Stall error handler if attempting resets/aborts while an rport is blocked.
This avoids device offline scenarios due to errors in the error handler.
Background:
Although the transport is using the scsi_timed_out functionality to
restart the timeout if the rport is blocked, if the timeout has already
fired before the block occurs, the eh handler still runs and can take
the device offline. Ultimately, this window cannot be resolved without
significant work in the error handler thread. Christoph noted the first
level of these issues when he noted the poor error response handling
by the error thread.
We found, under heavy load and error testing, that time window from when
the scsi_times_out() adds the io to the queue to when the scsi_error_handler
gets around to servicing it, can be in the several seconds range. In most
cases, these test conditions are highly unusual, but possible.
As a result, we're stalling the error handler in this race window so that
we can avoid the device_offline transitions.
Signed-off-by: James Smart <James.Smart@emulex.com>
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
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