[PATCH V8 14/23] coresight: etb10: moving to local atomic operations
From: mathieu.poirier@linaro.org (Mathieu Poirier)
Date: 2016-01-14 21:50:59
Also in:
lkml
Subsystem:
arm/coresight framework and drivers, hardware tracing facilities, the rest · Maintainers:
Suzuki K Poulose, Alexander Shishkin, Linus Torvalds
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> --- drivers/hwtracing/coresight/coresight-etb10.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etb10.c b/drivers/hwtracing/coresight/coresight-etb10.c
index 1301edc44629..09e306361e4f 100644
--- a/drivers/hwtracing/coresight/coresight-etb10.c
+++ b/drivers/hwtracing/coresight/coresight-etb10.c@@ -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;
--
2.1.4