From ccb820dc7d2236b1af0d54ae038a27b5b6d5ae5a Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Mon, 13 Mar 2023 15:12:29 -0700 Subject: fscrypt: destroy keyring after security_sb_delete() fscrypt_destroy_keyring() must be called after all potentially-encrypted inodes were evicted; otherwise it cannot safely destroy the keyring. Since inodes that are in-use by the Landlock LSM don't get evicted until security_sb_delete(), this means that fscrypt_destroy_keyring() must be called *after* security_sb_delete(). This fixes a WARN_ON followed by a NULL dereference, only possible if Landlock was being used on encrypted files. Fixes: d7e7b9af104c ("fscrypt: stop using keyrings subsystem for fscrypt_master_key") Cc: stable@vger.kernel.org Reported-by: syzbot+93e495f6a4f748827c88@syzkaller.appspotmail.com Link: https://lore.kernel.org/r/00000000000044651705f6ca1e30@google.com Reviewed-by: Christian Brauner Link: https://lore.kernel.org/r/20230313221231.272498-2-ebiggers@kernel.org Signed-off-by: Eric Biggers --- fs/super.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) (limited to 'fs/super.c') diff --git a/fs/super.c b/fs/super.c index 84332d5cb817..04bc62ab7dfe 100644 --- a/fs/super.c +++ b/fs/super.c @@ -475,13 +475,22 @@ void generic_shutdown_super(struct super_block *sb) cgroup_writeback_umount(); - /* evict all inodes with zero refcount */ + /* Evict all inodes with zero refcount. */ evict_inodes(sb); - /* only nonzero refcount inodes can have marks */ + + /* + * Clean up and evict any inodes that still have references due + * to fsnotify or the security policy. + */ fsnotify_sb_delete(sb); - fscrypt_destroy_keyring(sb); security_sb_delete(sb); + /* + * Now that all potentially-encrypted inodes have been evicted, + * the fscrypt keyring can be destroyed. + */ + fscrypt_destroy_keyring(sb); + if (sb->s_dio_done_wq) { destroy_workqueue(sb->s_dio_done_wq); sb->s_dio_done_wq = NULL; -- cgit v1.2.3 From cf2e309ebca7bb0916771839f9b580b06c778530 Mon Sep 17 00:00:00 2001 From: Qi Zheng Date: Mon, 13 Mar 2023 19:28:19 +0800 Subject: mm: shrinkers: convert shrinker_rwsem to mutex MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Now there are no readers of shrinker_rwsem, so we can simply replace it with mutex lock. Link: https://lkml.kernel.org/r/20230313112819.38938-9-zhengqi.arch@bytedance.com Signed-off-by: Qi Zheng Acked-by: Vlastimil Babka Acked-by: Kirill Tkhai Acked-by: Roman Gushchin Cc: Christian König Cc: David Hildenbrand Cc: Davidlohr Bueso Cc: Johannes Weiner Cc: Michal Hocko Cc: Muchun Song Cc: Paul E. McKenney Cc: Shakeel Butt Cc: Sultan Alsawaf Cc: Tetsuo Handa Cc: Yang Shi Signed-off-by: Andrew Morton --- drivers/md/dm-cache-metadata.c | 2 +- drivers/md/dm-thin-metadata.c | 2 +- fs/super.c | 2 +- mm/shrinker_debug.c | 14 +++++++------- mm/vmscan.c | 34 +++++++++++++++++----------------- 5 files changed, 27 insertions(+), 27 deletions(-) (limited to 'fs/super.c') diff --git a/drivers/md/dm-cache-metadata.c b/drivers/md/dm-cache-metadata.c index acffed750e3e..9e0c69958587 100644 --- a/drivers/md/dm-cache-metadata.c +++ b/drivers/md/dm-cache-metadata.c @@ -1828,7 +1828,7 @@ int dm_cache_metadata_abort(struct dm_cache_metadata *cmd) * Replacement block manager (new_bm) is created and old_bm destroyed outside of * cmd root_lock to avoid ABBA deadlock that would result (due to life-cycle of * shrinker associated with the block manager's bufio client vs cmd root_lock). - * - must take shrinker_rwsem without holding cmd->root_lock + * - must