[MIPS] RTLX: Protect rtlx_{read,write} with mutex. (bc4809e9) · Commits · e / devices / android_kernel_xiaomi_markw

arch/mips/kernel/rtlx.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -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);