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efi: vars: Use locking version to iterate over efivars linked lists

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Both efivars and efivarfs uses __efivar_entry_iter() to go over the
linked list that shadows the list of EFI variables held by the firmware,
but fail to call the begin/end helpers that are documented as a
prerequisite.

So switch to the proper version, which is efivar_entry_iter(). Given
that in both cases, efivar_entry_remove() is invoked with the lock held
already, don't take the lock there anymore.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
This commit is contained in:
Ard Biesheuvel 2022-06-21 15:48:29 +02:00
parent 859748255b
commit 3a75f9f2f9
4 changed files with 7 additions and 21 deletions
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8
drivers/firmware/efi/efivars.c
View File

@ -602,10 +602,7 @@ static int efivars_sysfs_callback(efi_char16_t *name, efi_guid_t vendor,
static int efivar_sysfs_destroy(struct efivar_entry *entry, void *data)
{
int err = efivar_entry_remove(entry);
if (err)
return err;
efivar_entry_remove(entry);
efivar_unregister(entry);
return 0;
}
@ -615,8 +612,7 @@ static void efivars_sysfs_exit(void)
/* Remove all entries and destroy */
int err;
err = __efivar_entry_iter(efivar_sysfs_destroy, &efivar_sysfs_list,
NULL, NULL);
err = efivar_entry_iter(efivar_sysfs_destroy, &efivar_sysfs_list, NULL);
if (err) {
pr_err("efivars: Failed to destroy sysfs entries\n");
return;

9
drivers/firmware/efi/vars.c
View File

@ -523,17 +523,10 @@ EXPORT_SYMBOL_GPL(__efivar_entry_add);
/**
* 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.
*/
int efivar_entry_remove(struct efivar_entry *entry)
void efivar_entry_remove(struct efivar_entry *entry)
{
if (down_interruptible(&efivars_lock))
return -EINTR;
list_del(&entry->list);
up(&efivars_lock);
return 0;
}
EXPORT_SYMBOL_GPL(efivar_entry_remove);

9
fs/efivarfs/super.c
View File

@ -180,10 +180,7 @@ fail:
static int efivarfs_destroy(struct efivar_entry *entry, void *data)
{
int err = efivar_entry_remove(entry);
if (err)
return err;
efivar_entry_remove(entry);
kfree(entry);
return 0;
}
@ -219,7 +216,7 @@ static int efivarfs_fill_super(struct super_block *sb, struct fs_context *fc)
err = efivar_init(efivarfs_callback, (void *)sb, true, &efivarfs_list);
if (err)
__efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL, NULL);
efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL);
return err;
}
@ -244,7 +241,7 @@ static void efivarfs_kill_sb(struct super_block *sb)
kill_litter_super(sb);
/* Remove all entries and destroy */
__efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL, NULL);
efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL);
}
static struct file_system_type efivarfs_type = {

2
include/linux/efi.h
View File

@ -1063,7 +1063,7 @@ int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *),
int efivar_entry_add(struct efivar_entry *entry, struct list_head *head);
void __efivar_entry_add(struct efivar_entry *entry, struct list_head *head);
int efivar_entry_remove(struct efivar_entry *entry);
void efivar_entry_remove(struct efivar_entry *entry);
int __efivar_entry_delete(struct efivar_entry *entry);
int efivar_entry_delete(struct efivar_entry *entry);