From fdbfab66f3aa51b866c5d04b68ad4b69b3277a53 Mon Sep 17 00:00:00 2001 From: Daniel Rosenberg Date: Fri, 27 Jan 2017 19:35:08 -0800 Subject: [PATCH] ANDROID: sdcardfs: switch to full_name_hash and qstr Use the kernel's string hash function instead of rolling our own. Additionally, save a bit of calculation by using the qstr struct in place of strings. Change-Id: I0bbeb5ec2a9233f40135ad632e6f22c30ffa95c1 Signed-off-by: Daniel Rosenberg --- fs/sdcardfs/packagelist.c | 189 ++++++++++++++++++++++---------------- 1 file changed, 108 insertions(+), 81 deletions(-) diff --git a/fs/sdcardfs/packagelist.c b/fs/sdcardfs/packagelist.c index d7b31aad87d..dc5dc4a4b36 100644 --- a/fs/sdcardfs/packagelist.c +++ b/fs/sdcardfs/packagelist.c @@ -22,7 +22,7 @@ #include #include #include - +#include #include #include @@ -33,7 +33,7 @@ struct hashtable_entry { struct hlist_node hlist; struct hlist_node dlist; /* for deletion cleanup */ - const char *key; + struct qstr key; atomic_t value; }; @@ -44,27 +44,28 @@ static DEFINE_HASHTABLE(ext_to_groupid, 8); static struct kmem_cache *hashtable_entry_cachep; -static unsigned int str_hash(const char *key) { - int i; - unsigned int h = strlen(key); - char *data = (char *)key; +static void inline qstr_init(struct qstr *q, const char *name) { + q->name = name; + q->len = strlen(q->name); + q->hash = full_name_hash(q->name, q->len); +} - for (i = 0; i < strlen(key); i++) { - h = h * 31 + *data; - data++; - } - return h; +static inline int qstr_copy(const struct qstr *src, struct qstr *dest) { + dest->name = kstrdup(src->name, GFP_KERNEL); + dest->hash_len = src->hash_len; + return !!dest->name; } -appid_t get_appid(const char *key) + +static appid_t __get_appid(const struct qstr *key) { struct hashtable_entry *hash_cur; - unsigned int hash = str_hash(key); + unsigned int hash = key->hash; appid_t ret_id; rcu_read_lock(); hash_for_each_possible_rcu(package_to_appid, hash_cur, hlist, hash) { - if (!strcasecmp(key, hash_cur->key)) { + if (!strcasecmp(key->name, hash_cur->key.name)) { ret_id = atomic_read(&hash_cur->value); rcu_read_unlock(); return ret_id; @@ -74,15 +75,22 @@ appid_t get_appid(const char *key) return 0; } -appid_t get_ext_gid(const char *key) +appid_t get_appid(const char *key) +{ + struct qstr q; + qstr_init(&q, key); + return __get_appid(&q); +} + +static appid_t __get_ext_gid(const struct qstr *key) { struct hashtable_entry *hash_cur; - unsigned int hash = str_hash(key); + unsigned int hash = key->hash; appid_t ret_id; rcu_read_lock(); hash_for_each_possible_rcu(ext_to_groupid, hash_cur, hlist, hash) { - if (!strcasecmp(key, hash_cur->key)) { + if (!strcasecmp(key->name, hash_cur->key.name)) { ret_id = atomic_read(&hash_cur->value); rcu_read_unlock(); return ret_id; @@ -92,14 +100,22 @@ appid_t get_ext_gid(const char *key) return 0; } -appid_t is_excluded(const char *app_name, userid_t user) +appid_t get_ext_gid(const char *key) +{ + struct qstr q; + qstr_init(&q, key); + return __get_ext_gid(&q); +} + +static appid_t __is_excluded(const struct qstr *app_name, userid_t user) { struct hashtable_entry *hash_cur; - unsigned int hash = str_hash(app_name); + unsigned int hash = app_name->hash; rcu_read_lock(); hash_for_each_possible_rcu(package_to_userid, hash_cur, hlist, hash) { - if (atomic_read(&hash_cur->value) == user && !strcasecmp(app_name, hash_cur->key)) { + if (atomic_read(&hash_cur->value) == user && + !strcasecmp(app_name->name, hash_cur->key.name)) { rcu_read_unlock(); return 1; } @@ -108,6 +124,14 @@ appid_t is_excluded(const char *app_name, userid_t user) return 0; } +appid_t is_excluded(const char *app_name, userid_t user) +{ + struct qstr q; + qstr_init(&q, app_name); + return __is_excluded(&q, user); +} + + /* Kernel has already enforced everything we returned through * derive_permissions_locked(), so this is used to lock down access * even further, such as enforcing that apps hold sdcard_rw. */ @@ -145,7 +169,7 @@ int open_flags_to_access_mode(int open_flags) { } } -static struct hashtable_entry *alloc_hashtable_entry(const char *key, +static struct hashtable_entry *alloc_hashtable_entry(const struct qstr *key, appid_t value) { struct hashtable_entry *ret = kmem_cache_alloc(hashtable_entry_cachep, @@ -153,8 +177,7 @@ static struct hashtable_entry *alloc_hashtable_entry(const char *key, if (!ret) return NULL; - ret->key = kstrdup(key, GFP_KERNEL); - if (!ret->key) { + if (!qstr_copy(key, &ret->key)) { kmem_cache_free(hashtable_entry_cachep, ret); return NULL; } @@ -163,14 +186,14 @@ static struct hashtable_entry *alloc_hashtable_entry(const char *key, return ret; } -static int insert_packagelist_appid_entry_locked(const char *key, appid_t value) +static int insert_packagelist_appid_entry_locked(const struct qstr *key, appid_t value) { struct hashtable_entry *hash_cur; struct hashtable_entry *new_entry; - unsigned int hash = str_hash(key); + unsigned int hash = key->hash; hash_for_each_possible_rcu(package_to_appid, hash_cur, hlist, hash) { - if (!strcasecmp(key, hash_cur->key)) { + if (!strcasecmp(key->name, hash_cur->key.name)) { atomic_set(&hash_cur->value, value); return 0; } @@ -182,15 +205,15 @@ static int insert_packagelist_appid_entry_locked(const char *key, appid_t value) return 0; } -static int insert_ext_gid_entry_locked(const char *key, appid_t value) +static int insert_ext_gid_entry_locked(const struct qstr *key, appid_t value) { struct hashtable_entry *hash_cur; struct hashtable_entry *new_entry; - unsigned int hash = str_hash(key); + unsigned int hash = key->hash; /* An extension can only belong to one gid */ hash_for_each_possible_rcu(ext_to_groupid, hash_cur, hlist, hash) { - if (!strcasecmp(key, hash_cur->key)) + if (!strcasecmp(key->name, hash_cur->key.name)) return -EINVAL; } new_entry = alloc_hashtable_entry(key, value); @@ -200,15 +223,16 @@ static int insert_ext_gid_entry_locked(const char *key, appid_t value) return 0; } -static int insert_userid_exclude_entry_locked(const char *key, userid_t value) +static int insert_userid_exclude_entry_locked(const struct qstr *key, userid_t value) { struct hashtable_entry *hash_cur; struct hashtable_entry *new_entry; - unsigned int hash = str_hash(key); + unsigned int hash = key->hash; /* Only insert if not already present */ hash_for_each_possible_rcu(package_to_userid, hash_cur, hlist, hash) { - if (atomic_read(&hash_cur->value) == value && !strcasecmp(key, hash_cur->key)) + if (atomic_read(&hash_cur->value) == value && + !strcasecmp(key->name, hash_cur->key.name)) return 0; } new_entry = alloc_hashtable_entry(key, value); @@ -218,13 +242,13 @@ static int insert_userid_exclude_entry_locked(const char *key, userid_t value) return 0; } -static void fixup_all_perms_name(const char *key) +static void fixup_all_perms_name(const struct qstr *key) { struct sdcardfs_sb_info *sbinfo; struct limit_search limit = { .flags = BY_NAME, - .name = key, - .length = strlen(key), + .name = key->name, + .length = key->len, }; list_for_each_entry(sbinfo, &sdcardfs_super_list, list) { if (sbinfo_has_sdcard_magic(sbinfo)) @@ -232,13 +256,13 @@ static void fixup_all_perms_name(const char *key) } } -static void fixup_all_perms_name_userid(const char *key, userid_t userid) +static void fixup_all_perms_name_userid(const struct qstr *key, userid_t userid) { struct sdcardfs_sb_info *sbinfo; struct limit_search limit = { .flags = BY_NAME | BY_USERID, - .name = key, - .length = strlen(key), + .name = key->name, + .length = key->len, .userid = userid, }; list_for_each_entry(sbinfo, &sdcardfs_super_list, list) { @@ -260,7 +284,7 @@ static void fixup_all_perms_userid(userid_t userid) } } -static int insert_packagelist_entry(const char *key, appid_t value) +static int insert_packagelist_entry(const struct qstr *key, appid_t value) { int err; @@ -273,7 +297,7 @@ static int insert_packagelist_entry(const char *key, appid_t value) return err; } -static int insert_ext_gid_entry(const char *key, appid_t value) +static int insert_ext_gid_entry(const struct qstr *key, appid_t value) { int err; @@ -284,7 +308,7 @@ static int insert_ext_gid_entry(const char *key, appid_t value) return err; } -static int insert_userid_exclude_entry(const char *key, userid_t value) +static int insert_userid_exclude_entry(const struct qstr *key, userid_t value) { int err; @@ -299,26 +323,26 @@ static int insert_userid_exclude_entry(const char *key, userid_t value) static void free_hashtable_entry(struct hashtable_entry *entry) { - kfree(entry->key); + kfree(entry->key.name); hash_del_rcu(&entry->dlist); kmem_cache_free(hashtable_entry_cachep, entry); } -static void remove_packagelist_entry_locked(const char *key) +static void remove_packagelist_entry_locked(const struct qstr *key) { struct hashtable_entry *hash_cur; - unsigned int hash = str_hash(key); + unsigned int hash = key->hash; struct hlist_node *h_t; HLIST_HEAD(free_list); hash_for_each_possible_rcu(package_to_userid, hash_cur, hlist, hash) { - if (!strcasecmp(key, hash_cur->key)) { + if (!strcasecmp(key->name, hash_cur->key.name)) { hash_del_rcu(&hash_cur->hlist); hlist_add_head(&hash_cur->dlist, &free_list); } } hash_for_each_possible_rcu(package_to_appid, hash_cur, hlist, hash) { - if (!strcasecmp(key, hash_cur->key)) { + if (!strcasecmp(key->name, hash_cur->key.name)) { hash_del_rcu(&hash_cur->hlist); hlist_add_head(&hash_cur->dlist, &free_list); break; @@ -329,7 +353,7 @@ static void remove_packagelist_entry_locked(const char *key) free_hashtable_entry(hash_cur); } -static void remove_packagelist_entry(const char *key) +static void remove_packagelist_entry(const struct qstr *key) { mutex_lock(&sdcardfs_super_list_lock); remove_packagelist_entry_locked(key); @@ -338,13 +362,13 @@ static void remove_packagelist_entry(const char *key) return; } -static void remove_ext_gid_entry_locked(const char *key, gid_t group) +static void remove_ext_gid_entry_locked(const struct qstr *key, gid_t group) { struct hashtable_entry *hash_cur; - unsigned int hash = str_hash(key); + unsigned int hash = key->hash; hash_for_each_possible_rcu(ext_to_groupid, hash_cur, hlist, hash) { - if (!strcasecmp(key, hash_cur->key) && atomic_read(&hash_cur->value) == group) { + if (!strcasecmp(key->name, hash_cur->key.name) && atomic_read(&hash_cur->value) == group) { hash_del_rcu(&hash_cur->hlist); synchronize_rcu(); free_hashtable_entry(hash_cur); @@ -353,7 +377,7 @@ static void remove_ext_gid_entry_locked(const char *key, gid_t group) } } -static void remove_ext_gid_entry(const char *key, gid_t group) +static void remove_ext_gid_entry(const