Subject: linux-next: build failure after merge of the bcachefs tree

From: Stephen Rothwell <[email-masked]>
Date: Tue, 12 Sep 2023 12:04:29 +1000

Hi all,

After merging the bcachefs tree, today's linux-next build (x86_64
allmodconfig) failed like this:

fs/bcachefs/btree_cache.c: In function 'bch2_fs_btree_cache_exit':
fs/bcachefs/btree_cache.c:403:9: error: implicit declaration of function 'unregister_shrinker'; did you mean 'unregister_chrdev'? [-Werror=implicit-function-declaration]
  403 |         unregister_shrinker(&bc->shrink);
      |         ^~~~~~~~~~~~~~~~~~~
      |         unregister_chrdev
fs/bcachefs/btree_cache.c: In function 'bch2_fs_btree_cache_init':
fs/bcachefs/btree_cache.c:479:15: error: implicit declaration of function 'register_shrinker'; did you mean 'register_chrdev'? [-Werror=implicit-function-declaration]
  479 |         ret = register_shrinker(&bc->shrink, "%s/btree_cache", c->name);
      |               ^~~~~~~~~~~~~~~~~
      |               register_chrdev
cc1: all warnings being treated as errors

Caused by commits

  5ec30115c066 ("bcachefs: Initial commit")

interacting with commit

  eba045d9350d ("mm: shrinker: remove old APIs")

from v6.6-rc1.

I have applied the following merge resolution patch for today.  More may
be needed.

From 801ad185700d9a7abcf156233b9db6cf6d831581 Mon Sep 17 00:00:00 2001
From: Stephen Rothwell <[email-masked]>
Date: Tue, 12 Sep 2023 11:27:22 +1000
Subject: [PATCH] bcachefs: convert to dynamically allocated shrinkers

Signed-off-by: Stephen Rothwell <[email-masked]>
---
 fs/bcachefs/btree_cache.c     | 19 +++++++++++--------
 fs/bcachefs/btree_key_cache.c | 18 +++++++++++-------
 fs/bcachefs/btree_types.h     |  4 ++--
 fs/bcachefs/fs.c              |  2 +-
 fs/bcachefs/sysfs.c           |  2 +-
 5 files changed, 26 insertions(+), 19 deletions(-)

diff --git a/fs/bcachefs/btree_cache.c b/fs/bcachefs/btree_cache.c
index 245ddd92b2d1..7f0eded6c296 100644
--- a/fs/bcachefs/btree_cache.c
+++ b/fs/bcachefs/btree_cache.c
@@ -285,7 +285,7 @@ static int btree_node_write_and_reclaim(struct bch_fs *c, struct btree *b)
 static unsigned long bch2_btree_cache_scan(struct shrinker *shrink,
 					   struct shrink_control *sc)
 {
-	struct bch_fs *c = container_of(shrink, struct bch_fs,
+	struct bch_fs *c = container_of(&shrink, struct bch_fs,
 					btree_cache.shrink);
 	struct btree_cache *bc = &c->btree_cache;
 	struct btree *b, *t;
@@ -384,7 +384,7 @@ static unsigned long bch2_btree_cache_scan(struct shrinker *shrink,
 static unsigned long bch2_btree_cache_count(struct shrinker *shrink,
 					    struct shrink_control *sc)
 {
-	struct bch_fs *c = container_of(shrink, struct bch_fs,
+	struct bch_fs *c = container_of(&shrink, struct bch_fs,
 					btree_cache.shrink);
 	struct btree_cache *bc = &c->btree_cache;
 
@@ -400,7 +400,7 @@ void bch2_fs_btree_cache_exit(struct bch_fs *c)
 	struct btree *b;
 	unsigned i, flags;
 
-	unregister_shrinker(&bc->shrink);
+	shrinker_free(bc->shrink);
 
 	/* vfree() can allocate memory: */
 	flags = memalloc_nofs_save();
@@ -454,6 +454,7 @@ void bch2_fs_btree_cache_exit(struct bch_fs *c)
 int bch2_fs_btree_cache_init(struct bch_fs *c)
 {
 	struct btree_cache *bc = &c->btree_cache;
+	struct shrinker *shrink;
 	unsigned i;
 	int ret = 0;
 
@@ -473,12 +474,14 @@ int bch2_fs_btree_cache_init(struct bch_fs *c)
 
 	mutex_init(&c->verify_lock);
 
-	bc->shrink.count_objects	= bch2_btree_cache_count;
-	bc->shrink.scan_objects		= bch2_btree_cache_scan;
-	bc->shrink.seeks		= 4;
-	ret = register_shrinker(&bc->shrink, "%s/btree_cache", c->name);
-	if (ret)
+	shrink = shrinker_alloc(0, "%s/btree_cache", c->name);
+	if (!shrink)
 		goto err;
+	bc->shrink = shrink;
+	shrink->count_objects	= bch2_btree_cache_count;
+	shrink->scan_objects	= bch2_btree_cache_scan;
+	shrink->seeks		= 4;
+	shrinker_register(shrink);
 
