bdi: Add bdi->id
There currently is no way to universally identify and lookup a bdi without holding a reference and pointer to it. This patch adds an non-recycling bdi->id and implements bdi_get_by_id() which looks up bdis by their ids. This will be used by memcg foreign inode flushing. I left bdi_list alone for simplicity and because while rb_tree does support rcu assignment it doesn't seem to guarantee lossless walk when walk is racing aginst tree rebalance operations. Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Jens Axboe <axboe@kernel.dk>alistair/sunxi64-5.4-dsi
parent
5b9cce4c7e
commit
34f8fe501f
|
@ -185,6 +185,8 @@ struct bdi_writeback {
|
||||||
};
|
};
|
||||||
|
|
||||||
struct backing_dev_info {
|
struct backing_dev_info {
|
||||||
|
u64 id;
|
||||||
|
struct rb_node rb_node; /* keyed by ->id */
|
||||||
struct list_head bdi_list;
|
struct list_head bdi_list;
|
||||||
unsigned long ra_pages; /* max readahead in PAGE_SIZE units */
|
unsigned long ra_pages; /* max readahead in PAGE_SIZE units */
|
||||||
unsigned long io_pages; /* max allowed IO size */
|
unsigned long io_pages; /* max allowed IO size */
|
||||||
|
|
|
@ -24,6 +24,7 @@ static inline struct backing_dev_info *bdi_get(struct backing_dev_info *bdi)
|
||||||
return bdi;
|
return bdi;
|
||||||
}
|
}
|
||||||
|
|
||||||
|
struct backing_dev_info *bdi_get_by_id(u64 id);
|
||||||
void bdi_put(struct backing_dev_info *bdi);
|
void bdi_put(struct backing_dev_info *bdi);
|
||||||
|
|
||||||
__printf(2, 3)
|
__printf(2, 3)
|
||||||
|
|
|
@ -1,6 +1,7 @@
|
||||||
// SPDX-License-Identifier: GPL-2.0-only
|
// SPDX-License-Identifier: GPL-2.0-only
|
||||||
|
|
||||||
#include <linux/wait.h>
|
#include <linux/wait.h>
|
||||||
|
#include <linux/rbtree.h>
|
||||||
#include <linux/backing-dev.h>
|
#include <linux/backing-dev.h>
|
||||||
#include <linux/kthread.h>
|
#include <linux/kthread.h>
|
||||||
#include <linux/freezer.h>
|
#include <linux/freezer.h>
|
||||||
|
@ -22,10 +23,12 @@ EXPORT_SYMBOL_GPL(noop_backing_dev_info);
|
||||||
static struct class *bdi_class;
|
static struct class *bdi_class;
|
||||||
|
|
||||||
/*
|
/*
|
||||||
* bdi_lock protects updates to bdi_list. bdi_list has RCU reader side
|
* bdi_lock protects bdi_tree and updates to bdi_list. bdi_list has RCU
|
||||||
* locking.
|
* reader side locking.
|
||||||
*/
|
*/
|
||||||
DEFINE_SPINLOCK(bdi_lock);
|
DEFINE_SPINLOCK(bdi_lock);
|
||||||
|
static u64 bdi_id_cursor;
|
||||||
|
static struct rb_root bdi_tree = RB_ROOT;
|
||||||
LIST_HEAD(bdi_list);
|
LIST_HEAD(bdi_list);
|
||||||
|
|
||||||
/* bdi_wq serves all asynchronous writeback tasks */
|
/* bdi_wq serves all asynchronous writeback tasks */
|
||||||
|
@ -859,9 +862,58 @@ struct backing_dev_info *bdi_alloc_node(gfp_t gfp_mask, int node_id)
|
||||||
}
|
}
|
||||||
EXPORT_SYMBOL(bdi_alloc_node);
|
EXPORT_SYMBOL(bdi_alloc_node);
|
||||||
|
|
||||||
|
static struct rb_node **bdi_lookup_rb_node(u64 id, struct rb_node **parentp)
|
||||||
|
{
|
||||||
|
struct rb_node **p = &bdi_tree.rb_node;
|
||||||
|
struct rb_node *parent = NULL;
|
||||||
|
struct backing_dev_info *bdi;
|
||||||
|
|
||||||
|
lockdep_assert_held(&bdi_lock);
|
||||||
|
|
||||||
|
while (*p) {
|
||||||
|
parent = *p;
|
||||||
|
bdi = rb_entry(parent, struct backing_dev_info, rb_node);
|
||||||
|
|
||||||
|
if (bdi->id > id)
|
||||||
|
p = &(*p)->rb_left;
|
||||||
|
else if (bdi->id < id)
|
||||||
|
p = &(*p)->rb_right;
|
||||||
|
else
|
||||||
|
break;
|
||||||
|
}
|
||||||
|
|
||||||
|
if (parentp)
|
||||||
|
*parentp = parent;
|
||||||
|
return p;
|
||||||
|
}
|
||||||
|
|
||||||
|
/**
|
||||||
|
* bdi_get_by_id - lookup and get bdi from its id
|
||||||
|
* @id: bdi id to lookup
|
||||||
|
*
|
||||||
|
* Find bdi matching @id and get it. Returns NULL if the matching bdi
|
||||||
|
* doesn't exist or is already unregistered.
