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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: Dongxiao Xu <dongxiao.xu@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Dongxiao Xu 2009-05-31 14:43:42 +08:00 committed by Greg Kroah-Hartman
parent 171df63819
commit 72abd22883
2 changed files with 16 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
drivers/staging/heci/heci_main.c
View File

@ -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);

17
drivers/staging/heci/io_heci.c
View File

@ -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: