Merge "mhi: uci: Add channel mutex lock for read and write file ops" (723156f0) · Commits · e / devices / android_kernel_fairphone_FP5

drivers/bus/mhi/devices/mhi_uci.c

+28 −8

Original line number	Diff line number	Diff line
		@@ -27,6 +27,7 @@ struct uci_chan {
		struct list_head pending; /* user space waiting to read */
		struct uci_buf cur_buf; / current buffer user space reading */
		size_t rx_size;
		struct mutex chan_lock;
		};

		struct uci_buf {
		@@ -205,6 +206,8 @@ static int mhi_uci_release(struct inode inode, struct file file)
		MSG_LOG("Node is deleted, freeing dev node\n");
		mutex_unlock(&uci_dev->mutex);
		mutex_destroy(&uci_dev->mutex);
		mutex_destroy(&uci_dev->dl_chan.chan_lock);
		mutex_destroy(&uci_dev->ul_chan.chan_lock);
		clear_bit(MINOR(uci_dev->devt), uci_minors);
		kfree(uci_dev);
		return 0;
		@@ -274,11 +277,14 @@ static ssize_t mhi_uci_write(struct file *file,
		if (!buf \|\| !count)
		return -EINVAL;

		mutex_lock(&uci_chan->chan_lock);

		/* confirm channel is active */
		spin_lock_bh(&uci_chan->lock);
		if (!uci_dev->enabled) {
		spin_unlock_bh(&uci_chan->lock);
		return -ERESTARTSYS;
		ret = -ERESTARTSYS;
		goto err_mtx_unlock;
		}

		MSG_VERB("Enter: to xfer:%lu bytes\n", count);
		@@ -298,20 +304,22 @@ static ssize_t mhi_uci_write(struct file *file,

		if (ret == -ERESTARTSYS \|\| !uci_dev->enabled) {
		MSG_LOG("Exit signal caught for node or not enabled\n");
		return -ERESTARTSYS;
		ret = -ERESTARTSYS;
		goto err_mtx_unlock;
		}

		xfer_size = min_t(size_t, count, uci_dev->mtu);
		kbuf = kmalloc(xfer_size, GFP_KERNEL);
		if (!kbuf) {
		MSG_ERR("Failed to allocate memory %lu\n", xfer_size);
		return -ENOMEM;
		ret = -ENOMEM;
		goto err_mtx_unlock;
		}

		ret = copy_from_user(kbuf, buf, xfer_size);
		if (unlikely(ret)) {
		kfree(kbuf);
		return ret;
		goto err_mtx_unlock;
		}

		spin_lock_bh(&uci_chan->lock);
		@@ -339,12 +347,15 @@ static ssize_t mhi_uci_write(struct file *file,
		}

		spin_unlock_bh(&uci_chan->lock);
		mutex_unlock(&uci_chan->chan_lock);
		MSG_VERB("Exit: Number of bytes xferred:%lu\n", bytes_xfered);

		return bytes_xfered;

		sys_interrupt:
		spin_unlock_bh(&uci_chan->lock);
		err_mtx_unlock:
		mutex_unlock(&uci_chan->chan_lock);

		return ret;
		}
		@@ -367,11 +378,14 @@ static ssize_t mhi_uci_read(struct file *file,

		MSG_VERB("Client provided buf len:%lu\n", count);

		mutex_lock(&uci_chan->chan_lock);

		/* confirm channel is active */
		spin_lock_bh(&uci_chan->lock);
		if (!uci_dev->enabled) {
		spin_unlock_bh(&uci_chan->lock);
		return -ERESTARTSYS;
		ret = -ERESTARTSYS;
		goto err_mtx_unlock;
		}

		/* No data available to read, wait */
		@@ -384,7 +398,8 @@ static ssize_t mhi_uci_read(struct file *file,
		!list_empty(&uci_chan->pending)));
		if (ret == -ERESTARTSYS) {
		MSG_LOG("Exit signal caught for node\n");
		return -ERESTARTSYS;
		ret = -ERESTARTSYS;
		goto err_mtx_unlock;
		}

		spin_lock_bh(&uci_chan->lock);
		@@ -418,7 +433,7 @@ static ssize_t mhi_uci_read(struct file *file,
		ptr = uci_buf->data + (uci_buf->len - uci_chan->rx_size);
		ret = copy_to_user(buf, ptr, to_copy);
		if (ret)
		return ret;
		goto err_mtx_unlock;

		MSG_VERB("Copied %lu of %lu bytes\n", to_copy, uci_chan->rx_size);
		uci_chan->rx_size -= to_copy;
		@@ -445,12 +460,14 @@ static ssize_t mhi_uci_read(struct file *file,
		}

		MSG_VERB("Returning %lu bytes\n", to_copy);
		mutex_unlock(&uci_chan->chan_lock);

		return to_copy;

		read_error:
		spin_unlock_bh(&uci_chan->lock);

		err_mtx_unlock:
		mutex_unlock(&uci_chan->chan_lock);
		return ret;
		}

		@@ -557,6 +574,8 @@ static void mhi_uci_remove(struct mhi_device *mhi_dev)
		if (!uci_dev->ref_count) {
		mutex_unlock(&uci_dev->mutex);
		mutex_destroy(&uci_dev->mutex);
		mutex_destroy(&uci_dev->dl_chan.chan_lock);
		mutex_destroy(&uci_dev->ul_chan.chan_lock);
		clear_bit(MINOR(uci_dev->devt), uci_minors);
		kfree(uci_dev);
		mutex_unlock(&mhi_uci_drv.lock);
		@@ -615,6 +634,7 @@ static int mhi_uci_probe(struct mhi_device *mhi_dev,
		struct uci_chan *uci_chan = (dir) ?
		&uci_dev->ul_chan : &uci_dev->dl_chan;
		spin_lock_init(&uci_chan->lock);
		mutex_init(&uci_chan->chan_lock);
		init_waitqueue_head(&uci_chan->wq);
		INIT_LIST_HEAD(&uci_chan->pending);
		}