Commit 986d555a authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'rpmsg-v7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/remoteproc/linux 

Pull rpmsg updates from Bjorn Andersson:

 - Fix a race in rpmsg driver_override_show() and use the existing
   helper to implement the store()

 - Implement support for EPOLLOUT in the virtio rpmsg driver

* tag 'rpmsg-v7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/remoteproc/linux:
  rpmsg: core: fix race in driver_override_show() and use core helper
  rpmsg: virtio: EPOLLOUT support
parents 2bfc50c6 42023d4b

drivers/rpmsg/rpmsg_core.c

+27 −39
Original line number Diff line number Diff line
@@ -352,50 +352,38 @@ field##_show(struct device *dev, \ 
}									\

static DEVICE_ATTR_RO(field);



#define rpmsg_string_attr(field, member)				\

static ssize_t								\

field##_store(struct device *dev, struct device_attribute *attr,	\

	      const char *buf, size_t sz)				\

{									\

	struct rpmsg_device *rpdev = to_rpmsg_device(dev);		\

	const char *old;						\

	char *new;							\

									\

	new = kstrndup(buf, sz, GFP_KERNEL);				\

	if (!new)							\

		return -ENOMEM;						\

	new[strcspn(new, "\n")] = '\0';					\

									\

	device_lock(dev);						\

	old = rpdev->member;						\

	if (strlen(new)) {						\

		rpdev->member = new;					\

	} else {							\

		kfree(new);						\

		rpdev->member = NULL;					\

	}								\

	device_unlock(dev);						\

									\

	kfree(old);							\

									\

	return sz;							\

}									\

static ssize_t								\

field##_show(struct device *dev,					\

	     struct device_attribute *attr, char *buf)			\

{									\

	struct rpmsg_device *rpdev = to_rpmsg_device(dev);		\

									\

	return sprintf(buf, "%s\n", rpdev->member);			\

}									\

static DEVICE_ATTR_RW(field)



/* for more info, see Documentation/ABI/testing/sysfs-bus-rpmsg */

rpmsg_show_attr(name, id.name, "%s\n");

rpmsg_show_attr(src, src, "0x%x\n");

rpmsg_show_attr(dst, dst, "0x%x\n");

rpmsg_show_attr(announce, announce ? "true" : "false", "%s\n");

rpmsg_string_attr(driver_override, driver_override);



static ssize_t driver_override_store(struct device *dev,

				     struct device_attribute *attr,

				     const char *buf, size_t count)

{

	struct rpmsg_device *rpdev = to_rpmsg_device(dev);

	int ret;



	ret = driver_set_override(dev, &rpdev->driver_override, buf, count);

	if (ret)

		return ret;



	return count;

}



static ssize_t driver_override_show(struct device *dev,

				    struct device_attribute *attr, char *buf)

{

	struct rpmsg_device *rpdev = to_rpmsg_device(dev);

	ssize_t len;



	device_lock(dev);

	len = sysfs_emit(buf, "%s\n", rpdev->driver_override);

	device_unlock(dev);

	return len;

}

static DEVICE_ATTR_RW(driver_override);



static ssize_t modalias_show(struct device *dev,

			     struct device_attribute *attr, char *buf)

drivers/rpmsg/virtio_rpmsg_bus.c

+32 −69
Original line number Diff line number Diff line
@@ -41,13 +41,12 @@ 
 * @buf_size:   size of one rx or tx buffer

 * @last_sbuf:	index of last tx buffer used

 * @bufs_dma:	dma base addr of the buffers

 * @tx_lock:	protects svq, sbufs and sleepers, to allow concurrent senders.

 * @tx_lock:	protects svq and sbufs, to allow concurrent senders.

 *		sending a message might require waking up a dozing remote

 *		processor, which involves sleeping, hence the mutex.

 * @endpoints:	idr of local endpoints, allows fast retrieval

 * @endpoints_lock: lock of the endpoints set

 * @sendq:	wait queue of sending contexts waiting for a tx buffers

 * @sleepers:	number of senders that are waiting for a tx buffer

 *

 * This structure stores the rpmsg state of a given virtio remote processor

 * device (there might be several virtio proc devices for each physical
@@ -65,7 +64,6 @@ struct virtproc_info { 
	struct idr endpoints;

	struct mutex endpoints_lock;

	wait_queue_head_t sendq;

	atomic_t sleepers;

};



/* The feature bitmap for virtio rpmsg */
@@ -144,6 +142,8 @@ static int virtio_rpmsg_sendto(struct rpmsg_endpoint *ept, void *data, int len, 
static int virtio_rpmsg_trysend(struct rpmsg_endpoint *ept, void *data, int len);

static int virtio_rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data,

				  int len, u32 dst);

static __poll_t virtio_rpmsg_poll(struct rpmsg_endpoint *ept, struct file *filp,

				  poll_table *wait);

static ssize_t virtio_rpmsg_get_mtu(struct rpmsg_endpoint *ept);

static struct rpmsg_device *__rpmsg_create_channel(struct virtproc_info *vrp,

						   struct rpmsg_channel_info *chinfo);
@@ -154,6 +154,7 @@ static const struct rpmsg_endpoint_ops virtio_endpoint_ops = { 
	.sendto = virtio_rpmsg_sendto,

	.trysend = virtio_rpmsg_trysend,

	.trysendto = virtio_rpmsg_trysendto,

	.poll = virtio_rpmsg_poll,

	.get_mtu = virtio_rpmsg_get_mtu,

};
@@ -436,7 +437,6 @@ static void *get_a_tx_buf(struct virtproc_info *vrp) 
	unsigned int len;

	void *ret;



	/* support multiple concurrent senders */

	mutex_lock(&vrp->tx_lock);



	/*
@@ -454,62 +454,6 @@ static void *get_a_tx_buf(struct virtproc_info *vrp) 
	return ret;

}



/**

 * rpmsg_upref_sleepers() - enable "tx-complete" interrupts, if needed

 * @vrp: virtual remote processor state

 *

 * This function is called before a sender is blocked, waiting for

 * a tx buffer to become available.

