efivarfs: move variable lifetime management into the inodes

Make the inodes the default management vehicle for struct
efivar_entry, so they are now all freed automatically if the file is
removed and on unmount in kill_litter_super().  Remove the now
superfluous iterator to free the entries after kill_litter_super().

Also fixes a bug where some entry freeing was missing causing efivarfs
to leak memory.

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>

diff --git a/fs/efivarfs/inode.c b/fs/efivarfs/inode.c
index ec23da8405ff8e1ffcfe1714a44f8119048f1f71..8f5994dea2042c4b6041f540b37b9690817cc874 100644 (file)
--- a/fs/efivarfs/inode.c
+++ b/fs/efivarfs/inode.c
@@ -82,26 +82,23 @@ static int efivarfs_create(struct mnt_idmap *idmap, struct inode *dir,
        struct efivar_entry *var;
        int namelen, i = 0, err = 0;
        bool is_removable = false;
+       efi_guid_t vendor;
 
        if (!efivarfs_valid_name(dentry->d_name.name, dentry->d_name.len))
                return -EINVAL;
 
-       var = kzalloc(sizeof(struct efivar_entry), GFP_KERNEL);
-       if (!var)
-               return -ENOMEM;
-
        /* length of the variable name itself: remove GUID and separator */
        namelen = dentry->d_name.len - EFI_VARIABLE_GUID_LEN - 1;
 
-       err = guid_parse(dentry->d_name.name + namelen + 1, &var->var.VendorGuid);
+       err = guid_parse(dentry->d_name.name + namelen + 1, &vendor);
        if (err)
                goto out;
-       if (guid_equal(&var->var.VendorGuid, &LINUX_EFI_RANDOM_SEED_TABLE_GUID)) {
+       if (guid_equal(&vendor, &LINUX_EFI_RANDOM_SEED_TABLE_GUID)) {
                err = -EPERM;
                goto out;
        }
 
-       if (efivar_variable_is_removable(var->var.VendorGuid,
+       if (efivar_variable_is_removable(vendor,
                                         dentry->d_name.name, namelen))
                is_removable = true;
 
@@ -110,6 +107,9 @@ static int efivarfs_create(struct mnt_idmap *idmap, struct inode *dir,
                err = -ENOMEM;
                goto out;
        }
+       var = efivar_entry(inode);
+
+       var->var.VendorGuid = vendor;
 
        for (i = 0; i < namelen; i++)
                var->var.VariableName[i] = dentry->d_name.name[i];
@@ -117,7 +117,6 @@ static int efivarfs_create(struct mnt_idmap *idmap, struct inode *dir,
        var->var.VariableName[i] = '\0';
 
        inode->i_private = var;
-       kmemleak_ignore(var);
 
        err = efivar_entry_add(var, &info->efivarfs_list);
        if (err)
@@ -126,11 +125,9 @@ static int efivarfs_create(struct mnt_idmap *idmap, struct inode *dir,
        d_instantiate(dentry, inode);
        dget(dentry);
 out:
-       if (err) {
-               kfree(var);
-               if (inode)
-                       iput(inode);
-       }
+       if (err && inode)
+               iput(inode);
+
        return err;
 }
 

diff --git a/fs/efivarfs/internal.h b/fs/efivarfs/internal.h
index 597ccaa60d3731eff1f4e7cf3f3c6920544aec0b..fce7d5e5c76380f96b2c4b7064c2e8086042311f 100644 (file)
--- a/fs/efivarfs/internal.h
+++ b/fs/efivarfs/internal.h
@@ -29,15 +29,20 @@ struct efi_variable {
 struct efivar_entry {
        struct efi_variable var;
        struct list_head list;
+       struct inode vfs_inode;
 };
 
+static inline struct efivar_entry *efivar_entry(struct inode *inode)
+{
+       return container_of(inode, struct efivar_entry, vfs_inode);
+}
+
 int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *,
                            struct list_head *),
                void *data, struct list_head *head);
 
 int efivar_entry_add(struct efivar_entry *entry, struct list_head *head);
 void __efivar_entry_add(struct efivar_entry *entry, struct list_head *head);
-void efivar_entry_remove(struct efivar_entry *entry);
 int efivar_entry_delete(struct efivar_entry *entry);
 
 int efivar_entry_size(struct efivar_entry *entry, unsigned long *size);

diff --git a/fs/efivarfs/super.c b/fs/efivarfs/super.c
index 9e90823f800952c442380fd76f8073a32bbbf348..85ab3af3f1e9f041387f70e566b3affd2f485da1 100644 (file)
--- a/fs/efivarfs/super.c
+++ b/fs/efivarfs/super.c
@@ -39,9 +39,25 @@ static int efivarfs_ops_notifier(struct notifier_block *nb, unsigned long event,
        return NOTIFY_OK;
 }
 
