[PATCH v2 02/17] firewire: core: use guard macro to maintain the list of card

[Takashi Sakamoto]

The core function maintains registered cards by list. The concurrent
access to the list is protected by static mutex.

This commit uses guard macro to maintain the mutex.

Signed-off-by: Takashi Sakamoto <o-takashi@xxxxxxxxxxxxx>
---
 drivers/firewire/core-card.c | 44 +++++++++++++++---------------------
 1 file changed, 18 insertions(+), 26 deletions(-)

diff --git a/drivers/firewire/core-card.c b/drivers/firewire/core-card.c
index f8b99dd6cd82..79a5b19e9d18 100644
--- a/drivers/firewire/core-card.c
+++ b/drivers/firewire/core-card.c
@@ -168,7 +168,6 @@ static size_t required_space(struct fw_descriptor *desc)
 int fw_core_add_descriptor(struct fw_descriptor *desc)
 {
 	size_t i;
-	int ret;
 
 	/*
 	 * Check descriptor is valid; the length of all blocks in the
@@ -182,29 +181,25 @@ int fw_core_add_descriptor(struct fw_descriptor *desc)
 	if (i != desc->length)
 		return -EINVAL;
 
-	mutex_lock(&card_mutex);
+	guard(mutex)(&card_mutex);
 
-	if (config_rom_length + required_space(desc) > 256) {
-		ret = -EBUSY;
-	} else {
-		list_add_tail(&desc->link, &descriptor_list);
-		config_rom_length += required_space(desc);
-		descriptor_count++;
-		if (desc->immediate > 0)
-			descriptor_count++;
-		update_config_roms();
-		ret = 0;
-	}
+	if (config_rom_length + required_space(desc) > 256)
+		return -EBUSY;
 
-	mutex_unlock(&card_mutex);
+	list_add_tail(&desc->link, &descriptor_list);
+	config_rom_length += required_space(desc);
+	descriptor_count++;
+	if (desc->immediate > 0)
+		descriptor_count++;
+	update_config_roms();
 
-	return ret;
+	return 0;
 }
 EXPORT_SYMBOL(fw_core_add_descriptor);
 
 void fw_core_remove_descriptor(struct fw_descriptor *desc)
 {
-	mutex_lock(&card_mutex);
+	guard(mutex)(&card_mutex);
 
 	list_del(&desc->link);
 	config_rom_length -= required_space(desc);
@@ -212,8 +207,6 @@ void fw_core_remove_descriptor(struct fw_descriptor *desc)
 	if (desc->immediate > 0)
 		descriptor_count--;
 	update_config_roms();
-
-	mutex_unlock(&card_mutex);
 }
 EXPORT_SYMBOL(fw_core_remove_descriptor);
 
@@ -587,16 +580,16 @@ int fw_card_add(struct fw_card *card,
 	card->link_speed = link_speed;
 	card->guid = guid;
 
-	mutex_lock(&card_mutex);
+	guard(mutex)(&card_mutex);
 
 	generate_config_rom(card, tmp_config_rom);
 	ret = card->driver->enable(card, tmp_config_rom, config_rom_length);
-	if (ret == 0)
-		list_add_tail(&card->link, &card_list);
+	if (ret < 0)
+		return ret;
 
-	mutex_unlock(&card_mutex);
+	list_add_tail(&card->link, &card_list);
 
-	return ret;
+	return 0;
 }
 EXPORT_SYMBOL(fw_card_add);
 
@@ -720,9 +713,8 @@ void fw_core_remove_card(struct fw_card *card)
 				     PHY_LINK_ACTIVE | PHY_CONTENDER, 0);
 	fw_schedule_bus_reset(card, false, true);
 
-	mutex_lock(&card_mutex);
-	list_del_init(&card->link);
-	mutex_unlock(&card_mutex);
+	scoped_guard(mutex, &card_mutex)
+		list_del_init(&card->link);
 
 	/* Switch off most of the card driver interface. */
 	dummy_driver.free_iso_context	= card->driver->free_iso_context;
-- 
2.43.0