[PATCH 6.7 309/713] pstore: inode: Convert mutex usage to guard(mutex)

Sasha Levin
2024-03-24T22:52:25Z

From: Kees Cook <keescook@chromium.org>

[ Upstream commit e2eeddefb046dbc771a6fa426f7f98fb25adfe68 ]

Replace open-coded mutex handling with cleanup.h guard(mutex) and
scoped_guard(mutex, ...).

Cc: Guilherme G. Piccoli <gpiccoli@igalia.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: <linux-hardening@vger.kernel.org>
Link: https://lore.kernel.org/r/20231205182622.1329923-2-keescook@chromium.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Stable-dep-of: a43e0fc5e913 ("pstore: inode: Only d_invalidate() is needed")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/pstore/inode.c | 76 +++++++++++++++++++----------------------------
1 file changed, 31 insertions(+), 45 deletions(-)

diff --git a/fs/pstore/inode.c b/fs/pstore/inode.c
index d41c20d1b5e82..4b4686c593996 100644
--- a/fs/pstore/inode.c
+++ b/fs/pstore/inode.c
@@ -182,25 +182,21 @@ static int pstore_unlink(struct inode *dir, struct dentry *dentry)
{
struct pstore_private *p = d_inode(dentry)->i_private;
struct pstore_record *record = p->record;
- int rc = 0;

if (!record->psi->erase)
return -EPERM;

/* Make sure we can't race while removing this file. */
- mutex_lock(&records_list_lock);
- if (!list_empty(&p->list))
- list_del_init(&p->list);
- else
- rc = -ENOENT;
- p->dentry = NULL;
- mutex_unlock(&records_list_lock);
- if (rc)
- return rc;
-
- mutex_lock(&record->psi->read_mutex);
- record->psi->erase(record);
- mutex_unlock(&record->psi->read_mutex);
+ scoped_guard(mutex, &records_list_lock) {
+ if (!list_empty(&p->list))
+ list_del_init(&p->list);
+ else
+ return -ENOENT;
+ p->dentry = NULL;
+ }
+
+ scoped_guard(mutex, &record->psi->read_mutex)
+ record->psi->erase(record);

return simple_unlink(dir, dentry);
}
@@ -292,19 +288,16 @@ static struct dentry *psinfo_lock_root(void)
{
struct dentry *root;

- mutex_lock(&pstore_sb_lock);
+ guard(mutex)(&pstore_sb_lock);
/*
* Having no backend is fine -- no records appear.
* Not being mounted is fine -- nothing to do.
*/
- if (!psinfo || !pstore_sb) {
- mutex_unlock(&pstore_sb_lock);
+ if (!psinfo || !pstore_sb)
return NULL;
- }

root = pstore_sb->s_root;
inode_lock(d_inode(root));
- mutex_unlock(&pstore_sb_lock);

return root;
}
@@ -319,19 +312,19 @@ int pstore_put_backend_records(struct pstore_info *psi)
if (!root)
return 0;

- mutex_lock(&records_list_lock);
- list_for_each_entry_safe(pos, tmp, &records_list, list) {
- if (pos->record->psi == psi) {
- list_del_init(&pos->list);
- rc = simple_unlink(d_inode(root), pos->dentry);
- if (WARN_ON(rc))
- break;
- d_drop(pos->dentry);
- dput(pos->dentry);
- pos->dentry = NULL;
+ scoped_guard(mutex, &records_list_lock) {
+ list_for_each_entry_safe(pos, tmp, &records_list, list) {
+ if (pos->record->psi == psi) {
+ list_del_init(&pos->list);
+ rc = simple_unlink(d_inode(root), pos->dentry);
+ if (WARN_ON(rc))
+ break;
+ d_drop(pos->dentry);
+ dput(pos->dentry);
+ pos->dentry = NULL;
+ }
}
}
- mutex_unlock(&records_list_lock);

inode_unlock(d_inode(root));

@@ -355,20 +348,20 @@ int pstore_mkfile(struct dentry *root, struct pstore_record *record)
if (WARN_ON(!inode_is_locked(d_inode(root))))
return -EINVAL;

- rc = -EEXIST;
+ guard(mutex)(&records_list_lock);
+
/* Skip records that are already present in the filesystem. */
- mutex_lock(&records_list_lock);
list_for_each_entry(pos, &records_list, list) {
if (pos->record->type == record->type &&
pos->record->id == record->id &&
pos->record->psi == record->psi)
- goto fail;
+ return -EEXIST;
}

rc = -ENOMEM;
inode = pstore_get_inode(root->d_sb);
if (!inode)
- goto fail;
+ return -ENOMEM;
inode->i_mode = S_IFREG | 0444;
inode->i_fop = &pstore_file_operations;
scnprintf(name, sizeof(name), "%s-%s-%llu%s",
@@ -396,7 +389,6 @@ int pstore_mkfile(struct dentry *root, struct pstore_record *record)
d_add(dentry, inode);

list_add(&private->list, &records_list);
- mutex_unlock(&records_list_lock);

return 0;

@@ -404,8 +396,6 @@ int pstore_mkfile(struct dentry *root, struct pstore_record *record)
free_pstore_private(private);
fail_inode:
iput(inode);
-fail:
- mutex_unlock(&records_list_lock);
return rc;
}

@@ -451,9 +441,8 @@ static int pstore_fill_super(struct super_block *sb, void *data, int silent)
if (!sb->s_root)
return -ENOMEM;

- mutex_lock(&pstore_sb_lock);
- pstore_sb = sb;
- mutex_unlock(&pstore_sb_lock);
+ scoped_guard(mutex, &pstore_sb_lock)
+ pstore_sb = sb;

pstore_get_records(0);

@@ -468,17 +457,14 @@ static struct dentry *pstore_mount(struct file_system_type *fs_type,

static void pstore_kill_sb(struct super_block *sb)
{
- mutex_lock(&pstore_sb_lock);
+ guard(mutex)(&pstore_sb_lock);
WARN_ON(pstore_sb && pstore_sb != sb);

kill_litter_super(sb);
pstore_sb = NULL;

- mutex_lock(&records_list_lock);
+ guard(mutex)(&records_list_lock);
INIT_LIST_HEAD(&records_list);
- mutex_unlock(&records_list_lock);
-
- mutex_unlock(&pstore_sb_lock);
}

static struct file_system_type pstore_fs_type = {
--
2.43.0