NFC: digital: Clear poll_tech_count before activating target
Currently, digital_target_found() has a race between the events started by calling nfc_targets_found() (which ultimately expect ddev->poll_tech_count to be zero) and setting ddev->poll_tech_count to zero after the call to nfc_targets_found(). When the race is "lost" (i.e., ddev->poll_tech_count is found to not be zero by the events started by nfc_targets_found()), an error message is printed and the target is not found. A similar race exists when digital_tg_recv_atr_req() calls nfc_tm_activated(). Fix this by first saving the current value of ddev->poll_tech_count and then clearing it before calling nfc_targets_found()/nfc_tm_activated(). Clearing ddev->poll_tech_count before calling nfc_targets_found()/nfc_tm_activated() eliminates the race. Saving the value is required so it can be restored when nfc_targets_found()/nfc_tm_activated() fails and polling needs to continue. Acked-by: Thierry Escande <thierry.escande@linux.intel.com> Signed-off-by: Mark A. Greer <mgreer@animalcreek.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
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