On 6/25/24 3:04 AM, Peter Wang (王信友) wrote:
When eh_timed_out() called concurrently with the regular completion handler. Both process use test_and_set_bit(SCMD_STATE_COMPLETE, &cmd->state) to set SCMD_STATE_COMPLETE flag. test_and_set_bit should be atomice operation? and only one can set this bit than run forward?
Yes, only one of the two test_and_set_bit(SCMD_STATE_COMPLETE, &cmd->state) calls will set the SCMD_STATE_COMPLETE bit and only one of these two calls will return the value 'true'.
BTW, I still don't understand if both eh_timed_out and regular completion handler set SCMD_STATE_COMPLETE, what is the relation between SCMD_STATE_COMPLETE and ufshcd_queuecommand null pointer?
While ufshcd_eh_timed_out() does not set the SCMD_STATE_COMPLETE bit, its caller may set that bit after ufshcd_eh_timed_out() has returned. Hence, a command may be completed while ufshcd_eh_timed_out() is in progress. Thanks, Bart.