 *

 * If we already have blocking senders, this function merely increases

 * the "sleepers" reference count, and exits.

 *

 * Otherwise, if this is the first sender to block, we also enable

 * virtio's tx callbacks, so we'd be immediately notified when a tx

 * buffer is consumed (we rely on virtio's tx callback in order

 * to wake up sleeping senders as soon as a tx buffer is used by the

 * remote processor).

 */

static void rpmsg_upref_sleepers(struct virtproc_info *vrp)

{

	/* support multiple concurrent senders */

	mutex_lock(&vrp->tx_lock);



	/* are we the first sleeping context waiting for tx buffers ? */

	if (atomic_inc_return(&vrp->sleepers) == 1)

		/* enable "tx-complete" interrupts before dozing off */

		virtqueue_enable_cb(vrp->svq);



	mutex_unlock(&vrp->tx_lock);

}



/**

 * rpmsg_downref_sleepers() - disable "tx-complete" interrupts, if needed

 * @vrp: virtual remote processor state

 *

 * This function is called after a sender, that waited for a tx buffer

 * to become available, is unblocked.

 *

 * If we still have blocking senders, this function merely decreases

 * the "sleepers" reference count, and exits.

 *

 * Otherwise, if there are no more blocking senders, we also disable

 * virtio's tx callbacks, to avoid the overhead incurred with handling

 * those (now redundant) interrupts.

 */

static void rpmsg_downref_sleepers(struct virtproc_info *vrp)

{

	/* support multiple concurrent senders */

	mutex_lock(&vrp->tx_lock);



	/* are we the last sleeping context waiting for tx buffers ? */

	if (atomic_dec_and_test(&vrp->sleepers))

		/* disable "tx-complete" interrupts */

		virtqueue_disable_cb(vrp->svq);



	mutex_unlock(&vrp->tx_lock);

}



/**

 * rpmsg_send_offchannel_raw() - send a message across to the remote processor

 * @rpdev: the rpmsg channel
@@ -582,9 +526,6 @@ static int rpmsg_send_offchannel_raw(struct rpmsg_device *rpdev, 


	/* no free buffer ? wait for one (but bail after 15 seconds) */

	while (!msg) {

		/* enable "tx-complete" interrupts, if not already enabled */

		rpmsg_upref_sleepers(vrp);



		/*

		 * sleep until a free buffer is available or 15 secs elapse.

		 * the timeout period is not configurable because there's
@@ -595,9 +536,6 @@ static int rpmsg_send_offchannel_raw(struct rpmsg_device *rpdev, 
					(msg = get_a_tx_buf(vrp)),

					msecs_to_jiffies(15000));



		/* disable "tx-complete" interrupts if we're the last sleeper */

		rpmsg_downref_sleepers(vrp);



		/* timeout ? */

		if (!err) {

			dev_err(dev, "timeout waiting for a tx buffer\n");
@@ -676,6 +614,34 @@ static int virtio_rpmsg_trysendto(struct rpmsg_endpoint *ept, void *data, 
	return rpmsg_send_offchannel_raw(rpdev, src, dst, data, len, false);

}



static __poll_t virtio_rpmsg_poll(struct rpmsg_endpoint *ept, struct file *filp,

				  poll_table *wait)

{

	struct rpmsg_device *rpdev = ept->rpdev;

	struct virtio_rpmsg_channel *vch = to_virtio_rpmsg_channel(rpdev);

	struct virtproc_info *vrp = vch->vrp;

	__poll_t mask = 0;



	poll_wait(filp, &vrp->sendq, wait);



	/* support multiple concurrent senders */

	mutex_lock(&vrp->tx_lock);



	/*

	 * check for a free buffer, either:

	 * - we haven't used all of the available transmit buffers (half of the

	 *   allocated buffers are used for transmit, hence num_bufs / 2), or,

	 * - we ask the virtqueue if there's a buffer available

	 */

	if (vrp->last_sbuf < vrp->num_bufs / 2 ||

	    !virtqueue_enable_cb(vrp->svq))

		mask |= EPOLLOUT;



	mutex_unlock(&vrp->tx_lock);



	return mask;

}



static ssize_t virtio_rpmsg_get_mtu(struct rpmsg_endpoint *ept)

{

	struct rpmsg_device *rpdev = ept->rpdev;
@@ -922,9 +888,6 @@ static int rpmsg_probe(struct virtio_device *vdev) 
		WARN_ON(err); /* sanity check; this can't really happen */

	}



	/* suppress "tx-complete" interrupts */

	virtqueue_disable_cb(vrp->svq);



	vdev->priv = vrp;



	rpdev_ctrl = rpmsg_virtio_add_ctrl_dev(vdev);