take shrinker_mutex without holding cmd->root_lock */ new_bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT, CACHE_MAX_CONCURRENT_LOCKS); diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c index fd464fb024c3..9f5cb52c5763 100644 --- a/drivers/md/dm-thin-metadata.c +++ b/drivers/md/dm-thin-metadata.c @@ -1887,7 +1887,7 @@ int dm_pool_abort_metadata(struct dm_pool_metadata *pmd) * Replacement block manager (new_bm) is created and old_bm destroyed outside of * pmd root_lock to avoid ABBA deadlock that would result (due to life-cycle of * shrinker associated with the block manager's bufio client vs pmd root_lock). - * - must take shrinker_rwsem without holding pmd->root_lock + * - must take shrinker_mutex without holding pmd->root_lock */ new_bm = dm_block_manager_create(pmd->bdev, THIN_METADATA_BLOCK_SIZE << SECTOR_SHIFT, THIN_MAX_CONCURRENT_LOCKS); diff --git a/fs/super.c b/fs/super.c index 04bc62ab7dfe..34afe411cf2b 100644 --- a/fs/super.c +++ b/fs/super.c @@ -54,7 +54,7 @@ static char *sb_writers_name[SB_FREEZE_LEVELS] = { * One thing we have to be careful of with a per-sb shrinker is that we don't * drop the last active reference to the superblock from within the shrinker. * If that happens we could trigger unregistering the shrinker from within the - * shrinker path and that leads to deadlock on the shrinker_rwsem. Hence we + * shrinker path and that leads to deadlock on the shrinker_mutex. Hence we * take a passive reference to the superblock to avoid this from occurring. */ static unsigned long super_cache_scan(struct shrinker *shrink, diff --git a/mm/shrinker_debug.c b/mm/shrinker_debug.c index 37d54d037495..fdd155fd35ed 100644 --- a/mm/shrinker_debug.c +++ b/mm/shrinker_debug.c @@ -8,7 +8,7 @@ #include /* defined in vmscan.c */ -extern struct rw_semaphore shrinker_rwsem; +extern struct mutex shrinker_mutex; extern struct list_head shrinker_list; extern struct srcu_struct shrinker_srcu; @@ -168,7 +168,7 @@ int shrinker_debugfs_add(struct shrinker *shrinker) char buf[128]; int id; - lockdep_assert_held(&shrinker_rwsem); + lockdep_assert_held(&shrinker_mutex); /* debugfs isn't initialized yet, add debugfs entries later. */ if (!shrinker_debugfs_root) @@ -211,7 +211,7 @@ int shrinker_debugfs_rename(struct shrinker *shrinker, const char *fmt, ...) if (!new) return -ENOMEM; - down_write(&shrinker_rwsem); + mutex_lock(&shrinker_mutex); old = shrinker->name; shrinker->name = new; @@ -229,7 +229,7 @@ int shrinker_debugfs_rename(struct shrinker *shrinker, const char *fmt, ...) shrinker->debugfs_entry = entry; } - up_write(&shrinker_rwsem); + mutex_unlock(&shrinker_mutex); kfree_const(old); @@ -241,7 +241,7 @@ struct dentry *shrinker_debugfs_remove(struct shrinker *shrinker) { struct dentry *entry = shrinker->debugfs_entry; - lockdep_assert_held(&shrinker_rwsem); + lockdep_assert_held(&shrinker_mutex); kfree_const(shrinker->name); shrinker->name = NULL; @@ -266,14 +266,14 @@ static int __init shrinker_debugfs_init(void) shrinker_debugfs_root = dentry; /* Create debugfs entries for shrinkers registered at boot */ - down_write(&shrinker_rwsem); + mutex_lock(&shrinker_mutex); list_for_each_entry(shrinker, &shrinker_list, list) if (!shrinker->debugfs_entry) { ret = shrinker_debugfs_add(shrinker); if (ret) break; } - up_write(&shrinker_rwsem); + mutex_unlock(&shrinker_mutex); return ret; } diff --git a/mm/vmscan.c b/mm/vmscan.c index 2b22a42d83c4..8faac4310cb5 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -35,7 +35,7 @@ #include #include #include -#include +#include #include #include #include @@ -202,7 +202,7 @@ static void set_task_reclaim_state(struct task_struct *task, } LIST_HEAD(shrinker_list); -DECLARE_RWSEM(shrinker_rwsem); +DEFINE_MUTEX(shrinker_mutex); DEFINE_SRCU(shrinker_srcu); static atomic_t shrinker_srcu_generation = ATOMIC_INIT(0); @@ -225,7 +225,7 @@ static struct shrinker_info *shrinker_info_protected(struct mem_cgroup *memcg, { return srcu_dereference_check(memcg->nodeinfo[nid]->shrinker_info, &shrinker_srcu, - lockdep_is_held(&shrinker_rwsem)); + lockdep_is_held(&shrinker_mutex)); } static struct shrinker_info *shrinker_info_srcu(struct mem_cgroup *memcg, @@ -304,7 +304,7 @@ int alloc_shrinker_info(struct mem_cgroup *memcg) int nid, size, ret = 0; int map_size, defer_size = 0; - down_write(&shrinker_rwsem); + mutex_lock(&shrinker_mutex); map_size = shrinker_map_size(shrinker_nr_max); defer_size = shrinker_defer_size(shrinker_nr_max); size = map_size + defer_size; @@ -320,7 +320,7 @@ int alloc_shrinker_info(struct mem_cgroup *memcg) info->map_nr_max = shrinker_nr_max; rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_info, info); } - up_write(&shrinker_rwsem); + mutex_unlock(&shrinker_mutex); return ret; } @@ -336,7 +336,7 @@ static int expand_shrinker_info(int new_id) if (!root_mem_cgroup) goto out; - lockdep_assert_held(&shrinker_rwsem); + lockdep_assert_held(&shrinker_mutex); map_size = shrinker_map_size(new_nr_max); defer_size = shrinker_defer_size(new_nr_max); @@ -386,7 +386,7 @@ static int prealloc_memcg_shrinker(struct shrinker *shrinker) if (mem_cgroup_disabled()) return -ENOSYS; - down_write(&shrinker_rwsem); + mutex_lock(&shrinker_mutex); id = idr_alloc(&shrinker_idr, shrinker, 0, 0, GFP_KERNEL); if (id < 0) goto unlock; @@ -400,7 +400,7 @@ static int prealloc_memcg_shrinker(struct shrinker *shrinker) shrinker->id = id; ret = 0; unlock: - up_write(&shrinker_rwsem); + mutex_unlock(&shrinker_mutex); return ret; } @@ -410,7 +410,7 @@ static void unregister_memcg_shrinker(struct shrinker *shrinker) BUG_ON(id < 0); - lockdep_assert_held(&shrinker_rwsem); + lockdep_assert_held(&shrinker_mutex); idr_remove(&shrinker_idr, id); } @@ -445,7 +445,7 @@ void reparent_shrinker_deferred(struct mem_cgroup *memcg) parent = root_mem_cgroup; /* Prevent from concurrent shrinker_info expand */ - down_write(&shrinker_rwsem); + mutex_lock(&shrinker_mutex); for_each_node(nid) { child_info = shrinker_info_protected(memcg, nid); parent_info = shrinker_info_protected(parent, nid); @@ -454,7 +454,7 @@ void reparent_shrinker_deferred(struct mem_cgroup *memcg) atomic_long_add(nr, &parent_info->nr_deferred[i]); } } - up_write(&shrinker_rwsem); + mutex_unlock(&shrinker_mutex); } static bool cgroup_reclaim(struct scan_control *sc) @@ -703,9 +703,9 @@ void free_prealloced_shrinker(struct shrinker *shrinker) shrinker->name = NULL; #endif if (shrinker->flags & SHRINKER_MEMCG_AWARE) { - down_write(&shrinker_rwsem); + mutex_lock(&shrinker_mutex); unregister_memcg_shrinker(shrinker); - up_write(&shrinker_rwsem); + mutex_unlock(&shrinker_mutex); return; } @@ -715,11 +715,11 @@ void free_prealloced_shrinker(struct shrinker *shrinker) void register_shrinker_prepared(struct shrinker *shrinker) { - down_write(&shrinker_rwsem); + mutex_lock(&shrinker_mutex); list_add_tail_rcu(&shrinker->list, &shrinker_list); shrinker->flags |= SHRINKER_REGISTERED; shrinker_debugfs_add(shrinker); - up_write(&shrinker_rwsem); + mutex_unlock(&shrinker_mutex); } static int __register_shrinker(struct shrinker *shrinker) @@ -769,13 +769,13 @@ void unregister_shrinker(struct shrinker *shrinker) if (!