Commit 68c16b41 authored by Arjan van de Ven's avatar Arjan van de Ven Committed by Greg Kroah-Hartman
Browse files

serial: replace open coded mutex with a real mutex in mrst_max3110.c 



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: default avatarArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: default avatarAlan Cox <alan@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 99dd3f6b

drivers/serial/mrst_max3110.c

+8 −7
Original line number Diff line number Diff line
@@ -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)

		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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