1 files changed, 165 insertions, 93 deletions

diff --git a/drivers/firmware/efi/vars.c b/drivers/firmware/efi/vars.c
index cae590bd08f2..932435945c85 100644
--- a/drivers/firmware/efi/vars.c
+++ b/drivers/firmware/efi/vars.c
@@ -298,14 +298,10 @@ efivar_variable_is_removable(efi_guid_t vendor, const char *var_name,
 }
 EXPORT_SYMBOL_GPL(efivar_variable_is_removable);
 
-static efi_status_t
-check_var_size(u32 attributes, unsigned long size)
+efi_status_t check_var_size(u32 attributes, unsigned long size)
 {
 	const struct efivar_operations *fops;
 
-	if (!__efivars)
-		return EFI_UNSUPPORTED;
-
 	fops = __efivars->ops;
 
 	if (!fops->query_variable_store)
@@ -313,15 +309,12 @@ check_var_size(u32 attributes, unsigned long size)
 
 	return fops->query_variable_store(attributes, size, false);
 }
+EXPORT_SYMBOL_NS_GPL(check_var_size, EFIVAR);
 
-static efi_status_t
-check_var_size_nonblocking(u32 attributes, unsigned long size)
+efi_status_t check_var_size_nonblocking(u32 attributes, unsigned long size)
 {
 	const struct efivar_operations *fops;
 
-	if (!__efivars)
-		return EFI_UNSUPPORTED;
-
 	fops = __efivars->ops;
 
 	if (!fops->query_variable_store)
@@ -329,6 +322,7 @@ check_var_size_nonblocking(u32 attributes, unsigned long size)
 
 	return fops->query_variable_store(attributes, size, true);
 }
+EXPORT_SYMBOL_NS_GPL(check_var_size_nonblocking, EFIVAR);
 
 static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor,
 				struct list_head *head)
@@ -450,9 +444,6 @@ int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *),
 						&vendor_guid);
 		switch (status) {
 		case EFI_SUCCESS:
-			if (duplicates)
-				up(&efivars_lock);
-
 			variable_name_size = var_name_strnsize(variable_name,
 							       variable_name_size);
 
@@ -476,14 +467,6 @@ int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *),
 				if (err)
 					status = EFI_NOT_FOUND;
 			}
-
-			if (duplicates) {
-				if (down_interruptible(&efivars_lock)) {
-					err = -EINTR;
-					goto free;
-				}
-			}
-
 			break;
 		case EFI_UNSUPPORTED:
 			err = -EOPNOTSUPP;
@@ -527,19 +510,23 @@ int efivar_entry_add(struct efivar_entry *entry, struct list_head *head)
 EXPORT_SYMBOL_GPL(efivar_entry_add);
 
 /**
+ * __efivar_entry_add - add entry to variable list
+ * @entry: entry to add to list
+ * @head: list head
+ */
+void __efivar_entry_add(struct efivar_entry *entry, struct list_head *head)
+{
+	list_add(&entry->list, head);
+}
+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);
 
@@ -827,16 +814,8 @@ struct efivar_entry *efivar_entry_find(efi_char16_t *name, efi_guid_t guid,
 	if (!found)
 		return NULL;
 
-	if (remove) {
-		if (entry->scanning) {
-			/*
-			 * The entry will be deleted
-			 * after scanning is completed.
-			 */
-			entry->deleting = true;
-		} else
-			list_del(&entry->list);
-	}
+	if (remove)
+		list_del(&entry->list);
 
 	return entry;
 }
@@ -1056,59 +1035,6 @@ void efivar_entry_iter_end(void)
 EXPORT_SYMBOL_GPL(efivar_entry_iter_end);
 
 /**
- * __efivar_entry_iter - iterate over variable list
- * @func: callback function
- * @head: head of the variable list
- * @data: function-specific data to pass to callback
- * @prev: entry to begin iterating from
- *
- * Iterate over the list of EFI variables and call @func with every
- * entry on the list. It is safe for @func to remove entries in the
- * list via efivar_entry_delete().
- *
- * You MUST call efivar_entry_iter_begin() before this function, and
- * efivar_entry_iter_end() afterwards.
- *
- * It is possible to begin iteration from an arbitrary entry within
- * the list by passing @prev. @prev is updated on return to point to
- * the last entry passed to @func. To begin iterating from the
- * beginning of the list @prev must be %NULL.
- *
- * The restrictions for @func are the same as documented for
- * efivar_entry_iter().
- */
-int __efivar_entry_iter(int (*func)(struct efivar_entry *, void *),
-			struct list_head *head, void *data,
-			struct efivar_entry **prev)
-{
-	struct efivar_entry *entry, *n;
-	int err = 0;
-
-	if (!prev || !*prev) {
-		list_for_each_entry_safe(entry, n, head, list) {
-			err = func(entry, data);
-			if (err)
-				break;
-		}
-
-		if (prev)
-			*prev = entry;
-
-		return err;
-	}
-
-
-	list_for_each_entry_safe_continue((*prev), n, head, list) {
-		err = func(*prev, data);
-		if (err)
-			break;
-	}
-
-	return err;
-}
-EXPORT_SYMBOL_GPL(__efivar_entry_iter);
-
-/**
  * efivar_entry_iter - iterate over variable list
  * @func: callback function
  * @head: head of variable list
@@ -1125,12 +1051,18 @@ EXPORT_SYMBOL_GPL(__efivar_entry_iter);
 int efivar_entry_iter(int (*func)(struct efivar_entry *, void *),
 		      struct list_head *head, void *data)
 {
+	struct efivar_entry *entry, *n;
 	int err = 0;
 
