callbacks);
-
-int dm_table_any_congested(struct dm_table *t, int bdi_bits)
-{
- struct dm_dev_internal *dd;
- struct list_head *devices = dm_table_get_devices(t);
- struct dm_target_callbacks *cb;
- int r = 0;
-
- list_for_each_entry(dd, devices, list) {
- struct request_queue *q = bdev_get_queue(dd->dm_dev->bdev);
- char b[BDEVNAME_SIZE];
-
- if (likely(q))
- r |= bdi_congested(q->backing_dev_info, bdi_bits);
- else
- DMWARN_LIMIT("%s: any_congested: nonexistent device %s",
- dm_device_name(t->md),
- bdevname(dd->dm_dev->bdev, b));
- }
-
- list_for_each_entry(cb, &t->target_callbacks, list)
- if (cb->congested_fn)
- r |= cb->congested_fn(cb, bdi_bits);
-
- return r;
-}
-
struct mapped_device *dm_table_get_md(struct dm_table *t)
{
return t->md;
diff --git a/drivers/md/dm-thin.c b/drivers/md/dm-thin.c
index fa8d5464c1fb51..e95682e09d5af8 100644
--- a/drivers/md/dm-thin.c
+++ b/drivers/md/dm-thin.c
@@ -326,7 +326,6 @@ struct pool_c {
struct pool *pool;
struct dm_dev *data_dev;
struct dm_dev *metadata_dev;
- struct dm_target_callbacks callbacks;

dm_block_t low_water_blocks;
struct pool_features requested_pf; /* Features requested during table load */
@@ -2796,18 +2795,6 @@ static int thin_bio_map(struct dm_target *ti, struct bio *bio)
}
}

-static int pool_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
-{
- struct pool_c *pt = container_of(cb, struct pool_c, callbacks);
- struct request_queue *q;
-
- if (get_pool_mode(pt->pool) == PM_OUT_OF_DATA_SPACE)
- return 1;
-
- q = bdev_get_queue(pt->data_dev->bdev);
- return bdi_congested(q->backing_dev_info, bdi_bits);
-}
-
static void requeue_bios(struct pool *pool)
{
struct thin_c *tc;
@@ -3420,9 +3407,6 @@ static int pool_ctr(struct dm_target *ti, unsigned argc, char **argv)
dm_pool_register_pre_commit_callback(pool->pmd,
metadata_pre_commit_callback, pool);

- pt->callbacks.congested_fn = pool_is_congested;
- dm_table_add_target_callbacks(ti->table, &pt->callbacks);
-
mutex_unlock(&dm_thin_pool_table.mutex);

return 0;
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 97838b6d0b5473..f0fd8822da514f 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -1825,31 +1825,6 @@ static blk_qc_t dm_make_request(struct request_queue *q, struct bio *bio)
return ret;
}

-static int dm_any_congested(void *congested_data, int bdi_bits)
-{
- int r = bdi_bits;
- struct mapped_device *md = congested_data;
- struct dm_table *map;
-
- if (!test_bit(DMF_BLOCK_IO_FOR_SUSPEND, &md->flags)) {
- if (dm_request_based(md)) {
- /*
- * With request-based DM we only need to check the
- * top-level queue for congestion.
- */
- struct backing_dev_info *bdi = md->queue->backing_dev_info;
- r = bdi->wb.congested & bdi_bits;
- } else {
- map = dm_get_live_table_fast(md);
- if (map)
- r = dm_table_any_congested(map, bdi_bits);
- dm_put_live_table_fast(md);
- }
- }
-
- return r;
-}
-
/*-----------------------------------------------------------------
* An IDR is used to keep track of allocated minor numbers.
*---------------------------------------------------------------*/
@@ -2289,12 +2264,6 @@ struct queue_limits *dm_get_queue_limits(struct mapped_device *md)
}
EXPORT_SYMBOL_GPL(dm_get_queue_limits);

-static void dm_init_congested_fn(struct mapped_device *md)
-{
- md->queue->backing_dev_info->congested_data = md;
- md->queue->backing_dev_info->congested_fn = dm_any_congested;
-}
-
/*
* Setup the DM device's queue based on md's type
*/
@@ -2311,12 +2280,10 @@ int dm_setup_md_queue(struct mapped_device *md, struct dm_table *t)
DMERR("Cannot initialize queue for request-based dm-mq mapped device");
return r;
}
- dm_init_congested_fn(md);
break;
case DM_TYPE_BIO_BASED:
case DM_TYPE_DAX_BIO_BASED:
case DM_TYPE_NVME_BIO_BASED:
- dm_init_congested_fn(md);
break;
case DM_TYPE_NONE:
WARN_ON_ONCE(true);
diff --git a/drivers/md/dm.h b/drivers/md/dm.h
index d7c4f6606b5fca..4f5fe664d05ac7 100644
--- a/drivers/md/dm.h
+++ b/drivers/md/dm.h
@@ -63,7 +63,6 @@ void dm_table_presuspend_targets(struct dm_table *t);
void dm_table_presuspend_undo_targets(struct dm_table *t);
void dm_table_postsuspend_targets(struct dm_table *t);
int dm_table_resume_targets(struct dm_table *t);
-int dm_table_any_congested(struct dm_table *t, int bdi_bits);
enum dm_queue_mode dm_table_get_type(struct dm_table *t);
struct target_type *dm_table_get_immutable_target_type(struct dm_table *t);
struct dm_target *dm_table_get_immutable_target(struct dm_table *t);
diff --git a/drivers/md/md-linear.c b/drivers/md/md-linear.c
index 26c75c0199fa1b..e19d1919a753d2 100644
--- a/drivers/md/md-linear.c
+++ b/drivers/md/md-linear.c
@@ -46,29 +46,6 @@ static inline struct dev_info *which_dev(struct mddev *mddev, sector_t sector)
return conf->disks + lo;
}

