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Commit 72abd228 authored by Dongxiao Xu's avatar Dongxiao Xu Committed by Greg Kroah-Hartman
Browse files

Staging: heci: fix spinlock order mess of device_lock and read_io_lock 



In orginal code, the device_lock and read_io_lock is mess order when nested,
which may bring dead lock. This patch unify the spinlock order of device_lock
and read_io_lock. First acquire device_lock, then read_io_lock.

Signed-off-by: default avatarDongxiao Xu <dongxiao.xu@intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 171df638

drivers/staging/heci/heci_main.c

+1 −1
Original line number Diff line number Diff line
@@ -954,8 +954,8 @@ static ssize_t heci_read(struct file *file, char __user *ubuf, 
		goto out;

	}



	spin_lock(&file_ext->read_io_lock);

	err = heci_start_read(dev, if_num, file_ext);

	spin_lock(&file_ext->read_io_lock);

	if (err != 0 && err != -EBUSY) {

		DBG("heci start read failure with status = %d\n", err);

		spin_unlock(&file_ext->read_io_lock);

drivers/staging/heci/io_heci.c

+15 −2
Original line number Diff line number Diff line
@@ -637,8 +637,9 @@ int heci_start_read(struct iamt_heci_device *dev, int if_num, 
		DBG("received wrong function input param.\n");

		return -ENODEV;

	}

	if (file_ext->state != HECI_FILE_CONNECTED)

	if (file_ext->state != HECI_FILE_CONNECTED) {

		return -ENODEV;

	}



	spin_lock_bh(&dev->device_lock);

	if (dev->heci_state != HECI_ENABLED) {
@@ -647,18 +648,26 @@ int heci_start_read(struct iamt_heci_device *dev, int if_num, 
	}

	spin_unlock_bh(&dev->device_lock);

	DBG("check if read is pending.\n");

	spin_lock(&file_ext->read_io_lock);

	if ((file_ext->read_pending) || (file_ext->read_cb != NULL)) {

		DBG("read is pending.\n");

		spin_unlock(&file_ext->read_io_lock);

		return -EBUSY;

	}

	spin_unlock(&file_ext->read_io_lock);



	priv_cb = kzalloc(sizeof(struct heci_cb_private), GFP_KERNEL);

	if (!priv_cb)

		return -ENOMEM;



	spin_lock(&file_ext->read_io_lock);

	DBG("allocation call back success\n"

	    "host client = %d, ME client = %d\n",

	    file_ext->host_client_id, file_ext->me_client_id);

	spin_unlock(&file_ext->read_io_lock);



	spin_lock_bh(&dev->device_lock);

	spin_lock(&file_ext->read_io_lock);

	for (i = 0; i < dev->num_heci_me_clients; i++) {

		if (dev->me_clients[i].client_id == file_ext->me_client_id)

			break;
@@ -666,6 +675,7 @@ int heci_start_read(struct iamt_heci_device *dev, int if_num, 
	}



	BUG_ON(dev->me_clients[i].client_id != file_ext->me_client_id);

	spin_unlock(&file_ext->read_io_lock);

	if (i == dev->num_heci_me_clients) {

		rets = -ENODEV;

		goto unlock;
@@ -684,12 +694,14 @@ int heci_start_read(struct iamt_heci_device *dev, int if_num, 
	/* make sure information is zero before we start */

	priv_cb->information = 0;

	priv_cb->file_private = (void *) file_ext;

	file_ext->read_cb = priv_cb;

	spin_lock_bh(&dev->device_lock);

	spin_lock(&file_ext->read_io_lock);

	file_ext->read_cb = priv_cb;

	if (dev->host_buffer_is_empty) {

		dev->host_buffer_is_empty = 0;

		if (!heci_send_flow_control(dev, file_ext)) {

			rets = -ENODEV;

			spin_unlock(&file_ext->read_io_lock);

			goto unlock;

		} else {

			list_add_tail(&priv_cb->cb_list,
@@ -699,6 +711,7 @@ int heci_start_read(struct iamt_heci_device *dev, int if_num, 
		list_add_tail(&priv_cb->cb_list,

			      &dev->ctrl_wr_list.heci_cb.cb_list);

	}

	spin_unlock(&file_ext->read_io_lock);

	spin_unlock_bh(&dev->device_lock);

	return rets;

unlock: