linux-kernel - [PATCH 3/3] uio: uio_dmem_genirq: Use non-atomic bit operations in irq config and handling

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Date:   Fri, 30 Sep 2022 19:40:59 -0300
From:   Rafael Mendonca <rafaelmendsr@...il.com>
To:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Jia-Ju Bai <baijiaju1990@...il.com>,
        "Hans J. Koch" <hjk@...sjkoch.de>,
        Damian Hobson-Garcia <dhobsong@...l.co.jp>
Cc:     Rafael Mendonca <rafaelmendsr@...il.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH 3/3] uio: uio_dmem_genirq: Use non-atomic bit operations in irq config and handling

This finishes the port of the irq configuration and handling from
"uio_pdrv_genirq" to "uio_dmem_genirq". It changes the atomic
bit-manipulation routines to their non-atomic counterparts as we are
already guarding the code by spinlock.

Split out from commit 34cb27528398 ("UIO: Fix concurrency issue").

Signed-off-by: Rafael Mendonca <rafaelmendsr@...il.com>
---
 drivers/uio/uio_dmem_genirq.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/uio/uio_dmem_genirq.c b/drivers/uio/uio_dmem_genirq.c
index 792c3e9c9ce5..5313307c2754 100644
--- a/drivers/uio/uio_dmem_genirq.c
+++ b/drivers/uio/uio_dmem_genirq.c
@@ -41,6 +41,11 @@ struct uio_dmem_genirq_platdata {
 	unsigned int refcnt;
 };
 
+/* Bits in uio_dmem_genirq_platdata.flags */
+enum {
+	UIO_IRQ_DISABLED = 0,
+};
+
 static int uio_dmem_genirq_open(struct uio_info *info, struct inode *inode)
 {
 	struct uio_dmem_genirq_platdata *priv = info->priv;
@@ -111,7 +116,7 @@ static irqreturn_t uio_dmem_genirq_handler(int irq, struct uio_info *dev_info)
 	 */
 
 	spin_lock(&priv->lock);
-	if (!test_and_set_bit(0, &priv->flags))
+	if (!__test_and_set_bit(UIO_IRQ_DISABLED, &priv->flags))
 		disable_irq_nosync(irq);
 	spin_unlock(&priv->lock);
 
@@ -133,10 +138,10 @@ static int uio_dmem_genirq_irqcontrol(struct uio_info *dev_info, s32 irq_on)
 
 	spin_lock_irqsave(&priv->lock, flags);
 	if (irq_on) {
-		if (test_and_clear_bit(0, &priv->flags))
+		if (__test_and_clear_bit(UIO_IRQ_DISABLED, &priv->flags))
 			enable_irq(dev_info->irq);
 	} else {
-		if (!test_and_set_bit(0, &priv->flags))
+		if (!__test_and_set_bit(UIO_IRQ_DISABLED, &priv->flags))
 			disable_irq_nosync(dev_info->irq);
 	}
 	spin_unlock_irqrestore(&priv->lock, flags);
-- 
2.34.1