-/*
- * In linear_congested() conf->raid_disks is used as a copy of
- * mddev->raid_disks to iterate conf->disks[], because conf->raid_disks
- * and conf->disks[] are created in linear_conf(), they are always
- * consitent with each other, but mddev->raid_disks does not.
- */
-static int linear_congested(struct mddev *mddev, int bits)
-{
- struct linear_conf *conf;
- int i, ret = 0;
-
- rcu_read_lock();
- conf = rcu_dereference(mddev->private);
-
- for (i = 0; i < conf->raid_disks && !ret ; i++) {
- struct request_queue *q = bdev_get_queue(conf->disks[i].rdev->bdev);
- ret |= bdi_congested(q->backing_dev_info, bits);
- }
-
- rcu_read_unlock();
- return ret;
-}
-
static sector_t linear_size(struct mddev *mddev, sector_t sectors, int raid_disks)
{
struct linear_conf *conf;
@@ -322,7 +299,6 @@ static struct md_personality linear_personality =
.hot_add_disk = linear_add,
.size = linear_size,
.quiesce = linear_quiesce,
- .congested = linear_congested,
};

static int __init linear_init (void)
diff --git a/drivers/md/md-multipath.c b/drivers/md/md-multipath.c
index 152f9e65a22665..f9c895fa9afc25 100644
--- a/drivers/md/md-multipath.c
+++ b/drivers/md/md-multipath.c
@@ -151,28 +151,6 @@ static void multipath_status(struct seq_file *seq, struct mddev *mddev)
seq_putc(seq, ']');
}

-static int multipath_congested(struct mddev *mddev, int bits)
-{
- struct mpconf *conf = mddev->private;
- int i, ret = 0;
-
- rcu_read_lock();
- for (i = 0; i < mddev->raid_disks ; i++) {
- struct md_rdev *rdev = rcu_dereference(conf->multipaths[i].rdev);
- if (rdev && !test_bit(Faulty, &rdev->flags)) {
- struct request_queue *q = bdev_get_queue(rdev->bdev);
-
- ret |= bdi_congested(q->backing_dev_info, bits);
- /* Just like multipath_map, we just check the
- * first available device
- */
- break;
- }
- }
- rcu_read_unlock();
- return ret;
-}
-
/*
* Careful, this can execute in IRQ contexts as well!
*/
@@ -478,7 +456,6 @@ static struct md_personality multipath_personality =
.hot_add_disk = multipath_add_disk,
.hot_remove_disk= multipath_remove_disk,
.size = multipath_size,
- .congested = multipath_congested,
};

static int __init multipath_init (void)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index f567f536b529bd..b27038246bc563 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -549,26 +549,6 @@ void mddev_resume(struct mddev *mddev)
}
EXPORT_SYMBOL_GPL(mddev_resume);

-int mddev_congested(struct mddev *mddev, int bits)
-{
- struct md_personality *pers = mddev->pers;
- int ret = 0;
-
- rcu_read_lock();
- if (mddev->suspended)
- ret = 1;
- else if (pers && pers->congested)
- ret = pers->congested(mddev, bits);
- rcu_read_unlock();
- return ret;
-}
-EXPORT_SYMBOL_GPL(mddev_congested);
-static int md_congested(void *data, int bits)
-{
- struct mddev *mddev = data;
- return mddev_congested(mddev, bits);
-}
-
/*
* Generic flush handling for md
*/
@@ -5964,8 +5944,6 @@ int md_run(struct mddev *mddev)
blk_queue_flag_set(QUEUE_FLAG_NONROT, mddev->queue);
else
blk_queue_flag_clear(QUEUE_FLAG_NONROT, mddev->queue);
- mddev->queue->backing_dev_info->congested_data = mddev;
- mddev->queue->backing_dev_info->congested_fn = md_congested;
}
if (pers->sync_request) {
if (mddev->kobj.sd &&
@@ -6350,7 +6328,6 @@ static int do_md_stop(struct mddev *mddev, int mode,

