[PATCH 4/5] firewire: core: use spinlock without irqsave for card split_timeout member

[Takashi Sakamoto]

Asynchronous packet callbacks are now always invoked in process context.
Therefore, the split_timeout member is not accessed from IRQ context.

Use spin_lock() for the split_timeout member since disabling local IRQs
is unnecessary.

Signed-off-by: Takashi Sakamoto <o-takashi@xxxxxxxxxxxxx>
---
 drivers/firewire/core-transaction.c | 18 ++++--------------
 1 file changed, 4 insertions(+), 14 deletions(-)

diff --git a/drivers/firewire/core-transaction.c b/drivers/firewire/core-transaction.c
index 995c2001bee0..91ed85b7aa22 100644
--- a/drivers/firewire/core-transaction.c
+++ b/drivers/firewire/core-transaction.c
@@ -204,9 +204,7 @@ static void transmit_complete_callback(struct fw_packet *packet,
 	{
 		unsigned int delta;
 
-		// NOTE: This can be without irqsave when we can guarantee that __fw_send_request() for
-		// local destination never runs in any type of IRQ context.
-		scoped_guard(spinlock_irqsave, &card->split_timeout.lock) {
+		scoped_guard(spinlock, &card->split_timeout.lock) {
 			t->split_timeout_cycle =
 				compute_split_timeout_timestamp(card, packet->timestamp) & 0xffff;
 			delta = card->split_timeout.jiffies;
@@ -900,9 +898,7 @@ static struct fw_request *allocate_request(struct fw_card *card,
 		return NULL;
 	kref_init(&request->kref);
 
-	// NOTE: This can be without irqsave when we can guarantee that __fw_send_request() for
-	// local destination never runs in any type of IRQ context.
-	scoped_guard(spinlock_irqsave, &card->split_timeout.lock)
+	scoped_guard(spinlock, &card->split_timeout.lock)
 		request->response.timestamp = compute_split_timeout_timestamp(card, p->timestamp);
 
 	request->response.speed = p->speed;
@@ -1340,10 +1336,7 @@ static void handle_registers(struct fw_card *card, struct fw_request *request,
 		if (tcode == TCODE_READ_QUADLET_REQUEST) {
 			*data = cpu_to_be32(card->split_timeout.hi);
 		} else if (tcode == TCODE_WRITE_QUADLET_REQUEST) {
-			// NOTE: This can be without irqsave when we can guarantee that
-			// __fw_send_request() for local destination never runs in any type of IRQ
-			// context.
-			scoped_guard(spinlock_irqsave, &card->split_timeout.lock) {
+			scoped_guard(spinlock, &card->split_timeout.lock) {
 				card->split_timeout.hi = be32_to_cpu(*data) & 7;
 				update_split_timeout(card);
 			}
@@ -1356,10 +1349,7 @@ static void handle_registers(struct fw_card *card, struct fw_request *request,
 		if (tcode == TCODE_READ_QUADLET_REQUEST) {
 			*data = cpu_to_be32(card->split_timeout.lo);
 		} else if (tcode == TCODE_WRITE_QUADLET_REQUEST) {
-			// NOTE: This can be without irqsave when we can guarantee that
-			// __fw_send_request() for local destination never runs in any type of IRQ
-			// context.
-			scoped_guard(spinlock_irqsave, &card->split_timeout.lock) {
+			scoped_guard(spinlock, &card->split_timeout.lock) {
 				card->split_timeout.lo = be32_to_cpu(*data) & 0xfff80000;
 				update_split_timeout(card);
 			}
-- 
2.53.0