(shrinker->flags & SHRINKER_REGISTERED)) return; - down_write(&shrinker_rwsem); + mutex_lock(&shrinker_mutex); list_del_rcu(&shrinker->list); shrinker->flags &= ~SHRINKER_REGISTERED; if (shrinker->flags & SHRINKER_MEMCG_AWARE) unregister_memcg_shrinker(shrinker); debugfs_entry = shrinker_debugfs_remove(shrinker); - up_write(&shrinker_rwsem); + mutex_unlock(&shrinker_mutex); atomic_inc(&shrinker_srcu_generation); synchronize_srcu(&shrinker_srcu); -- cgit v1.2.3 From 47a7c01c3efc6581f5dcca40928baeb38e1e40c2 Mon Sep 17 00:00:00 2001 From: Qi Zheng Date: Fri, 9 Jun 2023 08:15:12 +0000 Subject: Revert "mm: shrinkers: convert shrinker_rwsem to mutex" Patch series "revert shrinker_srcu related changes". This patch (of 7): This reverts commit cf2e309ebca7bb0916771839f9b580b06c778530. Kernel test robot reports -88.8% regression in stress-ng.ramfs.ops_per_sec test case [1], which is caused by commit f95bdb700bc6 ("mm: vmscan: make global slab shrink lockless"). The root cause is that SRCU has to be careful to not frequently check for SRCU read-side critical section exits. Therefore, even if no one is currently in the SRCU read-side critical section, synchronize_srcu() cannot return quickly. That's why unregister_shrinker() has become slower. After discussion, we will try to use the refcount+RCU method [2] proposed by Dave Chinner to continue to re-implement the lockless slab shrink. So revert the shrinker_mutex back to shrinker_rwsem first. [1]. https://lore.kernel.org/lkml/202305230837.db2c233f-yujie.liu@intel.com/ [2]. https://lore.kernel.org/lkml/ZIJhou1d55d4H1s0@dread.disaster.area/ Link: https://lkml.kernel.org/r/20230609081518.3039120-1-qi.zheng@linux.dev Link: https://lkml.kernel.org/r/20230609081518.3039120-2-qi.zheng@linux.dev Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-lkp/202305230837.db2c233f-yujie.liu@intel.com Signed-off-by: Qi Zheng Cc: Dave Chinner Cc: Kirill Tkhai Cc: Muchun Song Cc: Roman Gushchin Cc: Vlastimil Babka Cc: Yujie Liu Signed-off-by: Andrew Morton --- drivers/md/dm-cache-metadata.c | 2 +- drivers/md/dm-thin-metadata.c | 2 +- fs/super.c | 2 +- mm/shrinker_debug.c | 14 +++++++------- mm/vmscan.c | 34 +++++++++++++++++----------------- 5 files changed, 27 insertions(+), 27 deletions(-) (limited to 'fs/super.c') diff --git a/drivers/md/dm-cache-metadata.c b/drivers/md/dm-cache-metadata.c index 9e0c69958587..acffed750e3e 100644 --- a/drivers/md/dm-cache-metadata.c +++ b/drivers/md/dm-cache-metadata.c @@ -1828,7 +1828,7 @@ int dm_cache_metadata_abort(struct dm_cache_metadata *cmd) * Replacement block manager (new_bm) is created and old_bm destroyed outside of * cmd root_lock to avoid ABBA deadlock that would result (due to life-cycle of * shrinker associated with the block manager's bufio client vs cmd root_lock). - * - must take shrinker_mutex without holding cmd->root_lock + * - must take shrinker_rwsem without holding cmd->root_lock */ new_bm = dm_block_manager_create(cmd->bdev, DM_CACHE_METADATA_BLOCK_SIZE << SECTOR_SHIFT, CACHE_MAX_CONCURRENT_LOCKS); diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c index 9f5cb52c5763..fd464fb024c3 100644 --- a/drivers/md/dm-thin-metadata.c +++ b/drivers/md/dm-thin-metadata.c @@ -1887,7 +1887,7 @@ int dm_pool_abort_metadata(struct dm_pool_metadata *pmd) * Replacement block manager (new_bm) is created and old_bm destroyed outside of * pmd root_lock to avoid ABBA deadlock that would result (due to