__md_stop_writes(mddev);
__md_stop(mddev);
- mddev->queue->backing_dev_info->congested_fn = NULL;

/* tell userspace to handle 'inactive' */
sysfs_notify_dirent_safe(mddev->sysfs_state);
diff --git a/drivers/md/md.h b/drivers/md/md.h
index 612814d07d35ab..e2f1ad9afc4885 100644
--- a/drivers/md/md.h
+++ b/drivers/md/md.h
@@ -597,9 +597,6 @@ struct md_personality
* array.
*/
void *(*takeover) (struct mddev *mddev);
- /* congested implements bdi.congested_fn().
- * Will not be called while array is 'suspended' */
- int (*congested)(struct mddev *mddev, int bits);
/* Changes the consistency policy of an active array. */
int (*change_consistency_policy)(struct mddev *mddev, const char *buf);
};
@@ -710,7 +707,6 @@ extern void md_done_sync(struct mddev *mddev, int blocks, int ok);
extern void md_error(struct mddev *mddev, struct md_rdev *rdev);
extern void md_finish_reshape(struct mddev *mddev);

-extern int mddev_congested(struct mddev *mddev, int bits);
extern bool __must_check md_flush_request(struct mddev *mddev, struct bio *bio);
extern void md_super_write(struct mddev *mddev, struct md_rdev *rdev,
sector_t sector, int size, struct page *page);
diff --git a/drivers/md/raid0.c b/drivers/md/raid0.c
index 322386ff5d225d..d092b88af80a66 100644
--- a/drivers/md/raid0.c
+++ b/drivers/md/raid0.c
@@ -29,21 +29,6 @@ module_param(default_layout, int, 0644);
(1L << MD_HAS_PPL) | \
(1L << MD_HAS_MULTIPLE_PPLS))

-static int raid0_congested(struct mddev *mddev, int bits)
-{
- struct r0conf *conf = mddev->private;
- struct md_rdev **devlist = conf->devlist;
- int raid_disks = conf->strip_zone[0].nb_dev;
- int i, ret = 0;
-
- for (i = 0; i < raid_disks && !ret ; i++) {
- struct request_queue *q = bdev_get_queue(devlist[i]->bdev);
-
- ret |= bdi_congested(q->backing_dev_info, bits);
- }
- return ret;
-}
-
/*
* inform the user of the raid configuration
*/
@@ -818,7 +803,6 @@ static struct md_personality raid0_personality=
.size = raid0_size,
.takeover = raid0_takeover,
.quiesce = raid0_quiesce,
- .congested = raid0_congested,
};

static int __init raid0_init (void)
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index dcd27f3da84eca..4edc7ff05ed278 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -786,36 +786,6 @@ static int read_balance(struct r1conf *conf, struct r1bio *r1_bio, int *max_sect
return best_disk;
}

-static int raid1_congested(struct mddev *mddev, int bits)
-{
- struct r1conf *conf = mddev->private;
- int i, ret = 0;
-
- if ((bits & (1 << WB_async_congested)) &&
- conf->pending_count >= max_queued_requests)
- return 1;
-
- rcu_read_lock();
- for (i = 0; i < conf->raid_disks * 2; i++) {
- struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
- if (rdev && !test_bit(Faulty, &rdev->flags)) {
- struct request_queue *q = bdev_get_queue(rdev->bdev);
-
- BUG_ON(!q);
-
- /* Note the '|| 1' - when read_balance prefers
- * non-congested targets, it can be removed
- */
- if ((bits & (1 << WB_async_congested)) || 1)
- ret |= bdi_congested(q->backing_dev_info, bits);
- else
- ret &= bdi_congested(q->backing_dev_info, bits);
- }
- }
- rcu_read_unlock();
- return ret;
-}
-
static void flush_bio_list(struct r1conf *conf, struct bio *bio)
{
/* flush any pending bitmap writes to disk before proceeding w/ I/O */
@@ -3396,7 +3366,6 @@ static struct md_personality raid1_personality =
.check_reshape = raid1_reshape,
.quiesce = raid1_quiesce,
.takeover = raid1_takeover,
- .congested = raid1_congested,
};

static int __init raid_init(void)
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index ec136e44aef7f8..1768300138b35f 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -848,31 +848,6 @@ static struct md_rdev *read_balance(struct r10conf *conf,
return rdev;
}

-static int raid10_congested(struct mddev *mddev, int bits)
-{
- struct r10conf *conf = mddev->private;
- int i, ret = 0;
-
- if ((bits & (1 << WB_async_congested)) &&
- conf->pending_count >= max_queued_requests)
- return 1;
-
- rcu_read_lock();
- for (i = 0;
- (i < conf->geo.raid_disks || i < conf->prev.raid_disks)
- && ret == 0;
- i++) {
- struct md_rdev *rdev = rcu_dereference(conf->mirrors[i].rdev);
- if (rdev && !test_bit(Faulty, &rdev->flags)) {
- struct request_queue *q = bdev_get_queue(rdev->bdev);
-
- ret |= bdi_congested(q->backing_dev_info, bits);
- }
- }
- rcu_read_unlock();
- return ret;
-}
-
static void flush_pending_writes(struct r10conf *conf)
{
/* Any writes that have been queued but are awaiting
@@ -4929,7 +4904,6 @@ static struct md_personality raid10_personality =
.start_reshape = raid10_start_reshape,
.finish_reshape = raid10_finish_reshape,
.update_reshape_pos = raid10_update_reshape_pos,
- .congested = raid10_congested,
};

static int __init raid_init(void)
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
index ab8067f9ce8c68..229a36a8694f28 100644
--- a/drivers/md/raid5.c
+++ b/drivers/md/raid5.c
@@ -5099,28 +5099,6 @@ static void activate_bit_delay(struct r5conf *conf,
}
}

