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Subject[PATCH v3 5/9] efi: vars: Use locking version to iterate over efivars linked lists
Date
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>
---
drivers/firmware/efi/efivars.c | 8 ++------
drivers/firmware/efi/vars.c | 9 +--------
fs/efivarfs/super.c | 9 +++------
include/linux/efi.h | 2 +-
4 files changed, 7 insertions(+), 21 deletions(-)

diff --git a/drivers/firmware/efi/efivars.c b/drivers/firmware/efi/efivars.c
index 8341fb15f62e..801a65582172 100644
--- a/drivers/firmware/efi/efivars.c
+++ b/drivers/firmware/efi/efivars.c
@@ -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;
diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c
index 5640ffa81544..29540013b358 100644
--- a/drivers/firmware/efi/vars.c
+++ b/drivers/firmware/efi/vars.c
@@ -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);

diff --git a/fs/efivarfs/super.c b/fs/efivarfs/super.c
index 09dfa8362f50..6780fc81cc11 100644
--- a/fs/efivarfs/super.c
+++ b/fs/efivarfs/super.c
@@ -180,10 +180,7 @@ static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor,

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 = {
diff --git a/include/linux/efi.h b/include/linux/efi.h
index 08bc6215e3b4..54ca2d6b6c78 100644
--- a/include/linux/efi.h
+++ b/include/linux/efi.h
@@ -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);
--
2.35.1
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