[MIPS] RTLX: Protect rtlx_{read,write} with mutex.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/kernel/rtlx.c b/arch/mips/kernel/rtlx.c
index 0441c7c..745649e 100644 (file)
--- a/arch/mips/kernel/rtlx.c
+++ b/arch/mips/kernel/rtlx.c
@@ -54,6 +54,7 @@ static struct chan_waitqueues {
        wait_queue_head_t rt_queue;
        wait_queue_head_t lx_queue;
        atomic_t in_open;
+       struct mutex mutex;
 } channel_wqs[RTLX_CHANNELS];
 
 static struct irqaction irq;
@@ -314,6 +315,7 @@ ssize_t rtlx_read(int index, void *buff, size_t count, int user)
 
        lx = &rtlx->channel[index];
 
+       mutex_lock(&channel_wqs[index].mutex);
        smp_rmb();
        lx_write = lx->lx_write;
 
@@ -334,6 +336,7 @@ ssize_t rtlx_read(int index, void *buff, size_t count, int user)
        smp_wmb();
        lx->lx_read = (lx->lx_read + count) % lx->buffer_size;
        smp_wmb();
+       mutex_unlock(&channel_wqs[index].mutex);
 
        return count;
 }
@@ -349,6 +352,7 @@ ssize_t rtlx_write(int index, void *buffer, size_t count, int user)
 
        rt = &rtlx->channel[index];
 
+       mutex_lock(&channel_wqs[index].mutex);
        smp_rmb();
        rt_read = rt->rt_read;
 
@@ -368,6 +372,7 @@ ssize_t rtlx_write(int index, void *buffer, size_t count, int user)
        smp_wmb();
        rt->rt_write = (rt->rt_write + count) % rt->buffer_size;
        smp_wmb();
+       mutex_unlock(&channel_wqs[index].mutex);
 
        return count;
 }
@@ -486,6 +491,7 @@ static int rtlx_module_init(void)
                init_waitqueue_head(&channel_wqs[i].rt_queue);
                init_waitqueue_head(&channel_wqs[i].lx_queue);
                atomic_set(&channel_wqs[i].in_open, 0);
+               mutex_init(&channel_wqs[i].mutex);
 
                dev = device_create(mt_class, NULL, MKDEV(major, i),
                                    "%s%d", module_name, i);