-static int raid5_congested(struct mddev *mddev, int bits)
-{
- struct r5conf *conf = mddev->private;
-
- /* No difference between reads and writes. Just check
- * how busy the stripe_cache is
- */
-
- if (test_bit(R5_INACTIVE_BLOCKED, &conf->cache_state))
- return 1;
-
- /* Also checks whether there is pressure on r5cache log space */
- if (test_bit(R5C_LOG_TIGHT, &conf->cache_state))
- return 1;
- if (conf->quiesce)
- return 1;
- if (atomic_read(&conf->empty_inactive_list_nr))
- return 1;
-
- return 0;
-}
-
static int in_chunk_boundary(struct mddev *mddev, struct bio *bio)
{
struct r5conf *conf = mddev->private;
@@ -8427,7 +8405,6 @@ static struct md_personality raid6_personality =
.finish_reshape = raid5_finish_reshape,
.quiesce = raid5_quiesce,
.takeover = raid6_takeover,
- .congested = raid5_congested,
.change_consistency_policy = raid5_change_consistency_policy,
};
static struct md_personality raid5_personality =
@@ -8452,7 +8429,6 @@ static struct md_personality raid5_personality =
.finish_reshape = raid5_finish_reshape,
.quiesce = raid5_quiesce,
.takeover = raid5_takeover,
- .congested = raid5_congested,
.change_consistency_policy = raid5_change_consistency_policy,
};

@@ -8478,7 +8454,6 @@ static struct md_personality raid4_personality =
.finish_reshape = raid5_finish_reshape,
.quiesce = raid5_quiesce,
.takeover = raid4_takeover,
- .congested = raid5_congested,
.change_consistency_policy = raid5_change_consistency_policy,
};

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 7c6f0bbb54a5bd..eb5f2506cede72 100644
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -1616,27 +1616,6 @@ struct btrfs_root *btrfs_get_fs_root(struct btrfs_fs_info *fs_info,
return ERR_PTR(ret);
}

-static int btrfs_congested_fn(void *congested_data, int bdi_bits)
-{
- struct btrfs_fs_info *info = (struct btrfs_fs_info *)congested_data;
- int ret = 0;
- struct btrfs_device *device;
- struct backing_dev_info *bdi;
-
- rcu_read_lock();
- list_for_each_entry_rcu(device, &info->fs_devices->devices, dev_list) {
- if (!device->bdev)
- continue;
- bdi = device->bdev->bd_bdi;
- if (bdi_congested(bdi, bdi_bits)) {
- ret = 1;
- break;
- }
- }
- rcu_read_unlock();
- return ret;
-}
-
/*
* called by the kthread helper functions to finally call the bio end_io
* functions. This is where read checksum verification actually happens
@@ -3051,8 +3030,6 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
goto fail_sb_buffer;
}

- sb->s_bdi->congested_fn = btrfs_congested_fn;
- sb->s_bdi->congested_data = fs_info;
sb->s_bdi->capabilities |= BDI_CAP_CGROUP_WRITEBACK;
sb->s_bdi->ra_pages = VM_READAHEAD_PAGES;
sb->s_bdi->ra_pages *= btrfs_super_num_devices(disk_super);
diff --git a/include/linux/backing-dev-defs.h b/include/linux/backing-dev-defs.h
index 1cec4521e1fbe2..fff9367a634856 100644
--- a/include/linux/backing-dev-defs.h
+++ b/include/linux/backing-dev-defs.h
@@ -33,8 +33,6 @@ enum wb_congested_state {
WB_sync_congested, /* The sync queue is getting full */
};

-typedef int (congested_fn)(void *, int);
-
enum wb_stat_item {
WB_RECLAIMABLE,
WB_WRITEBACK,
@@ -170,8 +168,6 @@ struct backing_dev_info {
struct list_head bdi_list;
unsigned long ra_pages; /* max readahead in PAGE_SIZE units */
unsigned long io_pages; /* max allowed IO size */
- congested_fn *congested_fn; /* Function pointer if device is md/dm */
- void *congested_data; /* Pointer to aux data for congested func */

struct kref refcnt; /* Reference counter for the structure */
unsigned int capabilities; /* Device capabilities */
diff --git a/include/linux/backing-dev.h b/include/linux/backing-dev.h
index 9173d2c22b4aa0..0b06b2d26c9aa3 100644
--- a/include/linux/backing-dev.h
+++ b/include/linux/backing-dev.h
@@ -169,10 +169,6 @@ static inline struct backing_dev_info *inode_to_bdi(struct inode *inode)

static inline int wb_congested(struct bdi_writeback *wb, int cong_bits)
{
- struct backing_dev_info *bdi = wb->bdi;
-
- if (bdi->congested_fn)
- return bdi->congested_fn(bdi->congested_data, cong_bits);
return wb->congested & cong_bits;
}

diff --git a/include/linux/device-mapper.h b/include/linux/device-mapper.h
index 8750f2dc5613ab..d5306d9c29c4f2 100644
--- a/include/linux/device-mapper.h
+++ b/include/linux/device-mapper.h
@@ -322,12 +322,6 @@ struct dm_target {
bool discards_supported:1;
};

