commit bc4809e939b91c9642f1ddaea732e2d432ee6af6
author Ralf Baechle <ralf@linux-mips.org> Thu Mar 15 17:13:47 2007 +0000
committer Ralf Baechle <ralf@linux-mips.org> Sat Mar 17 01:03:28 2007 +0000
tree 0536fee2c956f0caa2379041a46bdc8db66a6d74
parent 61dcc6f4d9ed5db71f4f0be9026bdd09f1a7dc06

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

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

arch/mips/kernel/rtlx.c

diff --git a/arch/mips/kernel/rtlx.c b/arch/mips/kernel/rtlx.c
index 0441c7c..745649e 100644
--- a/arch/mips/kernel/rtlx.c
+++ b/arch/mips/kernel/rtlx.c
@@ -54,6 +54,7 @@
 	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 @@
 
 	lx = &rtlx->channel[index];
 
+	mutex_lock(&channel_wqs[index].mutex);
 	smp_rmb();
 	lx_write = lx->lx_write;
 
@@ -334,6 +336,7 @@
 	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 @@
 
 	rt = &rtlx->channel[index];
 
+	mutex_lock(&channel_wqs[index].mutex);
 	smp_rmb();
 	rt_read = rt->rt_read;
 
@@ -368,6 +372,7 @@
 	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 @@
 		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);