This patch fixes the race condition when one thread tries to destroy
the memory allocated for rx_roq, while another thread still happen
to access rx_roq.
Such a race condition occurs when i2400m-sdio kernel module gets
unloaded, destroying the memory allocated for rx_roq while rx_roq
is accessed by i2400m_rx_edata(), as explained below:
$thread1 $thread2
$ void i2400m_rx_edata() $
$Access rx_roq[] $
$roq = &i2400m->rx_roq[ro_cin] $
$ i2400m_roq_[reset/queue/update_ws] $
$ $ void i2400m_rx_release();
$ $kfree(rx->roq);
$ $rx->roq = NULL;
$Oops! rx_roq is NULL
This patch fixes the race condition using refcount approach.
Signed-off-by: Prasanna S. Panchamukhi <prasannax.s.panchamukhi@intel.com>
d11a6e4495