-/* Each target can link one of these into the table */
-struct dm_target_callbacks {
- struct list_head list;
- int (*congested_fn) (struct dm_target_callbacks *, int);
-};
-
void *dm_per_bio_data(struct bio *bio, size_t data_size);
struct bio *dm_bio_from_per_bio_data(void *data, size_t data_size);
unsigned dm_bio_get_target_bio_nr(const struct bio *bio);
@@ -477,11 +471,6 @@ int dm_table_create(struct dm_table **result, fmode_t mode,
int dm_table_add_target(struct dm_table *t, const char *type,
sector_t start, sector_t len, char *params);

-/*
- * Target_ctr should call this if it needs to add any callbacks.
- */
-void dm_table_add_target_callbacks(struct dm_table *t, struct dm_target_callbacks *cb);
-
/*
* Target can use this to set the table's type.
* Can only ever be called from a target's ctr.
--
2.26.2

2020-07-01 14:48:56

by David Sterba

[permalink] [raw]
Subject: Re: [PATCH 4/4] writeback: remove bdi->congested_fn

On Wed, Jul 01, 2020 at 11:06:22AM +0200, Christoph Hellwig wrote:
> Except for pktdvd, the only places setting congested bits are file
> systems that allocate their own backing_dev_info structures. And
> pktdvd is a deprecated driver that isn't useful in stack setup
> either. So remove the dead congested_fn stacking infrastructure.
>
> Signed-off-by: Christoph Hellwig <[email protected]>
> ---
> drivers/block/drbd/drbd_main.c | 59 --------------------------------
> drivers/md/bcache/request.c | 43 -----------------------
> drivers/md/bcache/super.c | 1 -
> drivers/md/dm-cache-target.c | 19 ----------
> drivers/md/dm-clone-target.c | 15 --------
> drivers/md/dm-era-target.c | 15 --------
> drivers/md/dm-raid.c | 12 -------
> drivers/md/dm-table.c | 37 +-------------------
> drivers/md/dm-thin.c | 16 ---------
> drivers/md/dm.c | 33 ------------------
> drivers/md/dm.h | 1 -
> drivers/md/md-linear.c | 24 -------------
> drivers/md/md-multipath.c | 23 -------------
> drivers/md/md.c | 23 -------------
> drivers/md/md.h | 4 ---
> drivers/md/raid0.c | 16 ---------
> drivers/md/raid1.c | 31 -----------------
> drivers/md/raid10.c | 26 --------------
> drivers/md/raid5.c | 25 --------------

For the btrfs bits

> fs/btrfs/disk-io.c | 23 -------------

Acked-by: David Sterba <[email protected]>

2020-07-01 16:39:06

by Tejun Heo

[permalink] [raw]
Subject: Re: remove dead bdi congestion leftovers

On Wed, Jul 01, 2020 at 11:06:18AM +0200, Christoph Hellwig wrote:
> Hi Jens,
>
> we have a lot of bdi congestion related code that is left around without
> any use. This series removes it in preparation of sorting out the bdi
> lifetime rules properly.

Acked-by: Tejun Heo <[email protected]>

Thanks a lot for killing the dead code.

--
tejun

2020-07-01 17:45:04

by Mike Snitzer

[permalink] [raw]
Subject: Re: remove dead bdi congestion leftovers

On Wed, Jul 01 2020 at 5:06am -0400,
Christoph Hellwig <[email protected]> wrote:

> Hi Jens,
>
> we have a lot of bdi congestion related code that is left around without
> any use. This series removes it in preparation of sorting out the bdi
> lifetime rules properly.

I could do some git archeology to see what the fs, mm and block core
changes were to stop using bdi congested but a pointer to associated
changes (or quick recap) would save me some time.

Also, curious to know how back-pressure should be felt back up the IO
stack now? (apologies if these are well worn topics, I haven't been
tracking this area of development).

Thanks,
Mike

2020-07-01 17:58:22

by Matthew Wilcox

[permalink] [raw]
Subject: Re: remove dead bdi congestion leftovers

On Wed, Jul 01, 2020 at 12:41:03PM -0400, Mike Snitzer wrote:
> On Wed, Jul 01 2020 at 5:06am -0400,
> Christoph Hellwig <[email protected]> wrote:
>
> > Hi Jens,
> >
> > we have a lot of bdi congestion related code that is left around without
> > any use. This series removes it in preparation of sorting out the bdi
> > lifetime rules properly.
>
> I could do some git archeology to see what the fs, mm and block core
> changes were to stop using bdi congested but a pointer to associated
> changes (or quick recap) would save me some time.
>
> Also, curious to know how back-pressure should be felt back up the IO
> stack now? (apologies if these are well worn topics, I haven't been
> tracking this area of development).

