From: Chuansheng Liu <chuansheng.liu@intel.com>
Date: Thu, 8 Nov 2012 11:14:40 +0000 (+0800)
Subject: firmware loader: Fix the race FW_STATUS_DONE is followed by class_timeout
X-Git-Tag: omap-for-v3.8/fixes-for-merge-window-v4-signed~86^2~88
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=ce2fcbd99cef580623116bb33531dbc3e6f690b0;p=pandora-kernel.git

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>
---

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