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| author | Arjan van de Ven <arjan@linux.intel.com> | 2010-06-17 11:02:06 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-08-10 13:47:39 -0700 |
| commit | 68c16b4117cc746a91897d629b61e5f2af18c225 (patch) | |
| tree | f681c2966cf731a32edc0f33e072a6f4b3272e5e /drivers/serial | |
| parent | 99dd3f6b7e2ef5179f67503a401a99141708687a (diff) | |
| download | lwn-68c16b4117cc746a91897d629b61e5f2af18c225.tar.gz lwn-68c16b4117cc746a91897d629b61e5f2af18c225.zip | |
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: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/serial')
| -rw-r--r-- | 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 f9c01aeb6f80..0341853e0c28 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; |