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coresight: etb10: moving to local atomic operations

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Moving to use local atomic operations to take advantage of the
lockless implementation, something that will come handy when
the ETB is accessed from the Perf subsystem. Also changing the
name of the variable to something more meaningful.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Mathieu Poirier 2016-02-17 17:51:58 -07:00 committed by Greg Kroah-Hartman
parent 882d5e1124
commit 27b10da8ff
1 changed files with 5 additions and 4 deletions
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9
drivers/hwtracing/coresight/coresight-etb10.c
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@ -10,6 +10,7 @@
* GNU General Public License for more details.
*/
#include <asm/local.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
@ -71,7 +72,7 @@
* @csdev: component vitals needed by the framework.
* @miscdev: specifics to handle "/dev/xyz.etb" entry.
* @spinlock: only one at a time pls.
* @in_use: synchronise user space access to etb buffer.
* @reading: synchronise user space access to etb buffer.
* @buf: area of memory where ETB buffer content gets sent.
* @buffer_depth: size of @buf.
* @enable: this ETB is being used.
@ -84,7 +85,7 @@ struct etb_drvdata {
struct coresight_device *csdev;
struct miscdevice miscdev;
spinlock_t spinlock;
atomic_t in_use;
local_t reading;
u8 *buf;
u32 buffer_depth;
bool enable;
@ -277,7 +278,7 @@ static int etb_open(struct inode *inode, struct file *file)
struct etb_drvdata *drvdata = container_of(file->private_data,
struct etb_drvdata, miscdev);
if (atomic_cmpxchg(&drvdata->in_use, 0, 1))
if (local_cmpxchg(&drvdata->reading, 0, 1))
return -EBUSY;
dev_dbg(drvdata->dev, "%s: successfully opened\n", __func__);
@ -313,7 +314,7 @@ static int etb_release(struct inode *inode, struct file *file)
{
struct etb_drvdata *drvdata = container_of(file->private_data,
struct etb_drvdata, miscdev);
atomic_set(&drvdata->in_use, 0);
local_set(&drvdata->reading, 0);
dev_dbg(drvdata->dev, "%s: released\n", __func__);
return 0;