[PATCH linux dev-4.10 v2 3/3] drivers: fsi: occ: switch to irqsave and irqrestore

Eddie James eajames at linux.vnet.ibm.com
Thu Feb 15 08:31:48 AEDT 2018


Fix spinlocking by storing the interrupt state and restoring that state
when unlocking, instead of blindly disabling and re-enabling all irqs.

Signed-off-by: Eddie James <eajames at linux.vnet.ibm.com>
---
 drivers/fsi/occ.c | 44 +++++++++++++++++++++++++-------------------
 1 file changed, 25 insertions(+), 19 deletions(-)

diff --git a/drivers/fsi/occ.c b/drivers/fsi/occ.c
index adc64f3..edb5e977 100644
--- a/drivers/fsi/occ.c
+++ b/drivers/fsi/occ.c
@@ -118,18 +118,19 @@ struct occ_client {
 static int occ_enqueue_xfr(struct occ_xfr *xfr)
 {
 	int empty;
+	unsigned long flags;
 	struct occ_client *client = to_client(xfr);
 	struct occ *occ = client->occ;
 
 	if (occ->cancel)
 		return -ENODEV;
 
-	spin_lock_irq(&occ->list_lock);
+	spin_lock_irqsave(&occ->list_lock, flags);
 
 	empty = list_empty(&occ->xfrs);
 	list_add_tail(&xfr->link, &occ->xfrs);
 
-	spin_unlock_irq(&occ->list_lock);
+	spin_unlock_irqrestore(&occ->list_lock, flags);
 
 	if (empty)
 		queue_work(occ_wq, &occ->work);
@@ -201,6 +202,7 @@ static ssize_t occ_read_common(struct occ_client *client, char __user *ubuf,
 	size_t bytes;
 	struct occ_xfr *xfr;
 	struct occ *occ;
+	unsigned long flags;
 
 	if (!client)
 		return -ENODEV;
@@ -212,7 +214,7 @@ static ssize_t occ_read_common(struct occ_client *client, char __user *ubuf,
 	xfr = &client->xfr;
 	occ = client->occ;
 
-	spin_lock_irq(&client->lock);
+	spin_lock_irqsave(&client->lock, flags);
 
 	if (!test_bit(CLIENT_XFR_PENDING, &client->flags)) {
 		/* we just finished reading all data, return 0 */
@@ -232,12 +234,12 @@ static ssize_t occ_read_common(struct occ_client *client, char __user *ubuf,
 			goto done;
 		}
 
-		spin_unlock_irq(&client->lock);
+		spin_unlock_irqrestore(&client->lock, flags);
 
 		rc = wait_event_interruptible(client->wait,
 					      occ_read_ready(xfr, occ));
 
-		spin_lock_irq(&client->lock);
+		spin_lock_irqsave(&client->lock, flags);
 
 		if (!test_bit(XFR_COMPLETE, &xfr->flags)) {
 			if (occ->cancel || test_bit(XFR_CANCELED, &xfr->flags))
@@ -274,7 +276,7 @@ static ssize_t occ_read_common(struct occ_client *client, char __user *ubuf,
 	rc = bytes;
 
 done:
-	spin_unlock_irq(&client->lock);
+	spin_unlock_irqrestore(&client->lock, flags);
 	occ_put_client(client);
 	return rc;
 }
@@ -293,6 +295,7 @@ static ssize_t occ_write_common(struct occ_client *client,
 {
 	int rc;
 	unsigned int i;
+	unsigned long flags;
 	u16 data_length, checksum = 0;
 	struct occ_xfr *xfr;
 
@@ -305,7 +308,7 @@ static ssize_t occ_write_common(struct occ_client *client,
 	occ_get_client(client);
 	xfr = &client->xfr;
 
-	spin_lock_irq(&client->lock);
+	spin_lock_irqsave(&client->lock, flags);
 
 	if (test_bit(CLIENT_XFR_PENDING, &client->flags)) {
 		rc = -EBUSY;
@@ -353,7 +356,7 @@ static ssize_t occ_write_common(struct occ_client *client,
 	rc = len;
 
 done:
-	spin_unlock_irq(&client->lock);
+	spin_unlock_irqrestore(&client->lock, flags);
 	occ_put_client(client);
 	return rc;
 }
@@ -370,6 +373,7 @@ static int occ_release_common(struct occ_client *client)
 {
 	struct occ *occ;
 	struct occ_xfr *xfr;
+	unsigned long flags;
 
 	if (!client)
 		return -ENODEV;
@@ -377,13 +381,13 @@ static int occ_release_common(struct occ_client *client)
 	xfr = &client->xfr;
 	occ = client->occ;
 