-static void efivarfs_evict_inode(struct inode *inode)
+static struct inode *efivarfs_alloc_inode(struct super_block *sb)
 {
-       clear_inode(inode);
+       struct efivar_entry *entry = kzalloc(sizeof(*entry), GFP_KERNEL);
+
+       if (!entry)
+               return NULL;
+
+       inode_init_once(&entry->vfs_inode);
+
+       return &entry->vfs_inode;
+}
+
+static void efivarfs_free_inode(struct inode *inode)
+{
+       struct efivar_entry *entry = efivar_entry(inode);
+
+       if (inode->i_private)
+               list_del(&entry->list);
+       kfree(entry);
 }
 
 static int efivarfs_show_options(struct seq_file *m, struct dentry *root)
@@ -106,7 +122,8 @@ static int efivarfs_statfs(struct dentry *dentry, struct kstatfs *buf)
 static const struct super_operations efivarfs_ops = {
        .statfs = efivarfs_statfs,
        .drop_inode = generic_delete_inode,
-       .evict_inode = efivarfs_evict_inode,
+       .alloc_inode = efivarfs_alloc_inode,
+       .free_inode = efivarfs_free_inode,
        .show_options = efivarfs_show_options,
 };
 
@@ -227,21 +244,14 @@ static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,
        if (guid_equal(&vendor, &LINUX_EFI_RANDOM_SEED_TABLE_GUID))
                return 0;
 
-       entry = kzalloc(sizeof(*entry), GFP_KERNEL);
-       if (!entry)
-               return err;
-
-       memcpy(entry->var.VariableName, name16, name_size);
-       memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
-
        name = efivar_get_utf8name(name16, &vendor);
        if (!name)
-               goto fail;
+               return err;
 
        /* length of the variable name itself: remove GUID and separator */
        len = strlen(name) - EFI_VARIABLE_GUID_LEN - 1;
 
-       if (efivar_variable_is_removable(entry->var.VendorGuid, name, len))
+       if (efivar_variable_is_removable(vendor, name, len))
                is_removable = true;
 
        inode = efivarfs_get_inode(sb, d_inode(root), S_IFREG | 0644, 0,
@@ -249,6 +259,11 @@ static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,
        if (!inode)
                goto fail_name;
 
+       entry = efivar_entry(inode);
+
+       memcpy(entry->var.VariableName, name16, name_size);
+       memcpy(&(entry->var.VendorGuid), &vendor, sizeof(efi_guid_t));
+
        dentry = efivarfs_alloc_dentry(root, name);
        if (IS_ERR(dentry)) {
                err = PTR_ERR(dentry);
@@ -273,16 +288,8 @@ fail_inode:
        iput(inode);
 fail_name:
        kfree(name);
-fail:
-       kfree(entry);
-       return err;
-}
 
-static int efivarfs_destroy(struct efivar_entry *entry, void *data)
-{
-       efivar_entry_remove(entry);
-       kfree(entry);
-       return 0;
+       return err;
 }
 
 enum {
@@ -407,7 +414,7 @@ static void efivarfs_kill_sb(struct super_block *sb)
        kill_litter_super(sb);
 
        /* Remove all entries and destroy */
-       efivar_entry_iter(efivarfs_destroy, &sfi->efivarfs_list, NULL);
+       WARN_ON(!list_empty(&sfi->efivarfs_list));
        kfree(sfi);
 }
 

diff --git a/fs/efivarfs/vars.c b/fs/efivarfs/vars.c
index b2fc5bdc759a4e03ee5a1b7e2d67fb2d8ea2b797..bb9406e03a10ef9836857ed5f79d6ddf600adcef 100644 (file)
--- a/fs/efivarfs/vars.c
+++ b/fs/efivarfs/vars.c
@@ -485,34 +485,6 @@ void __efivar_entry_add(struct efivar_entry *entry, struct list_head *head)
        list_add(&entry->list, head);
 }
 
-/**
- * efivar_entry_remove - remove entry from variable list
- * @entry: entry to remove from list
- *
- * Returns 0 on success, or a kernel error code on failure.
- */
-void efivar_entry_remove(struct efivar_entry *entry)
-{
-       list_del(&entry->list);
-}
-
-/*
- * efivar_entry_list_del_unlock - remove entry from variable list
- * @entry: entry to remove
- *
- * Remove @entry from the variable list and release the list lock.
- *
- * NOTE: slightly weird locking semantics here - we expect to be
- * called with the efivars lock already held, and we release it before
- * returning. This is because this function is usually called after
- * set_variable() while the lock is still held.
- */
-static void efivar_entry_list_del_unlock(struct efivar_entry *entry)
-{
-       list_del(&entry->list);
-       efivar_unlock();
-}
-
 /**
  * efivar_entry_delete - delete variable and remove entry from list
  * @entry: entry containing variable to delete
@@ -536,12 +508,10 @@ int efivar_entry_delete(struct efivar_entry *entry)
        status = efivar_set_variable_locked(entry->var.VariableName,
                                            &entry->var.VendorGuid,
                                            0, 0, NULL, false);
-       if (!(status == EFI_SUCCESS || status == EFI_NOT_FOUND)) {
-               efivar_unlock();
+       efivar_unlock();
+       if (!(status == EFI_SUCCESS || status == EFI_NOT_FOUND))
                return efi_status_to_err(status);
-       }
 
-       efivar_entry_list_del_unlock(entry);
        return 0;
 }
 
@@ -679,10 +649,7 @@ int efivar_entry_set_get_size(struct efivar_entry *entry, u32 attributes,
                                    &entry->var.VendorGuid,
                                    NULL, size, NULL);
 
-       if (status == EFI_NOT_FOUND)
-               efivar_entry_list_del_unlock(entry);
-       else
-               efivar_unlock();
+       efivar_unlock();
 
        if (status && status != EFI_BUFFER_TOO_SMALL)
                return efi_status_to_err(status);