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Diffstat (limited to 'arch/mips/kernel/rtlx.c')
-rw-r--r--arch/mips/kernel/rtlx.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/mips/kernel/rtlx.c b/arch/mips/kernel/rtlx.c
index 0441c7c1e44..745649e15ad 100644
--- 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);