-	spin_lock_irq(&client->lock);
+	spin_lock_irqsave(&client->lock, flags);
 
 	set_bit(XFR_CANCELED, &xfr->flags);
 	if (!test_bit(CLIENT_XFR_PENDING, &client->flags))
 		goto done;
 
-	spin_lock_irq(&occ->list_lock);
+	spin_lock(&occ->list_lock);
 
 	if (!test_bit(XFR_IN_PROGRESS, &xfr->flags)) {
 		/* already deleted from list if complete */
@@ -391,12 +395,12 @@ static int occ_release_common(struct occ_client *client)
 			list_del(&xfr->link);
 	}
 
-	spin_unlock_irq(&occ->list_lock);
+	spin_unlock(&occ->list_lock);
 
 	wake_up_all(&client->wait);
 
 done:
-	spin_unlock_irq(&client->lock);
+	spin_unlock_irqrestore(&client->lock, flags);
 
 	occ_put_client(client);
 	return 0;
@@ -606,6 +610,7 @@ static void occ_worker(struct work_struct *work)
 {
 	int rc = 0, empty;
 	u16 resp_data_length;
+	unsigned long flags;
 	unsigned long start;
 	const unsigned long timeout = msecs_to_jiffies(OCC_TIMEOUT_MS);
 	const long int wait_time = msecs_to_jiffies(OCC_CMD_IN_PRG_WAIT_MS);
@@ -619,11 +624,11 @@ static void occ_worker(struct work_struct *work)
 	if (occ->cancel)
 		return;
 
-	spin_lock_irq(&occ->list_lock);
+	spin_lock_irqsave(&occ->list_lock, flags);
 
 	xfr = list_first_entry_or_null(&occ->xfrs, struct occ_xfr, link);
 	if (!xfr) {
-		spin_unlock_irq(&occ->list_lock);
+		spin_unlock_irqrestore(&occ->list_lock, flags);
 		return;
 	}
 
@@ -632,7 +637,7 @@ static void occ_worker(struct work_struct *work)
 	resp = (struct occ_response *)xfr->buf;
 	set_bit(XFR_IN_PROGRESS, &xfr->flags);
 
-	spin_unlock_irq(&occ->list_lock);
+	spin_unlock_irqrestore(&occ->list_lock, flags);
 	mutex_lock(&occ->occ_lock);
 
 	start = jiffies;
@@ -686,13 +691,13 @@ static void occ_worker(struct work_struct *work)
 	xfr->rc = rc;
 	set_bit(XFR_COMPLETE, &xfr->flags);
 
-	spin_lock_irq(&occ->list_lock);
+	spin_lock_irqsave(&occ->list_lock, flags);
 
 	clear_bit(XFR_IN_PROGRESS, &xfr->flags);
 	list_del(&xfr->link);
 	empty = list_empty(&occ->xfrs);
 
-	spin_unlock_irq(&occ->list_lock);
+	spin_unlock_irqrestore(&occ->list_lock, flags);
 
 	wake_up_interruptible(&client->wait);
 	occ_put_client(client);
@@ -810,15 +815,16 @@ static int occ_remove(struct platform_device *pdev)
 	struct occ *occ = platform_get_drvdata(pdev);
 	struct occ_xfr *xfr;
 	struct occ_client *client;
+	unsigned long flags;
 
 	occ->cancel = true;
 
-	spin_lock_irq(&occ->list_lock);
+	spin_lock_irqsave(&occ->list_lock, flags);
 	list_for_each_entry(xfr, &occ->xfrs, link) {
 		client = to_client(xfr);
 		wake_up_all(&client->wait);
 	}
-	spin_unlock_irq(&occ->list_lock);
+	spin_unlock_irqrestore(&occ->list_lock, flags);
 
 	misc_deregister(&occ->mdev);
 	device_for_each_child(&pdev->dev, NULL, occ_unregister_child);
-- 
1.8.3.1



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