Reads of dgnc_poll_tick are protected by dgnc_poll_lock spinlock, but the write
to dgnc_poll_tick is not. It could theoretically race.
Signed-off-by: Salah Triki <salah.tr...@acm.org>
---
drivers/staging/dgnc/dgnc_driver.c | 2 +-
drivers/staging/dgnc/dgnc_driver.h | 1 +
drivers/staging/dgnc/dgnc_sysfs.c | 9 ++++++++-
3 files changed, 10 insertions(+), 2 deletions(-)
diff --git a/drivers/staging/dgnc/dgnc_driver.c
b/drivers/staging/dgnc/dgnc_driver.c
index 7546aff..b402c9e 100644
--- a/drivers/staging/dgnc/dgnc_driver.c
+++ b/drivers/staging/dgnc/dgnc_driver.c
@@ -64,6 +64,7 @@ static const struct file_operations dgnc_BoardFops = {
uint dgnc_NumBoards;
struct dgnc_board *dgnc_Board[MAXBOARDS];
DEFINE_SPINLOCK(dgnc_global_lock);
+DEFINE_SPINLOCK(dgnc_poll_lock); /* Poll scheduling lock */
uint dgnc_Major;
int dgnc_poll_tick = 20; /* Poll interval - 20 ms */
@@ -75,7 +76,6 @@ static struct class *dgnc_class;
/*
* Poller stuff
*/
-static DEFINE_SPINLOCK(dgnc_poll_lock); /* Poll scheduling lock */
static ulong dgnc_poll_time; /* Time of next poll */
static uint dgnc_poll_stop; /* Used to tell poller to stop */
static struct timer_list dgnc_poll_timer;
diff --git a/drivers/staging/dgnc/dgnc_driver.h
b/drivers/staging/dgnc/dgnc_driver.h
index 06ece51..c61884c 100644
--- a/drivers/staging/dgnc/dgnc_driver.h
+++ b/drivers/staging/dgnc/dgnc_driver.h
@@ -390,6 +390,7 @@ struct channel_t {
extern uint dgnc_Major; /* Our driver/mgmt major */
extern int dgnc_poll_tick; /* Poll interval - 20 ms */
extern spinlock_t dgnc_global_lock; /* Driver global spinlock */
+extern spinlock_t dgnc_poll_lock; /* Poll scheduling lock */
extern uint dgnc_NumBoards; /* Total number of boards */
extern struct dgnc_board *dgnc_Board[MAXBOARDS]; /* Array of board
structs */
diff --git a/drivers/staging/dgnc/dgnc_sysfs.c
b/drivers/staging/dgnc/dgnc_sysfs.c
index 44db870..48b6056 100644
--- a/drivers/staging/dgnc/dgnc_sysfs.c
+++ b/drivers/staging/dgnc/dgnc_sysfs.c
@@ -56,11 +56,18 @@ static ssize_t dgnc_driver_pollrate_show(struct
device_driver *ddp, char *buf)
static ssize_t dgnc_driver_pollrate_store(struct device_driver *ddp,
const char *buf, size_t count)
{
+ unsigned long flags;
+ int tick;
int ret;
- ret = sscanf(buf, "%d\n", &dgnc_poll_tick);
+ ret = sscanf(buf, "%d\n", &tick);
if (ret != 1)
return -EINVAL;
+
+ spin_lock_irqsave(&dgnc_poll_lock, flags);
+ dgnc_poll_tick = tick;
+ spin_unlock_irqrestore(&dgnc_poll_lock, flags);
+
return count;
}
static DRIVER_ATTR(pollrate, (S_IRUSR | S_IWUSR), dgnc_driver_pollrate_show,
--
1.9.1
_______________________________________________
devel mailing list
de...@linuxdriverproject.org
http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