life-cycle of * shrinker associated with the block manager's bufio client vs pmd root_lock). - * - must take shrinker_mutex without holding pmd->root_lock + * - must take shrinker_rwsem without holding pmd->root_lock */ new_bm = dm_block_manager_create(pmd->bdev, THIN_METADATA_BLOCK_SIZE << SECTOR_SHIFT, THIN_MAX_CONCURRENT_LOCKS); diff --git a/fs/super.c b/fs/super.c index 34afe411cf2b..04bc62ab7dfe 100644 --- a/fs/super.c +++ b/fs/super.c @@ -54,7 +54,7 @@ static char *sb_writers_name[SB_FREEZE_LEVELS] = { * One thing we have to be careful of with a per-sb shrinker is that we don't * drop the last active reference to the superblock from within the shrinker. * If that happens we could trigger unregistering the shrinker from within the - * shrinker path and that leads to deadlock on the shrinker_mutex. Hence we + * shrinker path and that leads to deadlock on the shrinker_rwsem. Hence we * take a passive reference to the superblock to avoid this from occurring. */ static unsigned long super_cache_scan(struct shrinker *shrink, diff --git a/mm/shrinker_debug.c b/mm/shrinker_debug.c index fe10436d9911..2be15b8a6d0b 100644 --- a/mm/shrinker_debug.c +++ b/mm/shrinker_debug.c @@ -8,7 +8,7 @@ #include /* defined in vmscan.c */ -extern struct mutex shrinker_mutex; +extern struct rw_semaphore shrinker_rwsem; extern struct list_head shrinker_list; extern struct srcu_struct shrinker_srcu; @@ -168,7 +168,7 @@ int shrinker_debugfs_add(struct shrinker *shrinker) char buf[128]; int id; - lockdep_assert_held(&shrinker_mutex); + lockdep_assert_held(&shrinker_rwsem); /* debugfs isn't initialized yet, add debugfs entries later. */ if (!shrinker_debugfs_root) @@ -211,7 +211,7 @@ int shrinker_debugfs_rename(struct shrinker *shrinker, const char *fmt, ...) if (!new) return -ENOMEM; - mutex_lock(&shrinker_mutex); + down_write(&shrinker_rwsem); old = shrinker->name; shrinker->name = new; @@ -229,7 +229,7 @@ int shrinker_debugfs_rename(struct shrinker *shrinker, const char *fmt, ...) shrinker->debugfs_entry = entry; } - mutex_unlock(&shrinker_mutex); + up_write(&shrinker_rwsem); kfree_const(old); @@ -242,7 +242,7 @@ struct dentry *shrinker_debugfs_detach(struct shrinker *shrinker, { struct dentry *entry = shrinker->debugfs_entry; - lockdep_assert_held(&shrinker_mutex); + lockdep_assert_held(&shrinker_rwsem); kfree_const(shrinker->name); shrinker->name = NULL; @@ -271,14 +271,14 @@ static int __init shrinker_debugfs_init(void) shrinker_debugfs_root = dentry; /* Create debugfs entries for shrinkers registered at boot */ - mutex_lock(&shrinker_mutex); + down_write(&shrinker_rwsem); list_for_each_entry(shrinker, &shrinker_list, list) if (!shrinker->debugfs_entry) { ret = shrinker_debugfs_add(shrinker); if (ret) break; } - mutex_unlock(&shrinker_mutex); + up_write(&shrinker_rwsem); return ret; } diff --git a/mm/vmscan.c b/mm/vmscan.c index 6d0cd2840cf0..4730dba253c8 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -35,7 +35,7 @@ #include #include #include -#include +#include #include #include #include @@ -190,7 +190,7 @@ struct scan_control { int vm_swappiness = 60; LIST_HEAD(shrinker_list); -DEFINE_MUTEX(shrinker_mutex); +DECLARE_RWSEM(shrinker_rwsem); DEFINE_SRCU(shrinker_srcu); static atomic_t shrinker_srcu_generation = ATOMIC_INIT(0); @@ -213,7 +213,7 @@ static struct shrinker_info *shrinker_info_protected(struct mem_cgroup *memcg, { return srcu_dereference_check(memcg->nodeinfo[nid]->shrinker_info, &shrinker_srcu, - lockdep_is_held(&shrinker_mutex)); + lockdep_is_held(&shrinker_rwsem)); } static