linux-kernel - [PATCH 05/17] firewire: core: use guard macro to maintain RCU scope for transaction address handler

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Message-ID: <20240804130225.243496-6-o-takashi@sakamocchi.jp>
Date: Sun,  4 Aug 2024 22:02:12 +0900
From: Takashi Sakamoto <o-takashi@...amocchi.jp>
To: linux1394-devel@...ts.sourceforge.net
Cc: linux-kernel@...r.kernel.org
Subject: [PATCH 05/17] firewire: core: use guard macro to maintain RCU scope for transaction address handler

The core function maintains address handlers by list. RCU is utilized
for efficient read access to any entries in the list.

This commit uses guard macro to maintain RCU locking and releasing.

Signed-off-by: Takashi Sakamoto <o-takashi@...amocchi.jp>
---
 drivers/firewire/core-transaction.c | 35 +++++++++++++----------------
 1 file changed, 15 insertions(+), 20 deletions(-)

diff --git a/drivers/firewire/core-transaction.c b/drivers/firewire/core-transaction.c
index 2a2cbd6e2f9b..a0224d4d8e11 100644
--- a/drivers/firewire/core-transaction.c
+++ b/drivers/firewire/core-transaction.c
@@ -925,16 +925,14 @@ static void handle_exclusive_region_request(struct fw_card *card,
 	if (tcode == TCODE_LOCK_REQUEST)
 		tcode = 0x10 + async_header_get_extended_tcode(p->header);
 
-	rcu_read_lock();
-	handler = lookup_enclosing_address_handler(&address_handler_list,
-						   offset, request->length);
-	if (handler)
-		handler->address_callback(card, request,
-					  tcode, destination, source,
-					  p->generation, offset,
-					  request->data, request->length,
-					  handler->callback_data);
-	rcu_read_unlock();
+	scoped_guard(rcu) {
+		handler = lookup_enclosing_address_handler(&address_handler_list, offset,
+							   request->length);
+		if (handler)
+			handler->address_callback(card, request, tcode, destination, source,
+						  p->generation, offset, request->data,
+						  request->length, handler->callback_data);
+	}
 
 	if (!handler)
 		fw_send_response(card, request, RCODE_ADDRESS_ERROR);
@@ -967,17 +965,14 @@ static void handle_fcp_region_request(struct fw_card *card,
 		return;
 	}
 
-	rcu_read_lock();
-	list_for_each_entry_rcu(handler, &address_handler_list, link) {
-		if (is_enclosing_handler(handler, offset, request->length))
-			handler->address_callback(card, request, tcode,
-						  destination, source,
-						  p->generation, offset,
-						  request->data,
-						  request->length,
-						  handler->callback_data);
+	scoped_guard(rcu) {
+		list_for_each_entry_rcu(handler, &address_handler_list, link) {
+			if (is_enclosing_handler(handler, offset, request->length))
+				handler->address_callback(card, request, tcode, destination, source,
+							  p->generation, offset, request->data,
+							  request->length, handler->callback_data);
+		}
 	}
-	rcu_read_unlock();
 
 	fw_send_response(card, request, RCODE_COMPLETE);
 }
-- 
2.43.0