[PATCH 15/19] kernfs: split ->kill_sb
From: Christoph Hellwig
Date: Wed Sep 13 2023 - 07:11:58 EST
Split the kernfs_kill_sb helper into helpers for the new split
shutdown_sb and free_sb methods. Note that resctrl has very odd
locking in ->kill_sb, so this commit only releases the locking
acquired in rdt_shutdown_sb in rdt_free_sb. This is not very good
code and relies on ->shutdown_sb and ->free_sb to always be called
in pairs, which it currently is. The next commit will try to clean
this up.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
arch/x86/kernel/cpu/resctrl/rdtgroup.c | 12 +++++++++---
fs/kernfs/mount.c | 18 ++++++++----------
fs/sysfs/mount.c | 7 ++++---
include/linux/kernfs.h | 5 ++---
kernel/cgroup/cgroup.c | 10 ++++++----
5 files changed, 29 insertions(+), 23 deletions(-)
diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
index 725344048f85da..8db767fd80df6b 100644
--- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
+++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
@@ -2772,7 +2772,7 @@ static void rmdir_all_sub(void)
kernfs_remove(kn_mondata);
}
-static void rdt_kill_sb(struct super_block *sb)
+static void rdt_shutdown_sb(struct super_block *sb)
{
struct rdt_resource *r;
@@ -2792,7 +2792,12 @@ static void rdt_kill_sb(struct super_block *sb)
static_branch_disable_cpuslocked(&rdt_alloc_enable_key);
static_branch_disable_cpuslocked(&rdt_mon_enable_key);
static_branch_disable_cpuslocked(&rdt_enable_key);
- kernfs_kill_sb(sb);
+ kernfs_shutdown_sb(sb);
+}
+
+static void rdt_free_sb(struct super_block *sb)
+{
+ kernfs_free_sb(sb);
mutex_unlock(&rdtgroup_mutex);
cpus_read_unlock();
}
@@ -2801,7 +2806,8 @@ static struct file_system_type rdt_fs_type = {
.name = "resctrl",
.init_fs_context = rdt_init_fs_context,
.parameters = rdt_fs_parameters,
- .kill_sb = rdt_kill_sb,
+ .shutdown_sb = rdt_shutdown_sb,
+ .free_sb = rdt_free_sb,
};
static int mon_addfile(struct kernfs_node *parent_kn, const char *name,
diff --git a/fs/kernfs/mount.c b/fs/kernfs/mount.c
index d6d3cba669dbdd..32ec4ec3c878f6 100644
--- a/fs/kernfs/mount.c
+++ b/fs/kernfs/mount.c
@@ -379,14 +379,14 @@ void kernfs_free_fs_context(struct fs_context *fc)
}
/**
- * kernfs_kill_sb - kill_sb for kernfs
+ * kernfs_shutdown_sb - shutdown_sb for kernfs
* @sb: super_block being killed
*
- * This can be used directly for file_system_type->kill_sb(). If a kernfs
- * user needs extra cleanup, it can implement its own kill_sb() and call
+ * This can be used directly for file_system_type->shutdown_sb(). If a kernfs
+ * user needs extra cleanup, it can implement its own shutdown_sb() and call
* this function at the end.
*/
-void kernfs_kill_sb(struct super_block *sb)
+void kernfs_shutdown_sb(struct super_block *sb)
{
struct kernfs_super_info *info = kernfs_info(sb);
struct kernfs_root *root = info->root;
@@ -394,13 +394,11 @@ void kernfs_kill_sb(struct super_block *sb)
down_write(&root->kernfs_supers_rwsem);
list_del(&info->node);
up_write(&root->kernfs_supers_rwsem);
+}
- /*
- * Remove the superblock from fs_supers/s_instances
- * so we can't find it, before freeing kernfs_super_info.
- */
- generic_shutdown_super(sb);
- kfree(info);
+void kernfs_free_sb(struct super_block *sb)
+{
+ kfree(kernfs_info(sb));
}
static void __init kernfs_mutex_init(void)
diff --git a/fs/sysfs/mount.c b/fs/sysfs/mount.c
index 98467bb7673781..804391342599bc 100644
--- a/fs/sysfs/mount.c
+++ b/fs/sysfs/mount.c
@@ -79,18 +79,19 @@ static int sysfs_init_fs_context(struct fs_context *fc)
return 0;
}
-static void sysfs_kill_sb(struct super_block *sb)
+static void sysfs_free_sb(struct super_block *sb)
{
void *ns = (void *)kernfs_super_ns(sb);
- kernfs_kill_sb(sb);
+ kernfs_free_sb(sb);
kobj_ns_drop(KOBJ_NS_TYPE_NET, ns);
}
static struct file_system_type sysfs_fs_type = {
.name = "sysfs",
.init_fs_context = sysfs_init_fs_context,
- .kill_sb = sysfs_kill_sb,
+ .shutdown_sb = kernfs_shutdown_sb,
+ .free_sb = sysfs_free_sb,
.fs_flags = FS_USERNS_MOUNT,
};
diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
index 2a36f3218b5106..940059251deac8 100644
--- a/include/linux/kernfs.h
+++ b/include/linux/kernfs.h
@@ -453,7 +453,8 @@ int kernfs_xattr_set(struct kernfs_node *kn, const char *name,
const void *kernfs_super_ns(struct super_block *sb);
int kernfs_get_tree(struct fs_context *fc);
void kernfs_free_fs_context(struct fs_context *fc);
-void kernfs_kill_sb(struct super_block *sb);
+void kernfs_shutdown_sb(struct super_block *sb);
+void kernfs_free_sb(struct super_block *sb);
void kernfs_init(void);
@@ -572,8 +573,6 @@ static inline int kernfs_get_tree(struct fs_context *fc)
static inline void kernfs_free_fs_context(struct fs_context *fc) { }
-static inline void kernfs_kill_sb(struct super_block *sb) { }
-
static inline void kernfs_init(void) { }
#endif /* CONFIG_KERNFS */
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c
index 1fb7f562289d53..a6c5e6ed1b6e2d 100644
--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -2249,7 +2249,7 @@ static int cgroup_init_fs_context(struct fs_context *fc)
return 0;
}
-static void cgroup_kill_sb(struct super_block *sb)
+static void cgroup_shutdown_sb(struct super_block *sb)
{
struct kernfs_root *kf_root = kernfs_root_from_sb(sb);
struct cgroup_root *root = cgroup_root_from_kf(kf_root);
@@ -2266,14 +2266,15 @@ static void cgroup_kill_sb(struct super_block *sb)
percpu_ref_kill(&root->cgrp.self.refcnt);
}
cgroup_put(&root->cgrp);
- kernfs_kill_sb(sb);
+ kernfs_shutdown_sb(sb);
}
struct file_system_type cgroup_fs_type = {
.name = "cgroup",
.init_fs_context = cgroup_init_fs_context,
.parameters = cgroup1_fs_parameters,
- .kill_sb = cgroup_kill_sb,
+ .shutdown_sb = cgroup_shutdown_sb,
+ .free_sb = kernfs_free_sb,
.fs_flags = FS_USERNS_MOUNT,
};
@@ -2281,7 +2282,8 @@ static struct file_system_type cgroup2_fs_type = {
.name = "cgroup2",
.init_fs_context = cgroup_init_fs_context,
.parameters = cgroup2_fs_parameters,
- .kill_sb = cgroup_kill_sb,
+ .shutdown_sb = cgroup_shutdown_sb,
+ .free_sb = kernfs_free_sb,
.fs_flags = FS_USERNS_MOUNT,
};
--
2.39.2