|
||||||
|
*/
|
||||||
|
struct backing_dev_info *bdi_get_by_id(u64 id)
|
||||||
|
{
|
||||||
|
struct backing_dev_info *bdi = NULL;
|
||||||
|
struct rb_node **p;
|
||||||
|
|
||||||
|
spin_lock_bh(&bdi_lock);
|
||||||
|
p = bdi_lookup_rb_node(id, NULL);
|
||||||
|
if (*p) {
|
||||||
|
bdi = rb_entry(*p, struct backing_dev_info, rb_node);
|
||||||
|
bdi_get(bdi);
|
||||||
|
}
|
||||||
|
spin_unlock_bh(&bdi_lock);
|
||||||
|
|
||||||
|
return bdi;
|
||||||
|
}
|
||||||
|
|
||||||
int bdi_register_va(struct backing_dev_info *bdi, const char *fmt, va_list args)
|
int bdi_register_va(struct backing_dev_info *bdi, const char *fmt, va_list args)
|
||||||
{
|
{
|
||||||
struct device *dev;
|
struct device *dev;
|
||||||
|
struct rb_node *parent, **p;
|
||||||
|
|
||||||
if (bdi->dev) /* The driver needs to use separate queues per device */
|
if (bdi->dev) /* The driver needs to use separate queues per device */
|
||||||
return 0;
|
return 0;
|
||||||
|
@ -877,7 +929,15 @@ int bdi_register_va(struct backing_dev_info *bdi, const char *fmt, va_list args)
|
||||||
set_bit(WB_registered, &bdi->wb.state);
|
set_bit(WB_registered, &bdi->wb.state);
|
||||||
|
|
||||||
spin_lock_bh(&bdi_lock);
|
spin_lock_bh(&bdi_lock);
|
||||||
|
|
||||||
|
bdi->id = ++bdi_id_cursor;
|
||||||
|
|
||||||
|
p = bdi_lookup_rb_node(bdi->id, &parent);
|
||||||
|
rb_link_node(&bdi->rb_node, parent, p);
|
||||||
|
rb_insert_color(&bdi->rb_node, &bdi_tree);
|
||||||
|
|
||||||
list_add_tail_rcu(&bdi->bdi_list, &bdi_list);
|
list_add_tail_rcu(&bdi->bdi_list, &bdi_list);
|
||||||
|
|
||||||
spin_unlock_bh(&bdi_lock);
|
spin_unlock_bh(&bdi_lock);
|
||||||
|
|
||||||
trace_writeback_bdi_register(bdi);
|
trace_writeback_bdi_register(bdi);
|
||||||
|
@ -918,6 +978,7 @@ EXPORT_SYMBOL(bdi_register_owner);
|
||||||
static void bdi_remove_from_list(struct backing_dev_info *bdi)
|
static void bdi_remove_from_list(struct backing_dev_info *bdi)
|
||||||
{
|
{
|
||||||
spin_lock_bh(&bdi_lock);
|
spin_lock_bh(&bdi_lock);
|
||||||
|
rb_erase(&bdi->rb_node, &bdi_tree);
|
||||||
list_del_rcu(&bdi->bdi_list);
|
list_del_rcu(&bdi->bdi_list);
|
||||||
spin_unlock_bh(&bdi_lock);
|
spin_unlock_bh(&bdi_lock);
|
||||||
|
|
||||||
|
|
Loading…
Reference in New Issue