 	err = efivar_entry_iter_begin();
 	if (err)
 		return err;
-	err = __efivar_entry_iter(func, head, data, NULL);
+
+	list_for_each_entry_safe(entry, n, head, list) {
+		err = func(entry, data);
+		if (err)
+			break;
+	}
 	efivar_entry_iter_end();
 
 	return err;
@@ -1220,3 +1152,143 @@ int efivar_supports_writes(void)
 	return __efivars && __efivars->ops->set_variable;
 }
 EXPORT_SYMBOL_GPL(efivar_supports_writes);
+
+/*
+ * efivar_lock() - obtain the efivar lock, wait for it if needed
+ * @return 0 on success, error code on failure
+ */
+int efivar_lock(void)
+{
+	if (down_interruptible(&efivars_lock))
+		return -EINTR;
+	if (!__efivars->ops) {
+		up(&efivars_lock);
+		return -ENODEV;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_NS_GPL(efivar_lock, EFIVAR);
+
+/*
+ * efivar_lock() - obtain the efivar lock if it is free
+ * @return 0 on success, error code on failure
+ */
+int efivar_trylock(void)
+{
+	if (down_trylock(&efivars_lock))
+		 return -EBUSY;
+	if (!__efivars->ops) {
+		up(&efivars_lock);
+		return -ENODEV;
+	}
+	return 0;
+}
+EXPORT_SYMBOL_NS_GPL(efivar_trylock, EFIVAR);
+
+/*
+ * efivar_unlock() - release the efivar lock
+ */
+void efivar_unlock(void)
+{
+	up(&efivars_lock);
+}
+EXPORT_SYMBOL_NS_GPL(efivar_unlock, EFIVAR);
+
+/*
+ * efivar_get_variable() - retrieve a variable identified by name/vendor
+ *
+ * Must be called with efivars_lock held.
+ */
+efi_status_t efivar_get_variable(efi_char16_t *name, efi_guid_t *vendor,
+				 u32 *attr, unsigned long *size, void *data)
+{
+	return __efivars->ops->get_variable(name, vendor, attr, size, data);
+}
+EXPORT_SYMBOL_NS_GPL(efivar_get_variable, EFIVAR);
+
+/*
+ * efivar_get_next_variable() - enumerate the next name/vendor pair
+ *
+ * Must be called with efivars_lock held.
+ */
+efi_status_t efivar_get_next_variable(unsigned long *name_size,
+				      efi_char16_t *name, efi_guid_t *vendor)
+{
+	return __efivars->ops->get_next_variable(name_size, name, vendor);
+}
+EXPORT_SYMBOL_NS_GPL(efivar_get_next_variable, EFIVAR);
+
+/*
+ * efivar_set_variable_blocking() - local helper function for set_variable
+ *
+ * Must be called with efivars_lock held.
+ */
+static efi_status_t
+efivar_set_variable_blocking(efi_char16_t *name, efi_guid_t *vendor,
+			     u32 attr, unsigned long data_size, void *data)
+{
+	efi_status_t status;
+
+	if (data_size > 0) {
+		status = check_var_size(attr, data_size +
+					      ucs2_strsize(name, 1024));
+		if (status != EFI_SUCCESS)
+			return status;
+	}
+	return __efivars->ops->set_variable(name, vendor, attr, data_size, data);
+}
+
+/*
+ * efivar_set_variable_locked() - set a variable identified by name/vendor
+ *
+ * Must be called with efivars_lock held. If @nonblocking is set, it will use
+ * non-blocking primitives so it is guaranteed not to sleep.
+ */
+efi_status_t efivar_set_variable_locked(efi_char16_t *name, efi_guid_t *vendor,
+					u32 attr, unsigned long data_size,
+					void *data, bool nonblocking)
+{
+	efi_set_variable_t *setvar;
+	efi_status_t status;
+
+	if (!nonblocking)
+		return efivar_set_variable_blocking(name, vendor, attr,
+						    data_size, data);
+
+	/*
+	 * If no _nonblocking variant exists, the ordinary one
+	 * is assumed to be non-blocking.
+	 */
+	setvar = __efivars->ops->set_variable_nonblocking ?:
+		 __efivars->ops->set_variable;
+
+	if (data_size > 0) {
+		status = check_var_size_nonblocking(attr, data_size +
+							  ucs2_strsize(name, 1024));
+		if (status != EFI_SUCCESS)
+			return status;
+	}
+	return setvar(name, vendor, attr, data_size, data);
+}
+EXPORT_SYMBOL_NS_GPL(efivar_set_variable_locked, EFIVAR);
+
+/*
+ * efivar_set_variable() - set a variable identified by name/vendor
+ *
+ * Can be called without holding the efivars_lock. Will sleep on obtaining the
+ * lock, or on obtaining other locks that are needed in order to complete the
+ * call.
+ */
+efi_status_t efivar_set_variable(efi_char16_t *name, efi_guid_t *vendor,
+				 u32 attr, unsigned long data_size, void *data)
+{
+	efi_status_t status;
+
+	if (efivar_lock())
+		return EFI_ABORTED;
+
+	status = efivar_set_variable_blocking(name, vendor, attr, data_size, data);
+	efivar_unlock();
+	return status;
+}
+EXPORT_SYMBOL_NS_GPL(efivar_set_variable, EFIVAR);