From: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx>
The mrst_max3110.c driver uses an open coded, non atomic variable
to create exclusion between two of its worker threads. More than that,
while the main thread does a proper set-work-clear sequence,
the other thread only does a test, with the result that no actual
exclusion is happening.
this patch replaces this open coded variable with a proper mutex
in addition, the 'lock' spinlock is removed from the per adapter structure,
the lock was only ever initialized but never used
Signed-off-by: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx>
Signed-off-by: Alan Cox <alan@xxxxxxxxxxxxxxx>
---
drivers/serial/mrst_max3110.c | 15 ++++++++-------
1 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/drivers/serial/mrst_max3110.c b/drivers/serial/mrst_max3110.c
index f9c01ae..0341853 100644
--- a/drivers/serial/mrst_max3110.c
+++ b/drivers/serial/mrst_max3110.c
@@ -56,8 +56,7 @@ struct uart_max3110 {
wait_queue_head_t wq;
struct task_struct *main_thread;
struct task_struct *read_thread;
- int mthread_up;
- spinlock_t lock;
+ struct mutex thread_mutex;;
u32 baud;
u16 cur_conf;
@@ -397,7 +396,8 @@ static int max3110_main_thread(void *_max)
atomic_read(&max->con_tx_need) ||
atomic_read(&max->uart_tx_need)) ||
kthread_should_stop());
- max->mthread_up = 1;
+
+ mutex_lock(&max->thread_mutex);
#ifdef CONFIG_MRST_MAX3110_IRQ
if (atomic_read(&max->irq_pending)) {
@@ -417,7 +417,7 @@ static int max3110_main_thread(void *_max)
transmit_char(max);
atomic_set(&max->uart_tx_need, 0);
}
- max->mthread_up = 0;
+ mutex_unlock(&max->thread_mutex);
} while (!kthread_should_stop());
return ret;
@@ -444,8 +444,9 @@ static int max3110_read_thread(void *_max)
pr_info(PR_FMT "start read thread\n");
do {
- if (!max->mthread_up)
- max3110_console_receive(max);
+ mutex_lock(&max->thread_mutex);
+ max3110_console_receive(max);
+ mutex_unlock(&max->thread_mutex);
set_current_state(TASK_INTERRUPTIBLE);
schedule_timeout(HZ / 20);
@@ -745,7 +746,7 @@ static int serial_m3110_probe(struct spi_device *spi)
max->name = spi->modalias; /* use spi name as the name */
max->irq = (u16)spi->irq;
- spin_lock_init(&max->lock);
+ mutex_init(&max->thread_mutex);
max->word_7bits = 0;
max->parity = 0;
--
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