[MIPS] RTLX, VPE: Make open actually atomic. (c4c4018b) · Commits · e / devices / android_kernel_fairphone_FP3

arch/mips/kernel/rtlx.c

+20 −24

Original line number	Diff line number	Diff line
		@@ -53,7 +53,7 @@ static char module_name[] = "rtlx";
		static struct chan_waitqueues {
		wait_queue_head_t rt_queue;
		wait_queue_head_t lx_queue;
		int in_open;
		atomic_t in_open;
		} channel_wqs[RTLX_CHANNELS];

		static struct irqaction irq;
		@@ -148,6 +148,7 @@ int rtlx_open(int index, int can_sleep)
		{
		volatile struct rtlx_info **p;
		struct rtlx_channel *chan;
		enum rtlx_state state;
		int ret = 0;

		if (index >= RTLX_CHANNELS) {
		@@ -155,13 +156,13 @@ int rtlx_open(int index, int can_sleep)
		return -ENOSYS;
		}

		if (channel_wqs[index].in_open) {
		printk(KERN_DEBUG "rtlx_open channel %d already opened\n", index);
		return -EBUSY;
		if (atomic_inc_return(&channel_wqs[index].in_open) > 1) {
		printk(KERN_DEBUG "rtlx_open channel %d already opened\n",
		index);
		ret = -EBUSY;
		goto out_fail;
		}

		channel_wqs[index].in_open++;

		if (rtlx == NULL) {
		if( (p = vpe_get_shared(RTLX_TARG_VPE)) == NULL) {
		if (can_sleep) {
		@@ -175,7 +176,6 @@ int rtlx_open(int index, int can_sleep)
		} else {
		printk(KERN_DEBUG "No SP program loaded, and device "
		"opened with O_NONBLOCK\n");
		channel_wqs[index].in_open = 0;
		ret = -ENOSYS;
		goto out_fail;
		}
		@@ -193,7 +193,6 @@ int rtlx_open(int index, int can_sleep)
		} else {
		printk(" *vpe_get_shared is NULL. "
		"Has an SP program been loaded?\n");
		channel_wqs[index].in_open = 0;
		ret = -ENOSYS;
		goto out_fail;
		}
		@@ -202,31 +201,28 @@ int rtlx_open(int index, int can_sleep)
		if ((unsigned int)*p < KSEG0) {
		printk(KERN_WARNING "vpe_get_shared returned an invalid pointer "
		"maybe an error code %d\n", (int)*p);
		channel_wqs[index].in_open = 0;
		ret = -ENOSYS;
		goto out_fail;
		}

		if ((ret = rtlx_init(*p)) < 0) {
		channel_wqs[index].in_open = 0;
		return ret;
		}
		if ((ret = rtlx_init(*p)) < 0)
		goto out_ret;
		}

		chan = &rtlx->channel[index];

		if (chan->lx_state == RTLX_STATE_OPENED) {
		channel_wqs[index].in_open = 0;
		return -EBUSY;
		state = xchg(&chan->lx_state, RTLX_STATE_OPENED);
		if (state == RTLX_STATE_OPENED) {
		ret = -EBUSY;
		goto out_fail;
		}

		chan->lx_state = RTLX_STATE_OPENED;
		channel_wqs[index].in_open = 0;
		return 0;

		out_fail:
		channel_wqs[index].in_open--;
		smp_mb();
		atomic_dec(&channel_wqs[index].in_open);
		smp_mb();

		out_ret:
		return ret;
		}

		@@ -475,7 +471,7 @@ static int rtlx_module_init(void)
		for (i = 0; i < RTLX_CHANNELS; i++) {
		init_waitqueue_head(&channel_wqs[i].rt_queue);
		init_waitqueue_head(&channel_wqs[i].lx_queue);
		channel_wqs[i].in_open = 0;
		atomic_set(&channel_wqs[i].in_open, 0);

		dev = device_create(mt_class, NULL, MKDEV(major, i),
		"%s%d", module_name, i);

arch/mips/kernel/vpe.c

+3 −4

Original line number	Diff line number	Diff line
		@@ -1079,6 +1079,7 @@ static int getcwd(char *buff, int size)
		static int vpe_open(struct inode inode, struct file filp)
		{
		int minor, ret;
		enum vpe_state state;
		struct vpe *v;
		struct vpe_notifications *not;

		@@ -1093,7 +1094,8 @@ static int vpe_open(struct inode inode, struct file filp)
		return -ENODEV;
		}

		if (v->state != VPE_STATE_UNUSED) {
		state = xchg(&v->state, VPE_STATE_INUSE);
		if (state != VPE_STATE_UNUSED) {
		dvpe();

		printk(KERN_DEBUG "VPE loader: tc in use dumping regs\n");
		@@ -1108,9 +1110,6 @@ static int vpe_open(struct inode inode, struct file filp)
		cleanup_tc(get_tc(minor));
		}

		// allocate it so when we get write ops we know it's expected.
		v->state = VPE_STATE_INUSE;

		/* this of-course trashes what was there before... */
		v->pbuffer = vmalloc(P_SIZE);
		v->plen = P_SIZE;