[PATCH 2/4] ipmi: bt-bmc: Track open state per device

[Yu-Che Hsieh via B4 Relay]

From: Yu-Che Hsieh <yc_hsieh at aspeedtech.com>

The driver uses a global open count to allow only one userspace client

to open the BT device at a time. This works for a single device, but

also prevents independent BT device instances from being opened

concurrently.

Move the open count into struct bt_bmc so each device instance tracks

its own open state. This preserves the single-open behavior per device

while allowing multiple BT devices to operate independently.

Signed-off-by: Yu-Che Hsieh <yc_hsieh at aspeedtech.com>
---
 drivers/char/ipmi/bt-bmc.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/char/ipmi/bt-bmc.c b/drivers/char/ipmi/bt-bmc.c
index f3c67272502f..486ecc0b6815 100644
--- a/drivers/char/ipmi/bt-bmc.c
+++ b/drivers/char/ipmi/bt-bmc.c
@@ -64,10 +64,9 @@ struct bt_bmc {
 	wait_queue_head_t	queue;
 	struct timer_list	poll_timer;
 	struct mutex		mutex;
+	atomic_t		open_count;
 };
 
-static atomic_t open_count = ATOMIC_INIT(0);
-
 static u8 bt_inb(struct bt_bmc *bt_bmc, int reg)
 {
 	return readb(bt_bmc->base + reg);
@@ -152,12 +151,12 @@ static int bt_bmc_open(struct inode *inode, struct file *file)
 {
 	struct bt_bmc *bt_bmc = file_bt_bmc(file);
 
-	if (atomic_inc_return(&open_count) == 1) {
+	if (atomic_inc_return(&bt_bmc->open_count) == 1) {
 		clr_b_busy(bt_bmc);
 		return 0;
 	}
 
-	atomic_dec(&open_count);
+	atomic_dec(&bt_bmc->open_count);
 	return -EBUSY;
 }
 
@@ -313,7 +312,7 @@ static int bt_bmc_release(struct inode *inode, struct file *file)
 {
 	struct bt_bmc *bt_bmc = file_bt_bmc(file);
 
-	atomic_dec(&open_count);
+	atomic_dec(&bt_bmc->open_count);
 	set_b_busy(bt_bmc);
 	return 0;
 }
@@ -425,6 +424,8 @@ static int bt_bmc_probe(struct platform_device *pdev)
 	if (IS_ERR(bt_bmc->base))
 		return PTR_ERR(bt_bmc->base);
 
+	atomic_set(&bt_bmc->open_count, 0);
+
 	mutex_init(&bt_bmc->mutex);
 	init_waitqueue_head(&bt_bmc->queue);
 

-- 
2.34.1