struct shrinker_info *shrinker_info_srcu(struct mem_cgroup *memcg, @@ -292,7 +292,7 @@ int alloc_shrinker_info(struct mem_cgroup *memcg) int nid, size, ret = 0; int map_size, defer_size = 0; - mutex_lock(&shrinker_mutex); + down_write(&shrinker_rwsem); map_size = shrinker_map_size(shrinker_nr_max); defer_size = shrinker_defer_size(shrinker_nr_max); size = map_size + defer_size; @@ -308,7 +308,7 @@ int alloc_shrinker_info(struct mem_cgroup *memcg) info->map_nr_max = shrinker_nr_max; rcu_assign_pointer(memcg->nodeinfo[nid]->shrinker_info, info); } - mutex_unlock(&shrinker_mutex); + up_write(&shrinker_rwsem); return ret; } @@ -324,7 +324,7 @@ static int expand_shrinker_info(int new_id) if (!root_mem_cgroup) goto out; - lockdep_assert_held(&shrinker_mutex); + lockdep_assert_held(&shrinker_rwsem); map_size = shrinker_map_size(new_nr_max); defer_size = shrinker_defer_size(new_nr_max); @@ -374,7 +374,7 @@ static int prealloc_memcg_shrinker(struct shrinker *shrinker) if (mem_cgroup_disabled()) return -ENOSYS; - mutex_lock(&shrinker_mutex); + down_write(&shrinker_rwsem); id = idr_alloc(&shrinker_idr, shrinker, 0, 0, GFP_KERNEL); if (id < 0) goto unlock; @@ -388,7 +388,7 @@ static int prealloc_memcg_shrinker(struct shrinker *shrinker) shrinker->id = id; ret = 0; unlock: - mutex_unlock(&shrinker_mutex); + up_write(&shrinker_rwsem); return ret; } @@ -398,7 +398,7 @@ static void unregister_memcg_shrinker(struct shrinker *shrinker) BUG_ON(id < 0); - lockdep_assert_held(&shrinker_mutex); + lockdep_assert_held(&shrinker_rwsem); idr_remove(&shrinker_idr, id); } @@ -433,7 +433,7 @@ void reparent_shrinker_deferred(struct mem_cgroup *memcg) parent = root_mem_cgroup; /* Prevent from concurrent shrinker_info expand */ - mutex_lock(&shrinker_mutex); + down_write(&shrinker_rwsem); for_each_node(nid) { child_info = shrinker_info_protected(memcg, nid); parent_info = shrinker_info_protected(parent, nid); @@ -442,7 +442,7 @@ void reparent_shrinker_deferred(struct mem_cgroup *memcg) atomic_long_add(nr, &parent_info->nr_deferred[i]); } } - mutex_unlock(&shrinker_mutex); + up_write(&shrinker_rwsem); } static bool cgroup_reclaim(struct scan_control *sc) @@ -743,9 +743,9 @@ void free_prealloced_shrinker(struct shrinker *shrinker) shrinker->name = NULL; #endif if (shrinker->flags & SHRINKER_MEMCG_AWARE) { - mutex_lock(&shrinker_mutex); + down_write(&shrinker_rwsem); unregister_memcg_shrinker(shrinker); - mutex_unlock(&shrinker_mutex); + up_write(&shrinker_rwsem); return; } @@ -755,11 +755,11 @@ void free_prealloced_shrinker(struct shrinker *shrinker) void register_shrinker_prepared(struct shrinker *shrinker) { - mutex_lock(&shrinker_mutex); + down_write(&shrinker_rwsem); list_add_tail_rcu(&shrinker->list, &shrinker_list); shrinker->flags |= SHRINKER_REGISTERED; shrinker_debugfs_add(shrinker); - mutex_unlock(&shrinker_mutex); + up_write(&shrinker_rwsem); } static int __register_shrinker(struct shrinker *shrinker) @@ -810,13 +810,13 @@ void unregister_shrinker(struct shrinker *shrinker) if (!(shrinker->flags & SHRINKER_REGISTERED)) return; - mutex_lock(&shrinker_mutex); + down_write(&shrinker_rwsem); list_del_rcu(&shrinker->list); shrinker->flags &= ~SHRINKER_REGISTERED; if (shrinker->flags & SHRINKER_MEMCG_AWARE) unregister_memcg_shrinker(shrinker); debugfs_entry = shrinker_debugfs_detach(shrinker, &debugfs_id); - mutex_unlock(&shrinker_mutex); + up_write(&shrinker_rwsem); atomic_inc(&shrinker_srcu_generation); synchronize_srcu(&shrinker_srcu); -- cgit v1.2.3