nfc: Fix hangup of RC-S380* in port100_send_ack()

If port100_send_ack() was called twice or more, it has race to hangup.

  port100_send_ack()          port100_send_ack()
    init_completion()
    [...]
    dev->cmd_cancel = true
                                /* this removes previous from completion */
                                init_completion()
				[...]
                                dev->cmd_cancel = true
                                wait_for_completion()
    /* never be waked up */
    wait_for_completion()

Like above race, this code is not assuming port100_send_ack() is
called twice or more.

To fix, this checks dev->cmd_cancel to know if prior cancel is
in-flight or not. And never be remove prior task from completion by
using reinit_completion(), so this guarantees to be waked up properly
soon or later.

Signed-off-by: OGAWA Hirofumi <[email protected]>
Signed-off-by: Samuel Ortiz <[email protected]>

0 files changed, 0 insertions, 0 deletions