struct qstr *key, gid_t group) { mutex_lock(&sdcardfs_super_list_lock); remove_ext_gid_entry_locked(key, group); @@ -389,13 +413,14 @@ static void remove_userid_all_entry(userid_t userid) return; } -static void remove_userid_exclude_entry_locked(const char *key, userid_t userid) +static void remove_userid_exclude_entry_locked(const struct qstr *key, userid_t userid) { struct hashtable_entry *hash_cur; - unsigned int hash = str_hash(key); + unsigned int hash = key->hash; hash_for_each_possible_rcu(package_to_userid, hash_cur, hlist, hash) { - if (!strcasecmp(key, hash_cur->key) && atomic_read(&hash_cur->value) == userid) { + if (!strcasecmp(key->name, hash_cur->key.name) && + atomic_read(&hash_cur->value) == userid) { hash_del_rcu(&hash_cur->hlist); synchronize_rcu(); free_hashtable_entry(hash_cur); @@ -404,7 +429,7 @@ static void remove_userid_exclude_entry_locked(const char *key, userid_t userid) } } -static void remove_userid_exclude_entry(const char *key, userid_t userid) +static void remove_userid_exclude_entry(const struct qstr *key, userid_t userid) { mutex_lock(&sdcardfs_super_list_lock); remove_userid_exclude_entry_locked(key, userid); @@ -437,7 +462,7 @@ static void packagelist_destroy(void) struct package_details { struct config_item item; - const char* name; + struct qstr name; }; static inline struct package_details *to_package_details(struct config_item *item) @@ -453,7 +478,7 @@ struct package_details_attribute package_details_attr_##_name = __CONFIGFS_ATTR( static ssize_t package_details_appid_show(struct package_details *package_details, char *page) { - return scnprintf(page, PAGE_SIZE, "%u\n", get_appid(package_details->name)); + return scnprintf(page, PAGE_SIZE, "%u\n", __get_appid(&package_details->name)); } static ssize_t package_details_appid_store(struct package_details *package_details, @@ -466,7 +491,7 @@ static ssize_t package_details_appid_store(struct package_details *package_detai if (ret) return ret; - ret = insert_packagelist_entry(package_details->name, tmp); + ret = insert_packagelist_entry(&package_details->name, tmp); if (ret) return ret; @@ -478,12 +503,12 @@ static ssize_t package_details_excluded_userids_show(struct package_details *pac char *page) { struct hashtable_entry *hash_cur; - unsigned int hash = str_hash(package_details->name); + unsigned int hash = package_details->name.hash; int count = 0; rcu_read_lock(); hash_for_each_possible_rcu(package_to_userid, hash_cur, hlist, hash) { - if (!strcasecmp(package_details->name, hash_cur->key)) + if (!strcasecmp(package_details->name.name, hash_cur->key.name)) count += scnprintf(page + count, PAGE_SIZE - count, "%d ", atomic_read(&hash_cur->value)); } @@ -504,7 +529,7 @@ static ssize_t package_details_excluded_userids_store(struct package_details *pa if (ret) return ret; - ret = insert_userid_exclude_entry(package_details->name, tmp); + ret = insert_userid_exclude_entry(&package_details->name, tmp); if (ret) return ret; @@ -521,16 +546,16 @@ static ssize_t package_details_clear_userid_store(struct package_details *packag ret = kstrtouint(page, 10, &tmp); if (ret) return ret; - remove_userid_exclude_entry(package_details->name, tmp); + remove_userid_exclude_entry(&package_details->name, tmp); return count; } static void package_details_release(struct config_item *item) { struct package_details *package_details = to_package_details(item); - printk(KERN_INFO "sdcardfs: removing %s\n", package_details->name); - remove_packagelist_entry(package_details->name); - kfree(package_details->name); + printk(KERN_INFO "sdcardfs: removing %s\n", package_details->name.name); + remove_packagelist_entry(&package_details->name); + kfree(package_details->name.name); kfree(package_details); } @@ -567,7 +592,7 @@ struct extensions_value { struct extension_details { struct config_item item; - const char* name; + struct qstr name; unsigned int num; }; @@ -586,9 +611,9 @@ static void extension_details_release(struct config_item *item) struct extension_details *extension_details = to_extension_details(item); printk(KERN_INFO "sdcardfs: No longer mapping %s files to gid %d\n", - extension_details->name, extension_details->num); - remove_ext_gid_entry(extension_details->name, extension_details->num); - kfree(extension_details->name); + extension_details->name.name, extension_details->num); + remove_ext_gid_entry(&extension_details->name, extension_details->num); + kfree(extension_details->name.name); kfree(extension_details); } @@ -605,20 +630,21 @@ static struct config_item *extension_details_make_item(struct config_group *grou { struct extensions_value *extensions_value = to_extensions_value(&group->cg_item); struct extension_details *extension_details = kzalloc(sizeof(struct extension_details), GFP_KERNEL); + const char *tmp; int ret; if (!extension_details) return ERR_PTR(-ENOMEM); - extension_details->name = kstrdup(name, GFP_KERNEL); - if (!extension_details->name) { + tmp = kstrdup(name, GFP_KERNEL); + if (!tmp) { kfree(extension_details); return ERR_PTR(-ENOMEM); } - extension_details->num = extensions_value->num; - ret = insert_ext_gid_entry(name, extensions_value->num); + qstr_init(&extension_details->name, tmp); + ret = insert_ext_gid_entry(&extension_details->name, extensions_value->num); if (ret) { - kfree(extension_details->name); + kfree(extension_details->name.name); kfree(extension_details); return ERR_PTR(ret); } @@ -699,16 +725,17 @@ struct packages_attribute packages_attr_##_name = __CONFIGFS_ATTR_RO(_name, _sho static struct config_item *packages_make_item(struct config_group *group, const char *name) { struct package_details *package_details; + const char *tmp; package_details = kzalloc(sizeof(struct package_details), GFP_KERNEL); if (!package_details) return ERR_PTR(-ENOMEM); - package_details->name = kstrdup(name, GFP_KERNEL); - if (!package_details->name) { + tmp = kstrdup(name, GFP_KERNEL); + if (!tmp) { kfree(package_details); return ERR_PTR(-ENOMEM); } - + qstr_init(&package_details->name, tmp); config_item_init_type_name(&package_details->item, name, &package_appid_type); @@ -728,13 +755,13 @@ static ssize_t packages_list_show(struct packages *packages, rcu_read_lock(); hash_for_each_rcu(package_to_appid, i, hash_cur_app, hlist) { written = scnprintf(page + count, PAGE_SIZE - sizeof(errormsg) - count, "%s %d\n", - hash_cur_app->key, atomic_read(&hash_cur_app->value)); - hash = str_hash(hash_cur_app->key); + hash_cur_app->key.name, atomic_read(&hash_cur_app->value)); + hash = hash_cur_app->key.hash; hash_for_each_possible_rcu(package_to_userid, hash_cur_user, hlist, hash) { - if (!strcasecmp(hash_cur_app->key, hash_cur_user->key)) { + if (!strcasecmp(hash_cur_app->key.name, hash_cur_user->key.name)) { written += scnprintf(page + count + written - 1, PAGE_SIZE - sizeof(errormsg) - count - written + 1, - " %d\n", atomic_read(&hash_cur_user->value)) - 1; + " %d\n", atomic_read(&hash_cur_user->value)) - 1; } } if (count + written == PAGE_SIZE - sizeof(errormsg) - 1) { -- 2.20.1