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firmware loader: Fix the race FW_STATUS_DONE is followed by class_timeout 

There is a race as below when calling request_firmware():
CPU1                                   CPU2
write 0 > loading
mutex_lock(&fw_lock)
...
set_bit FW_STATUS_DONE                 class_timeout is coming
                                       set_bit FW_STATUS_ABORT
complete_all &completion
...
mutex_unlock(&fw_lock)

In this time, the bit FW_STATUS_DONE and FW_STATUS_ABORT are set,
and request_firmware() will return failure due to condition in
_request_firmware_load():
	if (!buf->size || test_bit(FW_STATUS_ABORT, &buf->status))
		retval = -ENOENT;

But from the above scenerio, it should be a successful requesting.
So we need judge if the bit FW_STATUS_DONE is already set before
calling fw_load_abort() in timeout function.

As Ming's proposal, we need change the timer into sched_work to
benefit from using &fw_lock mutex also.

Signed-off-by: liu chuansheng <chuansheng.liu@intel.com>
Acked-by: Ming Lei <ming.lei@canonical.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Chuansheng Liu 2012-11-08 19:14:40 +08:00 committed by Greg Kroah-Hartman
parent ecdca043eb
commit ce2fcbd99c
1 changed files with 16 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

24
drivers/base/firmware_class.c
View File

@ -143,7 +143,7 @@ struct fw_cache_entry {
};
struct firmware_priv {
struct timer_list timeout;
struct delayed_work timeout_work;
bool nowait;
struct device dev;
struct firmware_buf *buf;
@ -667,11 +667,18 @@ static struct bin_attribute firmware_attr_data = {
.write = firmware_data_write,
};
static void firmware_class_timeout(u_long data)
static void firmware_class_timeout_work(struct work_struct *work)
{
struct firmware_priv *fw_priv = (struct firmware_priv *) data;
struct firmware_priv *fw_priv = container_of(work,
struct firmware_priv, timeout_work.work);
mutex_lock(&fw_lock);
if (test_bit(FW_STATUS_DONE, &(fw_priv->buf->status))) {
mutex_unlock(&fw_lock);
return;
}
fw_load_abort(fw_priv);
mutex_unlock(&fw_lock);
}
static struct firmware_priv *
@ -690,8 +697,8 @@ fw_create_instance(struct firmware *firmware, const char *fw_name,
fw_priv->nowait = nowait;
fw_priv->fw = firmware;
setup_timer(&fw_priv->timeout,
firmware_class_timeout, (u_long) fw_priv);
INIT_DELAYED_WORK(&fw_priv->timeout_work,
firmware_class_timeout_work);
f_dev = &fw_priv->dev;
@ -858,7 +865,9 @@ static int _request_firmware_load(struct firmware_priv *fw_priv, bool uevent,
dev_dbg(f_dev->parent, "firmware: direct-loading"
" firmware %s\n", buf->fw_id);
mutex_lock(&fw_lock);
set_bit(FW_STATUS_DONE, &buf->status);
mutex_unlock(&fw_lock);
complete_all(&buf->completion);
direct_load = 1;
goto handle_fw;
@ -894,15 +903,14 @@ static int _request_firmware_load(struct firmware_priv *fw_priv, bool uevent,
dev_set_uevent_suppress(f_dev, false);
dev_dbg(f_dev, "firmware: requesting %s\n", buf->fw_id);
if (timeout != MAX_SCHEDULE_TIMEOUT)
mod_timer(&fw_priv->timeout,
round_jiffies_up(jiffies + timeout));
schedule_delayed_work(&fw_priv->timeout_work, timeout);
kobject_uevent(&fw_priv->dev.kobj, KOBJ_ADD);
}
wait_for_completion(&buf->completion);
del_timer_sync(&fw_priv->timeout);
cancel_delayed_work_sync(&fw_priv->timeout_work);
handle_fw:
mutex_lock(&fw_lock);