It isn't. Jens declared the implementation was broken, and broke it
more. So we're just living with stupid broken timeouts.

2020-07-01 18:27:14

by Matthew Wilcox

[permalink] [raw]
Subject: Re: remove dead bdi congestion leftovers

On Wed, Jul 01, 2020 at 06:57:47PM +0100, Matthew Wilcox wrote:
> On Wed, Jul 01, 2020 at 12:41:03PM -0400, Mike Snitzer wrote:
> > On Wed, Jul 01 2020 at 5:06am -0400,
> > Christoph Hellwig <[email protected]> wrote:
> >
> > > Hi Jens,
> > >
> > > we have a lot of bdi congestion related code that is left around without
> > > any use. This series removes it in preparation of sorting out the bdi
> > > lifetime rules properly.
> >
> > I could do some git archeology to see what the fs, mm and block core
> > changes were to stop using bdi congested but a pointer to associated
> > changes (or quick recap) would save me some time.
> >
> > Also, curious to know how back-pressure should be felt back up the IO
> > stack now? (apologies if these are well worn topics, I haven't been
> > tracking this area of development).
>
> It isn't. Jens declared the implementation was broken, and broke it
> more. So we're just living with stupid broken timeouts.

Here's a thread about it. This would have been a discussion topic at
LSFMM2020, but COVID.

https://lore.kernel.org/linux-mm/[email protected]/T/#u

2020-07-02 00:39:21

by Coly Li

[permalink] [raw]
Subject: Re: [PATCH 4/4] writeback: remove bdi->congested_fn

On 2020/7/1 17:06, Christoph Hellwig wrote:
> Except for pktdvd, the only places setting congested bits are file
> systems that allocate their own backing_dev_info structures. And
> pktdvd is a deprecated driver that isn't useful in stack setup
> either. So remove the dead congested_fn stacking infrastructure.
>
> Signed-off-by: Christoph Hellwig <[email protected]>

For the bcache part, Acked-by: Coly Li <[email protected]>

Thanks.

Coly Li


> ---
> drivers/block/drbd/drbd_main.c | 59 --------------------------------
> drivers/md/bcache/request.c | 43 -----------------------
> drivers/md/bcache/super.c | 1 -
> drivers/md/dm-cache-target.c | 19 ----------
> drivers/md/dm-clone-target.c | 15 --------
> drivers/md/dm-era-target.c | 15 --------
> drivers/md/dm-raid.c | 12 -------
> drivers/md/dm-table.c | 37 +-------------------
> drivers/md/dm-thin.c | 16 ---------
> drivers/md/dm.c | 33 ------------------
> drivers/md/dm.h | 1 -
> drivers/md/md-linear.c | 24 -------------
> drivers/md/md-multipath.c | 23 -------------
> drivers/md/md.c | 23 -------------
> drivers/md/md.h | 4 ---
> drivers/md/raid0.c | 16 ---------
> drivers/md/raid1.c | 31 -----------------
> drivers/md/raid10.c | 26 --------------
> drivers/md/raid5.c | 25 --------------
> fs/btrfs/disk-io.c | 23 -------------
> include/linux/backing-dev-defs.h | 4 ---
> include/linux/backing-dev.h | 4 ---
> include/linux/device-mapper.h | 11 ------
> 23 files changed, 1 insertion(+), 464 deletions(-)
>

[snipped]