 	return 0;
 err:
diff --git a/fs/bcachefs/btree_key_cache.c b/fs/bcachefs/btree_key_cache.c
index 505e7c365ab7..88d33690233b 100644
--- a/fs/bcachefs/btree_key_cache.c
+++ b/fs/bcachefs/btree_key_cache.c
@@ -838,7 +838,7 @@ void bch2_btree_key_cache_drop(struct btree_trans *trans,
 static unsigned long bch2_btree_key_cache_scan(struct shrinker *shrink,
 					   struct shrink_control *sc)
 {
-	struct bch_fs *c = container_of(shrink, struct bch_fs,
+	struct bch_fs *c = container_of(&shrink, struct bch_fs,
 					btree_key_cache.shrink);
 	struct btree_key_cache *bc = &c->btree_key_cache;
 	struct bucket_table *tbl;
@@ -936,7 +936,7 @@ static unsigned long bch2_btree_key_cache_scan(struct shrinker *shrink,
 static unsigned long bch2_btree_key_cache_count(struct shrinker *shrink,
 					    struct shrink_control *sc)
 {
-	struct bch_fs *c = container_of(shrink, struct bch_fs,
+	struct bch_fs *c = container_of(&shrink, struct bch_fs,
 					btree_key_cache.shrink);
 	struct btree_key_cache *bc = &c->btree_key_cache;
 	long nr = atomic_long_read(&bc->nr_keys) -
@@ -957,7 +957,7 @@ void bch2_fs_btree_key_cache_exit(struct btree_key_cache *bc)
 	int cpu;
 #endif
 
-	unregister_shrinker(&bc->shrink);
+	shrinker_free(bc->shrink);
 
 	mutex_lock(&bc->lock);
 
@@ -1031,6 +1031,7 @@ void bch2_fs_btree_key_cache_init_early(struct btree_key_cache *c)
 int bch2_fs_btree_key_cache_init(struct btree_key_cache *bc)
 {
 	struct bch_fs *c = container_of(bc, struct bch_fs, btree_key_cache);
+	struct shrinker *shrink;
 
 #ifdef __KERNEL__
 	bc->pcpu_freed = alloc_percpu(struct btree_key_cache_freelist);
@@ -1043,11 +1044,14 @@ int bch2_fs_btree_key_cache_init(struct btree_key_cache *bc)
 
 	bc->table_init_done = true;
 
-	bc->shrink.seeks		= 0;
-	bc->shrink.count_objects	= bch2_btree_key_cache_count;
-	bc->shrink.scan_objects		= bch2_btree_key_cache_scan;
-	if (register_shrinker(&bc->shrink, "%s/btree_key_cache", c->name))
+	shrink = shrinker_alloc(0, "%s/btree_key_cache", c->name);
+	if (!shrink)
 		return -BCH_ERR_ENOMEM_fs_btree_cache_init;
+	bc->shrink = shrink;
+	shrink->seeks		= 0;
+	shrink->count_objects	= bch2_btree_key_cache_count;
+	shrink->scan_objects	= bch2_btree_key_cache_scan;
+	shrinker_register(shrink);
 	return 0;
 }
 
diff --git a/fs/bcachefs/btree_types.h b/fs/bcachefs/btree_types.h
index 70398aaa095e..fac0abdaf167 100644
--- a/fs/bcachefs/btree_types.h
+++ b/fs/bcachefs/btree_types.h
@@ -163,7 +163,7 @@ struct btree_cache {
 	unsigned		used;
 	unsigned		reserve;
 	atomic_t		dirty;
-	struct shrinker		shrink;
+	struct shrinker		*shrink;
 
 	/*
 	 * If we need to allocate memory for a new btree node and that
@@ -321,7 +321,7 @@ struct btree_key_cache {
 	bool			table_init_done;
 	struct list_head	freed_pcpu;
 	struct list_head	freed_nonpcpu;
-	struct shrinker		shrink;
+	struct shrinker		*shrink;
 	unsigned		shrink_iter;
 	struct btree_key_cache_freelist __percpu *pcpu_freed;
 
diff --git a/fs/bcachefs/fs.c b/fs/bcachefs/fs.c
index 48431700b83e..bdc8573631bd 100644
--- a/fs/bcachefs/fs.c
+++ b/fs/bcachefs/fs.c
@@ -1885,7 +1885,7 @@ static struct dentry *bch2_mount(struct file_system_type *fs_type,
 		sb->s_flags	|= SB_POSIXACL;
 #endif
 
-	sb->s_shrink.seeks = 0;
+	sb->s_shrink->seeks = 0;
 
 	vinode = bch2_vfs_inode_get(c, BCACHEFS_ROOT_SUBVOL_INUM);
 	ret = PTR_ERR_OR_ZERO(vinode);
diff --git a/fs/bcachefs/sysfs.c b/fs/bcachefs/sysfs.c
index 41c6900c34c1..a9f480c26bb4 100644
--- a/fs/bcachefs/sysfs.c
+++ b/fs/bcachefs/sysfs.c
@@ -522,7 +522,7 @@ STORE(bch2_fs)
 
 		sc.gfp_mask = GFP_KERNEL;
 		sc.nr_to_scan = strtoul_or_return(buf);
-		c->btree_cache.shrink.scan_objects(&c->btree_cache.shrink, &sc);
+		c->btree_cache.shrink->scan_objects(c->btree_cache.shrink, &sc);
 	}
 
 	if (attr == &sysfs_btree_wakeup)
-- 
2.40.1

-- 
Cheers,
Stephen Rothwell