linux-kernel - [PATCH linux-next v2] serial: dz: use atomic_inc and atomic_dec instead of atomic

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Message-Id: <20221013081220.351415-1-xu.panda668@gmail.com>
Date:   Thu, 13 Oct 2022 08:12:22 +0000
From:   xu.panda668@...il.com
To:     macro@...am.me.uk
Cc:     jirislaby@...nel.org, linux-kernel@...r.kernel.org,
        Xu Panda <xu.panda@....com.cn>, Zeal Robot <zealci@....com.cn>
Subject: [PATCH linux-next v2] serial: dz: use atomic_inc and atomic_dec instead of atomic_add

From: Xu Panda <xu.panda@....com.cn>

It's better to use atomic_dec_return() etc. instead of 
atomic_add_return().

Reported-by: Zeal Robot <zealci@....com.cn>
Signed-off-by: Xu Panda <xu.panda@....com.cn>
---
 drivers/tty/serial/dz.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/tty/serial/dz.c b/drivers/tty/serial/dz.c
index 829b452daee9..84476cef3278 100644
--- a/drivers/tty/serial/dz.c
+++ b/drivers/tty/serial/dz.c
@@ -404,14 +404,14 @@ static int dz_startup(struct uart_port *uport)
 	int ret;
 	u16 tmp;
 
-	irq_guard = atomic_add_return(1, &mux->irq_guard);
+	irq_guard = atomic_inc_return(&mux->irq_guard);
 	if (irq_guard != 1)
 		return 0;
 
 	ret = request_irq(dport->port.irq, dz_interrupt,
 			  IRQF_SHARED, "dz", mux);
 	if (ret) {
-		atomic_add(-1, &mux->irq_guard);
+		atomic_dec(&mux->irq_guard);
 		printk(KERN_ERR "dz: Cannot get IRQ %d!\n", dport->port.irq);
 		return ret;
 	}
@@ -448,7 +448,7 @@ static void dz_shutdown(struct uart_port *uport)
 	dz_stop_tx(&dport->port);
 	spin_unlock_irqrestore(&dport->port.lock, flags);
 
-	irq_guard = atomic_add_return(-1, &mux->irq_guard);
+	irq_guard = atomic_dec_return(&mux->irq_guard);
 	if (!irq_guard) {
 		/* Disable interrupts.  */
 		tmp = dz_in(dport, DZ_CSR);
@@ -668,7 +668,7 @@ static void dz_release_port(struct uart_port *uport)
 	iounmap(uport->membase);
 	uport->membase = NULL;
 
-	map_guard = atomic_add_return(-1, &mux->map_guard);
+	map_guard = atomic_dec_return(&mux->map_guard);
 	if (!map_guard)
 		release_mem_region(uport->mapbase, dec_kn_slot_size);
 }
@@ -691,11 +691,11 @@ static int dz_request_port(struct uart_port *uport)
 	int map_guard;
 	int ret;
 
-	map_guard = atomic_add_return(1, &mux->map_guard);
+	map_guard = atomic_inc_return(&mux->map_guard);
 	if (map_guard == 1) {
 		if (!request_mem_region(uport->mapbase, dec_kn_slot_size,
 					"dz")) {
-			atomic_add(-1, &mux->map_guard);
+			atomic_dec(&mux->map_guard);
 			printk(KERN_ERR
 			       "dz: Unable to reserve MMIO resource\n");
 			return -EBUSY;
@@ -703,7 +703,7 @@ static int dz_request_port(struct uart_port *uport)
 	}
 	ret = dz_map_port(uport);
 	if (ret) {
-		map_guard = atomic_add_return(-1, &mux->map_guard);
+		map_guard = atomic_dec_return(&mux->map_guard);
 		if (!map_guard)
 			release_mem_region(uport->mapbase, dec_kn_slot_size);
 		return ret;
-- 
2.15.2