> diff --git a/drivers/md/bcache/request.c b/drivers/md/bcache/request.c
> index 7acf024e99f351..cda05fc61c3afa 100644
> --- a/drivers/md/bcache/request.c
> +++ b/drivers/md/bcache/request.c
> @@ -1228,36 +1228,10 @@ static int cached_dev_ioctl(struct bcache_device *d, fmode_t mode,
> return __blkdev_driver_ioctl(dc->bdev, mode, cmd, arg);
> }
>
> -static int cached_dev_congested(void *data, int bits)
> -{
> - struct bcache_device *d = data;
> - struct cached_dev *dc = container_of(d, struct cached_dev, disk);
> - struct request_queue *q = bdev_get_queue(dc->bdev);
> - int ret = 0;
> -
> - if (bdi_congested(q->backing_dev_info, bits))
> - return 1;
> -
> - if (cached_dev_get(dc)) {
> - unsigned int i;
> - struct cache *ca;
> -
> - for_each_cache(ca, d->c, i) {
> - q = bdev_get_queue(ca->bdev);
> - ret |= bdi_congested(q->backing_dev_info, bits);
> - }
> -
> - cached_dev_put(dc);
> - }
> -
> - return ret;
> -}
> -
> void bch_cached_dev_request_init(struct cached_dev *dc)
> {
> struct gendisk *g = dc->disk.disk;
>
> - g->queue->backing_dev_info->congested_fn = cached_dev_congested;
> dc->disk.cache_miss = cached_dev_cache_miss;
> dc->disk.ioctl = cached_dev_ioctl;
> }
> @@ -1342,27 +1316,10 @@ static int flash_dev_ioctl(struct bcache_device *d, fmode_t mode,
> return -ENOTTY;
> }
>
> -static int flash_dev_congested(void *data, int bits)
> -{
> - struct bcache_device *d = data;
> - struct request_queue *q;
> - struct cache *ca;
> - unsigned int i;
> - int ret = 0;
> -
> - for_each_cache(ca, d->c, i) {
> - q = bdev_get_queue(ca->bdev);
> - ret |= bdi_congested(q->backing_dev_info, bits);
> - }
> -
> - return ret;
> -}
> -
> void bch_flash_dev_request_init(struct bcache_device *d)
> {
> struct gendisk *g = d->disk;
>
> - g->queue->backing_dev_info->congested_fn = flash_dev_congested;
> d->cache_miss = flash_dev_cache_miss;
> d->ioctl = flash_dev_ioctl;
> }
> diff --git a/drivers/md/bcache/super.c b/drivers/md/bcache/super.c
> index 2014016f9a60d3..1810d7ca2f6653 100644
> --- a/drivers/md/bcache/super.c
> +++ b/drivers/md/bcache/super.c
> @@ -877,7 +877,6 @@ static int bcache_device_init(struct bcache_device *d, unsigned int block_size,
>
> d->disk->queue = q;
> q->queuedata = d;
> - q->backing_dev_info->congested_data = d;
> q->limits.max_hw_sectors = UINT_MAX;
> q->limits.max_sectors = UINT_MAX;
> q->limits.max_segment_size = UINT_MAX;
> diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
> index d3bb355819a421..24549dc92eeec5 100644
> --- a/drivers/md/dm-cache-target.c
> +++ b/drivers/md/dm-cache-target.c
> @@ -421,8 +421,6 @@ struct cache {
>
> struct rw_semaphore quiesce_lock;
>
> - struct dm_target_callbacks callbacks;
> -
> /*
> * origin_blocks entries, discarded if set.
> */
> @@ -2423,20 +2421,6 @@ static void set_cache_size(struct cache *cache, dm_cblock_t size)
> cache->cache_size = size;
> }
>
> -static int is_congested(struct dm_dev *dev, int bdi_bits)
> -{
> - struct request_queue *q = bdev_get_queue(dev->bdev);
> - return bdi_congested(q->backing_dev_info, bdi_bits);
> -}
> -
> -static int cache_is_congested(struct dm_target_callbacks *cb, int bdi_bits)
> -{
> - struct cache *cache = container_of(cb, struct cache, callbacks);
> -
> - return is_congested(cache->origin_dev, bdi_bits) ||
> - is_congested(cache->cache_dev, bdi_bits);
> -}
> -
> #define DEFAULT_MIGRATION_THRESHOLD 2048
>
> static int cache_create(struct cache_args *ca, struct cache **result)
> @@ -2471,9 +2455,6 @@ static int cache_create(struct cache_args *ca, struct cache **result)
> goto bad;
> }
>
> - cache->callbacks.congested_fn = cache_is_congested;
> - dm_table_add_target_callbacks(ti->table, &cache->callbacks);
> -
> cache->metadata_dev = ca->metadata_dev;
> cache->origin_dev = ca->origin_dev;
> cache->cache_dev = ca->cache_dev;

[snipped]

2020-07-02 05:37:10

by Song Liu

[permalink] [raw]
Subject: Re: [PATCH 4/4] writeback: remove bdi->congested_fn

On Wed, Jul 1, 2020 at 2:06 AM Christoph Hellwig <[email protected]> wrote:
>
> Except for pktdvd, the only places setting congested bits are file
> systems that allocate their own backing_dev_info structures. And
> pktdvd is a deprecated driver that isn't useful in stack setup
> either. So remove the dead congested_fn stacking infrastructure.
>
> Signed-off-by: Christoph Hellwig <[email protected]>

For md bits:

Acked-by: Song Liu <[email protected]>

2020-07-08 23:17:30

by Jens Axboe

[permalink] [raw]
Subject: Re: remove dead bdi congestion leftovers

On 7/1/20 3:06 AM, Christoph Hellwig wrote:
> Hi Jens,
>
> we have a lot of bdi congestion related code that is left around without
> any use. This series removes it in preparation of sorting out the bdi
> lifetime rules properly.

Please run series like this through a full compilation, for both this one
and the previous series I had to fix up issues like this:

drivers/md/bcache/request.c: In function ‘bch_cached_dev_request_init’:
drivers/md/bcache/request.c:1233:18: warning: unused variable ‘g’ [-Wunused-variable]
1233 | struct gendisk *g = dc->disk.disk;
| ^
drivers/md/bcache/request.c: In function ‘bch_flash_dev_request_init’:
drivers/md/bcache/request.c:1320:18: warning: unused variable ‘g’ [-Wunused-variable]
1320 | struct gendisk *g = d->disk;
| ^

Did the same here, applied it.

