From 33cabfb8a14b51eeeb713c45a722a077777eb023 Mon Sep 17 00:00:00 2001 From: Daniel Rosenberg Date: Tue, 10 May 2016 13:42:43 -0700 Subject: [PATCH] ANDROID: sdcardfs: Switch package list to RCU Switched the package id hashmap to use RCU. Change-Id: I9fdcab279009005bf28536247d11e13babab0b93 Signed-off-by: Daniel Rosenberg --- fs/sdcardfs/derived_perm.c | 3 +- fs/sdcardfs/packagelist.c | 200 +++++++++++++++++++++------------------------ fs/sdcardfs/sdcardfs.h | 2 +- 3 files changed, 93 insertions(+), 112 deletions(-) diff --git a/fs/sdcardfs/derived_perm.c b/fs/sdcardfs/derived_perm.c index bfe402b8cf32..2a75ad873a7c 100644 --- a/fs/sdcardfs/derived_perm.c +++ b/fs/sdcardfs/derived_perm.c @@ -47,7 +47,6 @@ void setup_derived_state(struct inode *inode, perm_t perm, /* While renaming, there is a point where we want the path from dentry, but the name from newdentry */ void get_derived_permission_new(struct dentry *parent, struct dentry *dentry, struct dentry *newdentry) { - struct sdcardfs_sb_info *sbi = SDCARDFS_SB(dentry->d_sb); struct sdcardfs_inode_info *info = SDCARDFS_I(dentry->d_inode); struct sdcardfs_inode_info *parent_info= SDCARDFS_I(parent->d_inode); appid_t appid; @@ -96,7 +95,7 @@ void get_derived_permission_new(struct dentry *parent, struct dentry *dentry, st case PERM_ANDROID_DATA: case PERM_ANDROID_OBB: case PERM_ANDROID_MEDIA: - appid = get_appid(sbi->pkgl_id, newdentry->d_name.name); + appid = get_appid(newdentry->d_name.name); if (appid != 0) { info->d_uid = multiuser_get_uid(parent_info->userid, appid); } diff --git a/fs/sdcardfs/packagelist.c b/fs/sdcardfs/packagelist.c index 9c3340528eee..f5a49c513568 100644 --- a/fs/sdcardfs/packagelist.c +++ b/fs/sdcardfs/packagelist.c @@ -29,26 +29,13 @@ #include -#define STRING_BUF_SIZE (512) - struct hashtable_entry { struct hlist_node hlist; - void *key; - unsigned int value; -}; - -struct sb_list { - struct super_block *sb; - struct list_head list; + const char *key; + atomic_t value; }; -struct packagelist_data { - DECLARE_HASHTABLE(package_to_appid,8); - struct mutex hashtable_lock; - -}; - -static struct packagelist_data *pkgl_data_all; +static DEFINE_HASHTABLE(package_to_appid, 8); static struct kmem_cache *hashtable_entry_cachep; @@ -64,22 +51,21 @@ static unsigned int str_hash(const char *key) { return h; } -appid_t get_appid(void *pkgl_id, const char *app_name) +appid_t get_appid(const char *app_name) { - struct packagelist_data *pkgl_dat = pkgl_data_all; struct hashtable_entry *hash_cur; unsigned int hash = str_hash(app_name); appid_t ret_id; - mutex_lock(&pkgl_dat->hashtable_lock); - hash_for_each_possible(pkgl_dat->package_to_appid, hash_cur, hlist, hash) { + rcu_read_lock(); + hash_for_each_possible_rcu(package_to_appid, hash_cur, hlist, hash) { if (!strcasecmp(app_name, hash_cur->key)) { - ret_id = (appid_t)hash_cur->value; - mutex_unlock(&pkgl_dat->hashtable_lock); + ret_id = atomic_read(&hash_cur->value); + rcu_read_unlock(); return ret_id; } } - mutex_unlock(&pkgl_dat->hashtable_lock); + rcu_read_unlock(); return 0; } @@ -120,116 +106,118 @@ int open_flags_to_access_mode(int open_flags) { } } -static int insert_str_to_int_lock(struct packagelist_data *pkgl_dat, char *key, - unsigned int value) +static struct hashtable_entry *alloc_packagelist_entry(const char *key, + appid_t value) +{ + struct hashtable_entry *ret = kmem_cache_alloc(hashtable_entry_cachep, + GFP_KERNEL); + if (!ret) + return NULL; + + ret->key = kstrdup(key, GFP_KERNEL); + if (!ret->key) { + kmem_cache_free(hashtable_entry_cachep, ret); + return NULL; + } + + atomic_set(&ret->value, value); + return ret; +} + +static int insert_packagelist_entry_locked(const char *key, appid_t value) { struct hashtable_entry *hash_cur; struct hashtable_entry *new_entry; unsigned int hash = str_hash(key); - hash_for_each_possible(pkgl_dat->package_to_appid, hash_cur, hlist, hash) { + hash_for_each_possible_rcu(package_to_appid, hash_cur, hlist, hash) { if (!strcasecmp(key, hash_cur->key)) { - hash_cur->value = value; + atomic_set(&hash_cur->value, value); return 0; } } - new_entry = kmem_cache_alloc(hashtable_entry_cachep, GFP_KERNEL); + new_entry = alloc_packagelist_entry(key, value); if (!new_entry) return -ENOMEM; - new_entry->key = kstrdup(key, GFP_KERNEL); - new_entry->value = value; - hash_add(pkgl_dat->package_to_appid, &new_entry->hlist, hash); + hash_add_rcu(package_to_appid, &new_entry->hlist, hash); return 0; } static void fixup_perms(struct super_block *sb) { if (sb && sb->s_magic == SDCARDFS_SUPER_MAGIC) { - mutex_lock(&sb->s_root->d_inode->i_mutex); get_derive_permissions_recursive(sb->s_root); - mutex_unlock(&sb->s_root->d_inode->i_mutex); } } -static int insert_str_to_int(struct packagelist_data *pkgl_dat, char *key, - unsigned int value) { - int ret; +static void fixup_all_perms(void) +{ struct sdcardfs_sb_info *sbinfo; - mutex_lock(&sdcardfs_super_list_lock); - mutex_lock(&pkgl_dat->hashtable_lock); - ret = insert_str_to_int_lock(pkgl_dat, key, value); - mutex_unlock(&pkgl_dat->hashtable_lock); - - list_for_each_entry(sbinfo, &sdcardfs_super_list, list) { - if (sbinfo) { + list_for_each_entry(sbinfo, &sdcardfs_super_list, list) + if (sbinfo) fixup_perms(sbinfo->sb); - } - } +} + +static int insert_packagelist_entry(const char *key, appid_t value) +{ + int err; + + mutex_lock(&sdcardfs_super_list_lock); + err = insert_packagelist_entry_locked(key, value); + if (!err) + fixup_all_perms(); mutex_unlock(&sdcardfs_super_list_lock); - return ret; + + return err; } -static void remove_str_to_int_lock(struct hashtable_entry *h_entry) { - kfree(h_entry->key); - hash_del(&h_entry->hlist); - kmem_cache_free(hashtable_entry_cachep, h_entry); +static void free_packagelist_entry(struct hashtable_entry *entry) +{ + kfree(entry->key); + hash_del_rcu(&entry->hlist); + kmem_cache_free(hashtable_entry_cachep, entry); } -static void remove_str_to_int(struct packagelist_data *pkgl_dat, const char *key) +static void remove_packagelist_entry_locked(const char *key) { - struct sdcardfs_sb_info *sbinfo; struct hashtable_entry *hash_cur; unsigned int hash = str_hash(key); - mutex_lock(&sdcardfs_super_list_lock); - mutex_lock(&pkgl_dat->hashtable_lock); - hash_for_each_possible(pkgl_dat->package_to_appid, hash_cur, hlist, hash) { + + hash_for_each_possible_rcu(package_to_appid, hash_cur, hlist, hash) { if (!strcasecmp(key, hash_cur->key)) { - remove_str_to_int_lock(hash_cur); - break; - } - } - mutex_unlock(&pkgl_dat->hashtable_lock); - list_for_each_entry(sbinfo, &sdcardfs_super_list, list) { - if (sbinfo) { - fixup_perms(sbinfo->sb); + hash_del_rcu(&hash_cur->hlist); + synchronize_rcu(); + free_packagelist_entry(hash_cur); + return; } } +} + +static void remove_packagelist_entry(const char *key) +{ + mutex_lock(&sdcardfs_super_list_lock); + remove_packagelist_entry_locked(key); + fixup_all_perms(); mutex_unlock(&sdcardfs_super_list_lock); return; } -static void remove_all_hashentrys(struct packagelist_data *pkgl_dat) +static void packagelist_destroy(void) { struct hashtable_entry *hash_cur; struct hlist_node *h_t; + HLIST_HEAD(free_list); int i; - mutex_lock(&pkgl_dat->hashtable_lock); - hash_for_each_safe(pkgl_dat->package_to_appid, i, h_t, hash_cur, hlist) - remove_str_to_int_lock(hash_cur); - mutex_unlock(&pkgl_dat->hashtable_lock); - hash_init(pkgl_dat->package_to_appid); -} - -static struct packagelist_data * packagelist_create(void) -{ - struct packagelist_data *pkgl_dat; + mutex_lock(&sdcardfs_super_list_lock); + hash_for_each_rcu(package_to_appid, i, hash_cur, hlist) { + hash_del_rcu(&hash_cur->hlist); + hlist_add_head(&hash_cur->hlist, &free_list); - pkgl_dat = kmalloc(sizeof(*pkgl_dat), GFP_KERNEL | __GFP_ZERO); - if (!pkgl_dat) { - printk(KERN_ERR "sdcardfs: Failed to create hash\n"); - return ERR_PTR(-ENOMEM); } - - mutex_init(&pkgl_dat->hashtable_lock); - hash_init(pkgl_dat->package_to_appid); - - return pkgl_dat; -} - -static void packagelist_destroy(struct packagelist_data *pkgl_dat) -{ - remove_all_hashentrys(pkgl_dat); + synchronize_rcu(); + hlist_for_each_entry_safe(hash_cur, h_t, &free_list, hlist) + free_packagelist_entry(hash_cur); + mutex_unlock(&sdcardfs_super_list_lock); printk(KERN_INFO "sdcardfs: destroyed packagelist pkgld\n"); - kfree(pkgl_dat); } struct package_appid { @@ -245,26 +233,21 @@ static inline struct package_appid *to_package_appid(struct config_item *item) static ssize_t package_appid_attr_show(struct config_item *item, char *page) { - ssize_t count; - count = sprintf(page, "%d\n", get_appid(pkgl_data_all, item->ci_name)); - return count; + return scnprintf(page, PAGE_SIZE, "%u\n", get_appid(item->ci_name)); } static ssize_t package_appid_attr_store(struct config_item *item, const char *page, size_t count) { struct package_appid *package_appid = to_package_appid(item); - unsigned long tmp; - char *p = (char *) page; + unsigned int tmp; int ret; - tmp = simple_strtoul(p, &p, 10); - if (!p || (*p && (*p != '\n'))) - return -EINVAL; + ret = kstrtouint(page, 10, &tmp); + if (ret) + return ret; - if (tmp > INT_MAX) - return -ERANGE; - ret = insert_str_to_int(pkgl_data_all, item->ci_name, (unsigned int)tmp); + ret = insert_packagelist_entry(item->ci_name, tmp); package_appid->add_pid = tmp; if (ret) return ret; @@ -289,7 +272,7 @@ static void package_appid_release(struct config_item *item) { printk(KERN_INFO "sdcardfs: removing %s\n", item->ci_dentry->d_name.name); /* item->ci_name is freed already, so we rely on the dentry */ - remove_str_to_int(pkgl_data_all, item->ci_dentry->d_name.name); + remove_packagelist_entry(item->ci_dentry->d_name.name); kfree(to_package_appid(item)); } @@ -333,21 +316,21 @@ static ssize_t packages_attr_show(struct config_item *item, char *page) { struct hashtable_entry *hash_cur; - struct hlist_node *h_t; int i; int count = 0, written = 0; - char errormsg[] = "\n"; + const char errormsg[] = "\n"; - mutex_lock(&pkgl_data_all->hashtable_lock); - hash_for_each_safe(pkgl_data_all->package_to_appid, i, h_t, hash_cur, hlist) { - written = scnprintf(page + count, PAGE_SIZE - sizeof(errormsg) - count, "%s %d\n", (char *)hash_cur->key, hash_cur->value); + rcu_read_lock(); + hash_for_each_rcu(package_to_appid, i, hash_cur, hlist) { + written = scnprintf(page + count, PAGE_SIZE - sizeof(errormsg) - count, "%s %d\n", + (const char *)hash_cur->key, atomic_read(&hash_cur->value)); if (count + written == PAGE_SIZE - sizeof(errormsg)) { count += scnprintf(page + count, PAGE_SIZE - count, errormsg); break; } count += written; } - mutex_unlock(&pkgl_data_all->hashtable_lock); + rcu_read_unlock(); return count; } @@ -430,7 +413,6 @@ int packagelist_init(void) return -ENOMEM; } - pkgl_data_all = packagelist_create(); configfs_sdcardfs_init(); return 0; } @@ -438,7 +420,7 @@ int packagelist_init(void) void packagelist_exit(void) { configfs_sdcardfs_exit(); - packagelist_destroy(pkgl_data_all); + packagelist_destroy(); if (hashtable_entry_cachep) kmem_cache_destroy(hashtable_entry_cachep); } diff --git a/fs/sdcardfs/sdcardfs.h b/fs/sdcardfs/sdcardfs.h index f111f898b630..75284f339ae0 100644 --- a/fs/sdcardfs/sdcardfs.h +++ b/fs/sdcardfs/sdcardfs.h @@ -396,7 +396,7 @@ extern struct mutex sdcardfs_super_list_lock; extern struct list_head sdcardfs_super_list; /* for packagelist.c */ -extern appid_t get_appid(void *pkgl_id, const char *app_name); +extern appid_t get_appid(const char *app_name); extern int check_caller_access_to_name(struct inode *parent_node, const char* name); extern int open_flags_to_access_mode(int open_flags); extern int packagelist_init(void); -- 2.11.0