--
Jens Axboe

2020-07-09 05:35:29

by Christoph Hellwig

[permalink] [raw]
Subject: Re: remove dead bdi congestion leftovers

On Wed, Jul 08, 2020 at 05:14:29PM -0600, Jens Axboe wrote:
> On 7/1/20 3:06 AM, Christoph Hellwig wrote:
> > Hi Jens,
> >
> > we have a lot of bdi congestion related code that is left around without
> > any use. This series removes it in preparation of sorting out the bdi
> > lifetime rules properly.
>
> Please run series like this through a full compilation, for both this one
> and the previous series I had to fix up issues like this:
>
> drivers/md/bcache/request.c: In function ‘bch_cached_dev_request_init’:
> drivers/md/bcache/request.c:1233:18: warning: unused variable ‘g’ [-Wunused-variable]
> 1233 | struct gendisk *g = dc->disk.disk;
> | ^
> drivers/md/bcache/request.c: In function ‘bch_flash_dev_request_init’:
> drivers/md/bcache/request.c:1320:18: warning: unused variable ‘g’ [-Wunused-variable]
> 1320 | struct gendisk *g = d->disk;
> | ^
>
> Did the same here, applied it.

And just like the previous one I did, and the compiler did not complain.
There must be something about certain gcc versions not warning about
variables that are initialized but not otherwise used.

2020-07-09 13:59:38

by Jens Axboe

[permalink] [raw]
Subject: Re: remove dead bdi congestion leftovers

On 7/8/20 11:32 PM, Christoph Hellwig wrote:
> On Wed, Jul 08, 2020 at 05:14:29PM -0600, Jens Axboe wrote:
>> On 7/1/20 3:06 AM, Christoph Hellwig wrote:
>>> Hi Jens,
>>>
>>> we have a lot of bdi congestion related code that is left around without
>>> any use. This series removes it in preparation of sorting out the bdi
>>> lifetime rules properly.
>>
>> Please run series like this through a full compilation, for both this one
>> and the previous series I had to fix up issues like this:
>>
>> drivers/md/bcache/request.c: In function ‘bch_cached_dev_request_init’:
>> drivers/md/bcache/request.c:1233:18: warning: unused variable ‘g’ [-Wunused-variable]
>> 1233 | struct gendisk *g = dc->disk.disk;
>> | ^
>> drivers/md/bcache/request.c: In function ‘bch_flash_dev_request_init’:
>> drivers/md/bcache/request.c:1320:18: warning: unused variable ‘g’ [-Wunused-variable]
>> 1320 | struct gendisk *g = d->disk;
>> | ^
>>
>> Did the same here, applied it.
>
> And just like the previous one I did, and the compiler did not complain.
> There must be something about certain gcc versions not warning about
> variables that are initialized but not otherwise used.

Are you using gcc-10? It sucks for that. gcc-9 seems to reliably hit
these cases for me, not sure why gcc-10 doesn't. And the ones quoted
above are about as trivial as they can get.

--
Jens Axboe

2020-07-09 14:02:29

by Christoph Hellwig

[permalink] [raw]
Subject: Re: remove dead bdi congestion leftovers

On Thu, Jul 09, 2020 at 07:58:58AM -0600, Jens Axboe wrote:
> On 7/8/20 11:32 PM, Christoph Hellwig wrote:
> > On Wed, Jul 08, 2020 at 05:14:29PM -0600, Jens Axboe wrote:
> >> On 7/1/20 3:06 AM, Christoph Hellwig wrote:
> >>> Hi Jens,
> >>>
> >>> we have a lot of bdi congestion related code that is left around without
> >>> any use. This series removes it in preparation of sorting out the bdi
> >>> lifetime rules properly.
> >>
> >> Please run series like this through a full compilation, for both this one
> >> and the previous series I had to fix up issues like this:
> >>
> >> drivers/md/bcache/request.c: In function ‘bch_cached_dev_request_init’:
> >> drivers/md/bcache/request.c:1233:18: warning: unused variable ‘g’ [-Wunused-variable]
> >> 1233 | struct gendisk *g = dc->disk.disk;
> >> | ^
> >> drivers/md/bcache/request.c: In function ‘bch_flash_dev_request_init’:
> >> drivers/md/bcache/request.c:1320:18: warning: unused variable ‘g’ [-Wunused-variable]
> >> 1320 | struct gendisk *g = d->disk;
> >> | ^
> >>
> >> Did the same here, applied it.
> >
> > And just like the previous one I did, and the compiler did not complain.
> > There must be something about certain gcc versions not warning about
> > variables that are initialized but not otherwise used.
>
> Are you using gcc-10? It sucks for that. gcc-9 seems to reliably hit
> these cases for me, not sure why gcc-10 doesn't. And the ones quoted
> above are about as trivial as they can get.

gcc-9.3 from Debian -testing. And yes, I'm really surprised it didn't
find those.